Gorilla Glue #4 Grow Journal and Week-by-Week Guide

This is a complete guide to growing Gorilla Glue week by week indoors. In it, we go into details of this strain’s cultivation from seed to harvest, using one real-life Gorilla Glue #4 grow journal as an example and occasionally drawing on data from other grow reports.

Canadian (Master, 159 likes, 27 diaries)

“This girl has been a complete pleasure to grow he is very easy very resiting to nutrients and a very hight-quality flower”

We describe a grow cycle that took 14 weeks from seed (10 weeks of flowering) and yielded 159 grams (5.62 ounces) of premium bud. Along the way, we discuss what’s needed to successfully grow Gorilla Glue #4 indoors, how to maintain perfect conditions, and what nutrients and cultivation methods to use.

You’ll see for yourself that Gorilla Glue 4 isn’t hard to grow. She’s resilient to stress and responds well to topping, LST, and super cropping but may stretch too much in flower and needs smart canopy management. And she doesn’t require fancy nutrient schedules to deliver above-average yields.

Gorilla Glue #4 (Original Sensible Seeds)

The GG#4 cannabis seeds are continuously astonishing us with their impressive results! It’s remarkable that indoor growers can yield up to 800g/m2 (2.2oz/ft2) with this strain, and outdoor cultivators can obtain up to a kilogram (2.2lb) per plant. The Gorilla Glue #4 only requires 56 to 63 days to complete flowering after switching to a 12/12 light cycle.

Setup Highlights

For our review, we’ve chosen a Gorilla Glue #4 grow journal by Canadian. The guy uses a 3’x3’ tent equipped with a 400W HPS. It’s a pretty much standard setup, an old tried warhorse of millions of weed growers worldwide.

Even if you don’t smoke much, we recommend starting with a similar-size grow tent because in smaller spaces, it’s more difficult to control temperature and you can’t fit it with a powerful light. And weaker lights produce insubstantial yields of smaller and airier buds. Bigger tents are also more convenient in terms of watering and canopy management.

Surface Area Light
9.8 ft2 (0.91 m2) 400W
No. of Plants Overall Yield
3 15.63 oz (443 g)
Yield per Plant Yield per Watt
5.22 oz (148 g) 1.1 g

Gorilla Glue Veg Time

We’ll start our Gorilla Glue #4 grow journal by describing the plant’s progress through the vegetative phase.

Gorilla Glue #4 is a classic photoperiod variety which means that it’s up to you to decide on its veg time. This particular grower was vegging his plant for 4 weeks and then switched his timer to 12/12 to induce flowering.

In grow reports available online, people veg GG4 for anywhere from 3 to 8 weeks. And even 15 weeks in one case.

As with any other strain, the duration of the veg for GG4 depends on a lot of factors, for example, the number of transplants or the volume of the final pot. But the most important factor is the height of the plant at harvest which is limited by your available vertical space. Please note that Gorilla Glue #4 is a rather leggy plant and stretches A LOT in flower. In this instance, she went from 16 to 68 inches (41 to 173 cm), more than quadrupling in size.

But let’s not get ahead of ourselves and start with germination.

Week 1: What Are the Best Conditions for a GG4 Seedling?

A 3-day-old Gorilla Glue seedling growing in a coco/perlite mix

Three days out of the soil, and our Gorilla Glue grow report begins. © Growdiaries © Canadian

There are a lot of ways to germinate cannabis seeds, and even the crudest, intentionally low-tech methods give you good results if you follow three simple rules: moisture, warmth, and darkness.

You may simply germinate your Gorilla Glue bean by placing it into moistened soil about half an inch (1 cm) deep. It will usually take about 3 days to see the sprout. Aim for 23-26 °C (73-79 °F) for best results.

We understand that it’s too much anxiety for a newbie gardener to wait that long without any feedback. That’s why most people prefer to first germinate a bean between wet paper towels and monitor it as often as they want. Good viable seeds can show the taproot in just 12 hours, and then you can put the sprout in the soil.

After your Gorilla seedling has popped above the surface try to make sure that she sheds the helmet head as soon as possible. Otherwise, it will delay growth. Make the outer shell wet and soft, and you will remove it easily with your fingers.

Keep the environment warm and humid, and use a humidity dome if necessary. The perfect relative humidity for cannabis is the same as recommended for people to be comfortable indoors—between 40 and 60 percent. You can go higher than that for the seedling stage (up to 80%), but the more mature your plant gets, the lower the RH should be.

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And when the flowering stages begin for your Gorilla Glue, it’s all the more important to keep the air on the dry side. Beginner growers may find it hard to believe, but marijuana buds can get as moldy as a strawberry or a plum that you left in the fridge for too long. Only with buds, it can happen practically overnight.

In the chart below, you can compare the actual RH in our Gorilla Glue #4 grow journal and the optimal levels that you should aim for:

Gorilla Glue #4 Grow Journal and Week-by-Week Guide: Realative humidity chart

Actual and recommended RH levels for Gorilla Glue week by week.

In the first week from seed, your Gorilla Glue won’t drink much. So spray the surface or water something like half a cup around the base of the stem every couple of days. Of course, if you have pre-moistened the whole volume of your medium in advance.

If you grow your GG4 in soil, she will now find enough nutrients to flourish. In the grow report that we review here, the gardener used a coco/perlite mix (Fox Farm Ko Ko Bop) with a classical ratio of 70/30 percent.

Coco coir is best at retaining water, while perlite creates air pockets in the medium so that roots have oxygen to breathe. Together they make the winning combo. For the same reason, perlite is also beneficial in soil grows.

Some ready-made coco mixes (like this one) are amended with calcium and magnesium and pre-loaded with other essential nutrients. Others are sterile and so require using nutrients (very small doses at first) from practically day one. Starting from the second week, most growers—no matter what medium they use—start giving their cannabis extra nutrients when watering.

A very important consideration in the seedling stage is the distance from the light. Make sure it’s far enough that the little baby is reaching toward the light but doesn’t get too stretchy to topple over.

Let’s have a look at how the light distance was changing for this Gorilla Glue week by week. (Note that she was growing under a 400W HPS; for other lights, you’ll have to find the optimal distance experimentally.)

Gorilla Glue #4 Grow Journal and Week-by-Week Guide: Light distance chart

Light distance for the whole of Gorilla Glue 4 grow report.

Week 2: GG4 Grows Huge Fan Leaves

A young Gorilla Glue 4 plant at the age of 9 and 15 days growing in a smart pot filled with coco medium

A vigorous progress in week 2 © Growdiaries © Canadian

In the second week from seed, most of the development is still happening underground as roots spread through the medium in search of water and nutrients. The leaves are growing only imperceptibly. Look at their size on day 10: if the first and the second pair span about the same, you’re on schedule.

The more the surface area of fan leaves, the faster they grow. Until something clicks and they explode, which for this Gorilla Glue #4 happened at the beginning of the third week.

The grower noted how quickly his 7 liters of Fox Farm Ko Ko Bop medium was drying. On the one hand, it means more work for you because you’ll have to water more often. On the other, frequently going through wet/dry cycles gives roots the opportunity to both drink and breathe all the time. Cannabis just loves that and grows like crazy. Install an automatic drip system, and you’ll get the maximum benefit from growing in coco.

Godzilla Glue (Herbies Seeds)

THC – 29%
Feminized
50% Sativa/50% Indica

Gorilla Glue Auto (FastBuds)

THC – 24%
Autoflowering
65% Sativa/35% Indica

However, in this Gorilla Glue 4 grow, all watering was done by hand and starting from week 2, the gardener began feeding his girl nutrients. You should keep in mind that weed plants need more nitrogen than phosphorus and potassium in veg. And if you grow in coco, be sure to add lots of calcium and magnesium throughout the life cycle.

It’s safer to start with lower doses of nutrients than their manufacturer recommends. This way you’ll avoid burning young and sensitive roots. Later, if all is well, you’ll get to the recommended values.

Week 3: Topping GG4 And Then Defoliating

A 21-day-old Gorilla Glue #4 trained and overgrowing her fabric pot

Gorilla Glue #4 at the end of week 3 (before and after defoliation) © Growdiaries © Canadian

In the third week from seed, Gorilla Glue 4 looked so well-developed that the grower began to high-stress train her without second thoughts. The purpose of training—both low- and high-stress—is to stimulate side growth, making a bushier and more low-profile plant. It’s of utmost importance indoors where you better keep all the tops at exactly the same distance from the light. This way, you get many buds of the same size and quality.

He started with FIMming. The legend says that this curious procedure was discovered by chance—when a grower “botched” his attempt at regular topping and exclaimed “Fuck, I missed!”, or FIM for short.

When topping cannabis in a usual way, you cut the tip clean, leaving intact two tiny shoots below the cut. These will grow into two full-fledged new apexes (tops) instead of just one.

With fimming, you make the cut either a bit higher or a bit lower, cutting through the side shoots as well. At first, they grow all fucked up and mangled but then recover and—together with the two shoots just below—form four (!) apexes instead of one. And while this process is underway, the lower side shoots also get a major boost.

In the pic below, we have shown in red where the cut for a regular topping could have been made.

GG4 on day 17, befotre and after topping, with cuts and future tops marked

The number of apexes (tops) goes from 1 to 4 when you FIM your cannabis © Growdiaries © Canadian

Several days after the topping, the guy also defoliated his GG4, and rather heavily. The purpose of defoliation is to expose those growing points that are shaded by fan leaves. It’s a perfectly reasonable consideration, but we think many growers get carried away playing Edward Scissorhands.

When plants are stripped down next to nothing, they may LOOK all gorgeous and curvy in flower, suggesting enormous production, but in our experience, extreme defoliation rarely leads to better yields. With that said, the jury’s still out.

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Week 4: Gorilla Glue #4 Veg Time is Coming to an End

A top view and a side view of a 3-week-old Gorilla Glue, heavily defoliated and tied down

GG4 is topped, defoliated, tied-down, and ready for 12/12 © Growdiaries © Canadian

The grower would switch to 12/12 (for flowering initiation) by the end of the first month from seed. Four weeks is not terribly long veg, but in this case, it was the right move to end it so early because even at this point the plant was stretchy.

The guy had to work now all the time, adjusting the ties and trying to keep his Gorilla Glue stretch from getting out of hand. (Btw, using an HPS with all those reds in the spectrum contributes to stretching.) He was also taking pains not to stress his girl too much by LST because he was afraid she could hermie on him.

He also made a change to the diet by adding GHE FloraNectar Fruit-n-Fusion. This supplement contains different carbohydrates from things like cane sugar and molasses, is rich in potassium, magnesium, and sulfur, and is a good way to prepare for the needs of the flowering stage.

Besides, all those sugars are a great source of energy for a plant that is being constantly defoliated. Remember that leaves produce energy in the form of sugars and starches. If you pluck them all the time, be sure to substitute the loss with something else.

And here is the feeding schedule for the whole of the vegetative phase and the first week of 12/12.

Nutrients, ml/gal Week 2 Week 3 Week 4 Week 5
CALiMAGic 4 4 5 5
FloraMicro 2.5 2.5 3 3
FloraGro 2 2 2.5 3
FloraBloom 1 1 2.5 3
FloraNectar Fruit-n-Fusion 3.79 3.79

The nutrient schedule for the veg part of GG4 grow diary.

Gorilla Glue Flowering Stages

To induce flowering in Gorilla Glue #4 (or any other photoperiod strain) you need to reprogram your timer to 12 hrs of light and 12 hrs of darkness (12/12). Some growers start counting flowering time from the day they flip the switch but bear in mind that the budding doesn’t start right away.

Depending on the genetics, it may take anywhere from one to two weeks before you even see the first signs of flowering—the so-called pistils, or female hairs. This process may be even slower if there’s only been short veg and the plant hasn’t had a chance to mature.

Gorilla Glue is a quite fast variety. The flowering stage is about 8–10 weeks long. At least, that’s how many weeks of 12/12 you’ll need. The first one or two weeks are a transition period, and then Gorilla Glue starts to bud for real.

Week 5: Gorilla Glue Stretch Continues

Gorilla Glue 4 at day 29, before and after another heavy defoliation

Gorilla Glue 4 before and after defoliation © Growdiaries © Canadian

At this point in the timeline, Gorilla Glue was the tallest among 4 different strains. Her height and legginess were the reason the gardener had ended the veg so early. He was simply afraid she would otherwise use up all available vertical space and also spread sideways.

He continued with heavy defoliation. When plucking the leaves, he noted their very dank smell. This is by the way how professional breeders choose the most promising phenotypes early on—by rubbing and smelling their leaves.

On day 30, the guy undid all the ties. From now on, the girl would continue to grow untrained. Besides being tall and stretchy, GG4 was also the thirstiest plant in the garden. She was still in her initial 7-liter (1.85-gal) smart pot.

Week 6: After Many Haircuts, GG4 is Still Very Bushy

A very dense-looking Gorilla Glue on days 35 and 43 from seed; no sign of flowers yet

After two weeks of 12/12, the flowering stretch is in, but there’s still no budding © Growdiaries © Canadian

The photos above give you an idea of how quickly a healthy weed plant bounces back after even extreme defoliation. And how quickly everything reverts back to the “jungle” state. Which raises the question of whether removing the fan leaves is worth it in the first place.

Maybe all you really need is to prune the excess branches: those that are too far down the stem and those that grow inside the canopy.

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It’s very easy to spot the branches that won’t amount to anything. They’re much thinner; they stretch like crazy and form very long internodes but still have no chance of making the canopy. Their destiny is to remain in the shadows. So why keep them?

Week 7: Gorilla Glue Still Stretches Like Crazy

First female hairs on Gorilla Glue #4 after three weeks of 12/12

Gorilla Glue #4 progress in the third week of 12/12 © Growdiaries © Canadian

Three weeks into 12/12, Gorilla Glue was still focusing on the stretch rather than on producing the first flowers. (Although, those started to appear too—see the right pic above.) The gardener’s job was to raise the light a bit each morning. This was quite an issue because the other strains in the tent were nowhere near as tall.

And, unbelievably, the Gorilla Glue stretch continued for another two weeks until she reached a final height of 68 inches (1,73 m). Let’s have a look at the height chart of this GG4 from seed to harvest:

Gorilla Glue #4 Grow Journal and Week-by-Week Guide: Height chart

Height of Gorilla Glue week by week.

Week 8: Running Out of Headroom

A side view of a super cropped stretchy branch and a very stetchy indoor cannabis plant 4 weeks into flowering

Super cropping as the last line of defense against GG4 stretch © Growdiaries © Canadian

Four weeks into flowering, the stretch got so out of hand that several tops were growing straight into the light and getting burned in the process. The grower had to bend the tallest tops, using the super cropping technique.

To super crop means to crush a branch between your thumb and forefinger so that the branch can be bent in any direction, including downwards. This is a high-stress training (HST) method and is mostly used in veg for canopy management.

The gardener also suspected that he was feeding his Gorilla Glue too much nitrogen and micronutrients (which contributed to the stretch). So he stopped using both, and now the girl was receiving only those formulas that are needed in flower. Plus CALiMAGic.

Nutrients, ml/gal 6 7 8 9 10 11 12 13 14
CALiMAGic 4 4 4 4 4 4 4 4 4
FloraMicro 1.5 1.5 1.5 1
FloraGro 0.25 0.25 0.25
FloraBloom 3 3 3 3 3 3 3 3 3
FloraNectar Fruit-n-Fusion 2 3 3 3 3 3 3 3 3
Liquid KoolBloom 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

The feeding schedule for Gorilla Glue flowering stages.

Week 9: The Flowering Stretch is Over

A very stretchy weed plant with extremely long internodes and a closeup of an immature but frosty bud

Gorilla Glue stretch stopped in week 5 of 12/12 © Growdiaries © Canadian

As a high-stress technique, super cropping could have stressed Gorilla Glue and made her hermie, but that didn’t happen. She finally stopped stretching but reached a height of 68 inches (1.72 m) which is a nuisance for an indoor grow.

Even if your tent is tall enough, having a stretchy plant like this leads to lower yields. Here’s why:

  1. The lower bud sites are outside the effective range of the light.
  2. They are in the shadow of the above growth.
  3. The plant has diverted too many resources from budding to stretching.
  4. It spends too much energy on the transport of water and nutrients through too long branches.

For all these reasons, it’s in your best interests to minimize the stretch indoors if you can.

Besides lower yields, the quality of buds is also inconsistent in stretchy cannabis. While the top flowers get enough light to become fat and dense, the lowers are tiny and fluffy. They’re often referred to as “popcorn” buds.

Many gardeners remedy this by lollipopping (removing bud sites and leaves in the lower third of the bush). This redirects the available resources to tops making them even bigger and heavier.

This grower however preferred not to go down this road. He explained that he liked to push the levels of nutrients to the limit, and whenever he went overboard with feeding, the lower bud sites were the first to show signs of trouble. So he left them as an “overfeeding fuse”.

Having said this, we don’t think he ever got carried away with nutrients in this grow cycle (see the chart below). Some people up the doses to 1000 or even 1200 ppm sometimes and get away with it.

Gorilla Glue #4 Grow Journal and Week-by-Week Guide: TDS readings chart

TDS measurements for the whole Gorilla Glue diary.

Week 10: Getting Resinous and Smelly

Closeups of well-stacked and resinous marijuana buds 6 weeks into flowering

Even the base of fan leaves gets covered in trichomes © Growdiaries © Canadian

After the flowering stretch has finished, cannabis focuses on stacking up the buds and producing trichomes.

Trichomes (people often call them crystals) are tiny mushroom-like glands that cover the calyces as well as little leaves sticking out the flower clusters. Note that the most resinous of strains, such as Gorilla Glue #4, can have trichomes even on those large fan leaves that are NOT in contact with flowers (see the left pic above).

Trichs are choke-full of THC and other cannabinoids as well as terpenoids and flavonoids. The latter are responsible for the plant’s smell and taste. Naturally, when the plant starts to get covered in resin, it begins to smell too. In this grow, GG4 wasn’t the smelliest of the bunch, though.

Btw, the smell of buds depends on the temperature during flowering. When it’s too hot, flowers evaporate their terpenes at a higher rate which will result in a bland-smelling smoke. And it’s one of the reasons why you should lower day temps to something like 23–25 °C (73–77 °F). In this grow cycle, the temps were not quite ideal but at least consistent.

Gorilla Glue #4 Grow Journal and Week-by-Week Guide: Day and night temperature chart

Day and night temps for the whole Gorilla Glue timeline.

Week 11: Lower Buds Removed After All

Closueps of ganja flowers with lots of trichomes and most of the hairs still white

Gorilla Glue trichomes coverage is impressive © Growdiaries © Canadian

This point in the timeline marks a lull in your activities. You have dealt with the stretch, changed the diet to one suitable for flowering, dialed in all conditions. On the other hand, it is yet too early to start watching the trichomes for signs of approaching harvest. Fertigation remains your only chore.

The only other thing that the grower did for his Gorilla Glue at this stage was lollipopping. He decided that she’d be better off without lower bud sites after all.

Week 12: Sideways and Upside Down

Heavy maturing marijuana buds drooping under their own weight

Gorilla Glue flowering stages coming to an end © Growdiaries © Canadian

By this point in the timeline, you’ll probably start to anticipate your Gorilla Glue #4 harvest time. At least, the specs of the strain that you’ve seen on the product page tell you that harvest is near.

You can start by looking at the state of pistils. These “female hairs” sticking out of buds are white when they first emerge. But by harvest time, they change their color, most often to orange, but more exotic hues are also possible. Anyway, mature pistils also look twisted and dry which signals that your GG4 harvest is fast approaching.

A word of caution: Under an HPS light, pistils tend to look more immature. So inspect your plant under natural light too: the difference may surprise you.

When you see that the pistils are far along enough, you can start inspecting your Gorilla Glue trichomes under a hand microscope. But in this run, it was yet too early.

However, the buds were extremely resinous and so heavy that the branches were bending under the weight. It’s another reason not to let the stretch spin out of control. And when the damage is already done, at least provide some kind of support in the form of stakes, trellises, yo-yos, ScrOG net, etc.

Week 13: Got Milk? What About Amber?

A long conical cannabis cola almost ready for harvest with yellowing edges on fan leaves and a macro shot of trichomes

Gorilla Glue trichomes look almost ready but not quite © Growdiaries © Canadian

Now, when the pistils are all orange, twisted, and dry, it’s time to watch the state of the trichomes in earnest. Because it is them that will tell you if your Gorilla Glue is ready to pick.

You should harvest your Gorilla Glue at the peak of her potency which is easy to determine by the color of trichomes. When they are clear, it’s too early because they can produce yet more THC as well as other cannabinoids and terpenes. The presence of all these substances makes trichomes appear milky/cloudy. And this marks the perfect moment to harvest your buds.

Please bear in mind that the color of trichomes determines not only the potency but also the character of the high. After most or all of the trichs have become cloudy, a few of them will start to turn amber. Look closely at the macro shots above and below to see what we mean.

No amber means that your Gorilla Glue will produce a more heady effect. And the longer you wait and the more ambers you see, the more your Gorilla Glue will make you relaxed and sleepy. It’s because, in amber trichomes, THC starts to degrade to cannabinol which doesn’t so much warp your mind as sedates you.

Mostly clear trichomes will produce a high that is felt mostly in the head and without much body buzz, but it can make you paranoid and can be weaker compared to more mature buds.

The state of the trichomes will also tell you when to flush Gorilla Glue. It all depends on the medium you grow in because, in hydroponics and soilless mixes, such as coco, it only takes one week to flush. In soil, you may need as much as two weeks. So we suggest starting the flush in soil when the first cloudy trichomes appear. In coco and similar mediums, you may start flushing when most of them are cloudy or even when you see the first ambers.

Week 14: Gorilla Glue Harvest

A perfectly mature green marijuana cola and a macro shot of Gorilla Glue trichomes, most of them cloudy and a few amber

After 10 weeks of 12/12, it’s Gorilla Glue #4 harvest time © Growdiaries © Canadian

As we said earlier, in the last week or two before your Gorilla Glue harvest, you should give her nothing but pH’d water. This will give her a chance to uptake the remaining chemicals from the medium and use up those that were already in her system. After a proper flush like this, the smoke will be pure, tasty, and smooth, the joint won’t need relighting, and will leave snow-white ash.

If you dry your cannabis in the same tent, you can cut the plant as a whole and hang it upside down. Make sure to control the temperature and relative humidity. They should be the same as during the Gorilla Glue flowering stages. Another important thing is darkness, and you should probably leave the oscillating fan on.

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The initial drying usually takes anywhere from 5 to 10 days depending on the conditions. The longer it is, the better (potentially) the quality, but watch out for mold. You can slow down the process by wet-trimming both the fan leaves and the “sugar” leaves because this would drastically reduce the evaporation surface.

When the surface of the buds is dry to the touch, try to bend the branch. If it snaps, it’s time to cut the nuggets from the branches and put them into glass jars for curing.

Curing serves not only to slowly evaporate the remaining water from flowers. It also gives them time to degrade chlorophyll, sugars, starches, and other organic compounds. You don’t want all those in your smoke because they make it smell like hay, taste terrible, and cause coughing.

Gorilla Glue takes at least 3 weeks to cure properly. This may include the week or so of drying and another two in the jars. However, chemical reactions don’t stop after 3 weeks, and you may find the buds taste better and better the longer you cure them. Curing also makes Gorilla Glue more potent.

The End Result

A weed branch with round compact nugs, yet untrimmed and very frosty, lying next to a pair of garden shears

Gorilla Glue #4 yield per plant is quite impressive at 159g © Growdiaries © Canadian

For this Gorilla Glue #4, harvest time was a happy time because buds were big, very dense, and thus massive. The grower harvested 159 g (5.62 oz) from just one of 3 plants grown under a 400W HPS. The overall yields per watt for GG4 and other plants in the tent were through the roof.

The grower noted an extremely potent high once the buds were cured, and the earthy and flowery smell produced a combination that was hard to describe but very pleasant.

We have analyzed GG4 yields in other grows too and compiled them in a table:

Yield per Plant Weeks, Total Weeks in Flower Type of Light Wattage
53g (1.87oz) 16 10 LED 450
92g (3.25oz) 24 9 LED 400
45g (1.57oz) 12 7 HPS 400
38g (1.34oz) 14 9 LED 400
100g (3.53oz) 14 7 HPS 400
31g (1.1oz) 13 8 LED 340
129g (4.55oz) 18 9 LED 300
76g (2.68oz) 13 7 LED 280
164g (5.78oz) 19 9 LED 340

As you can see, on average, Gorilla Glue #4 yields 81g (2.85oz) per plant after 8.3 weeks of flowering. Gorilla Glue #4 veg time depends on the setup and growing methods, and in our sample, the whole life cycle takes from 12 to 24 weeks, with about 16 weeks on average.

Main Takeaways From Gorilla Glue #4 Grow Journal

Gorilla Glue genetics is strong, vigorous, and easy to grow. This strain doesn’t take long to flower, but you might come across a stretchier (and longer) GG4 phenotype. In this case, we recommend shorter veg.

You can get away with feeding your Gorilla Glue 4 higher doses of nutes, but the nutrient schedule doesn’t need to be very sophisticated to get good results (as we’ve seen in this GG4 grow diary). She’s also a very thirsty variety.

The smell isn’t overwhelming, but you’ll still need a good carbon filter during flowering stages. Gorilla Glue #4 responds well to any high-stress training methods and yields way above average.

As for the quality, the buds have a very complex and nuanced flavor that is not so easy to describe, and the smoke is insanely potent. But it’s what you may expect from one of the most resinous genetics out there. Happy growing!

All images in this post were taken from GrowDiaries, the world’s largest weed-growing community.

Cannabis Seedling Problems: How to Resolve Any Issues

Newbie growers tend to run into cannabis seedling problems with their plants from day one. That’s why our diagnosis tool can come handy to you. Start by finding your cannabis seedling issues in the list below (we tried to group them for more convenient navigation), and then use page jumps (or scroll down) for possible causes and solutions.

It may be a serious disease, or just a temporary issue that is easy to fix, or even a perfectly normal thing that you mistook for a sign of trouble. In the latter case, we recommend you to read our article on the anatomy, development and look of a healthy seedling. And, of course, it’s better to ensure that no cannabis seedling problems arise in the first place, so we encourage you to read another article with tips on creating perfect conditions for your sprouts and caring for them the right way.

Symptom Possible Cause/Remedy
weed seedling won’t shed shell see Removing the ‘Helmet Head’ by Hand
weed seedling not opening see Removing the ‘Helmet Head’ by Hand
or
The Problem of Weed Seedling Damping Off and Other Root Problems
marijuana seedling too tall
weak/thin stem
seedling bending/falling over
see Seedling Stretching: Reasons and Solutions
cannabis seedlings keep dying
seedling sprouted but not growing
seedlings not growing true leaves
see The Problem of Weed Seedling Damping Off and Other Root Problems
cannabis seedling very short see The Problem of Weed Seedling Damping Off and Other Root Problems
or The Seedling Gets Too Much Light
weed seedling limp see Water Stress (Overwatering / Underwatering)
or The Problem of Weed Seedling Damping Off and Other Root Problems
leaves light green and going yellow
marijuana seedling leaf tips turning brown
see Cannabis Seedling Problems with Nutrients
marijuana seedling turning yellow see The Seedling Gets Too Much Light
leaves turning white / bleaching see The Seedling Gets Too Much Light
or Cannabis Seedling Problems with Nutrients
yellow veins or seedlings yellow in middle
white / red / purple / brown stem
purple leaves/veins
see Discoloration Isn’t Always a Sign of Trouble
marijuana seedling dark green see Cannabis Seedling Problems with Nutrients
leaves pointing up
seedling cupping/praying
leaf edges curling up
see Heat Stress is Common Among Cannabis Seedling Problems
leaves pointing/curling down see Water Stress (Overwatering / Underwatering)
or Wind Burn
wavy leaves see Water Stress (Overwatering / Underwatering)
deformed/twisted leaves see Weed Seedling Mutations
cannabis seedlings eaten / uprooted / broken etc. see Physical Damage: When a Seedling Can and Cannot be Saved?

Removing the ‘Helmet Head’ by Hand

Too often, when a weed seedling is sprouting from the medium, the cotyledons are still stuck in the shell and it won’t come off on its own.

This is day 1 for three OG Kush Auto seedlings. Only one of them has cast off its shell on its own.

Probably, most seedlings will find enough strength to eventually shed the shell, but meanwhile a lot of time will be lost and you’ll see a lot of stretching. So you have to remove the shell yourself as soon as possible. Moisture is the key here. If the seedling is still tiny and can be covered by moist medium, by all means do so. Probably it will be enough. If not, the shell will be wet enough in a couple of hours, so that you can easily remove it with your fingers.

If the seedling is already too tall to be covered with wet soil, spray it with water or put a droplet of water on the shell: this will make it wet and mushy after a while. Then remove the shell with your fingers.

We’re wetting the shells with a drop of water. It will be enough to easily remove them from cotyledons.

Sometimes the shell comes off, but a thin membrane covering the cotyledons remains. Usually, it’s the reason why weed seedling is not opening. The membrane is too dry and acts as a straightjacket. Make it wet and when it gets soft, pluck it with your fingers. It usually slips off quite easily.

pot seedlings no shell film

We have removed shells from the seedlings on the right and in the center. The one in the center still retains the membrane.

Warning: Sometimes, the seedling hasn’t rooted too deeply and has still a very short tap root (like an inch or so). In this case, the procedure described above can result in your plucking the sprout out of the soil completely. So never apply excessive force. It’s better to make the shell wet again and wait a bit more. If you did pull the sprout out of the ground, you can still stick it back in (probably, it’s best to remove the shell first). Most seedlings can survive this without apparent shock or stress.

In your future grows, make sure that sprouts emerge from the medium already without a shell. Keep the surface of the medium moist at all times, and you probably should think about placing the seed a little deeper than you did before. In this case, the seedling will encounter more resistance on its way up and the shell will slide off.

Seedling Stretching: Reasons and Solutions

Most seedlings are tall and skinny and look vulnerable, and generally it’s not a problem. But sometimes the stem is growing too tall, weak and thin and can’t support the weight of cotyledons anymore. As a result, the long stem is not growing straight, but sideways or even upside down. The reason is simple: there’s not enough light. Either the source is too weak (e.g. you keep your seedlings on the window sill), or the light is placed too high above. In either case, seedlings stretch toward light uncontrollably and keep falling over.

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We still recommend that you play it safe the first couple of days and keep the light at a distance. Let the seedling reach the height of 2-3 inches (5-7 cm) – it’s normal and healthy and much better than the other way around: when the sprout is stressed by too much light (and sometimes heat). Slowly correct the distance before you see the seeding bending, leaning or even falling over. In time, you’ll know the exact distance for your type of bulb.

stretchy seedling

This seedling has clearly stretched too much and needs to be made shorter. Strart by crushing its stem with your fingers just above the surface of the soil and then do the same in several places above.

But what to do if a seedling already bent and flopped over? You can always use a toothpick to prop a weed seedling not standing up. However, it is best to make the stem that is too long shorter. You can do this by adding more soil (or coco, or other medium) – then the part of the stem that you cover by the medium will grow more roots, and it’s great. Or, if the container isn’t tall enough for that, you can press the seedling to the soil horizontally (it’s easy when the stem is already bent or the seedling fell over) and cover it with a thin layer of soil. If there’s too much resistance, gently crush the stem with your finger tips, probably just above the surface – it won’t really hurt the seedling.

stem crushed

Now that the stem is soft and pliable, lay it on the soil, probably in a half-ring shape.

covered with soil

Now cover the bent stem with soil and don’t forget to water. Note that this procedure will slow down the growth a bit, compared to seedlings that you didn’t let stretch in the first place.

The Problem of Weed Seedling Damping Off and Other Root Problems

Stunted growth, or slow growth, is common among cannabis seedling problems. The reason can be anything: from wrong conditions to stress to shock, but here we’ll talk about problems in the root zone. Healthy root growth is the single most important factor for a plant’s well-being, and if you see that your marijuana seedling stopped growing or is growing very slow, or especially if cannabis seedlings keep dying on you time after time, the first thing to check are the roots and what’s going on with them. Are they affected by some type of fungus? Is there root rot?

Most of the time, these problems arise when the medium is constantly wet and cool at the same time. These are ideal conditions for mold and fungi, and can lead to the weed seedling damping off. Apart from the seedling not growing leaves or its slow growth in general, you will notice that the stem gets very thin just above the surface. Next thing it will flop over. And, of course, you may notice some whitish substance on the surface of the soil. When the soil feels damp and cold to the touch, it happens very often. And the problems are not just on the surface, but more importantly deep down, too.

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Cannabis Seedling Problems Can be Caused by Bugs

Another reason why a seedling has sprouted but is not growing is that some kind of bug living in the soil has eaten the tap root. You wonder why the seedling won’t grow without realizing that there is in fact nothing at all below the surface, no roots to speak of. This sprout will die, and there’s nothing you can do about it. To prevent this from happening in the future, kill all the parasites in the soil with heat. Just make the soil wet and place it into the oven at around 200° F (90-100° C) for a half hour or so.

A Root-Bound Seedling is Hardly Ever a Problem

Some novice growers wonder if a cannabis seedling can become root bound. It’s the situation when there is too little room in the medium, so that the roots reach the sides of the container and start to grow along them, simply because they have nowhere else to go. It’s quite a common situation for mature plants growing (or shall we say ‘not growing’?) in too small pots, but seedlings generally haven’t enough time for their roots to use up all available space. So seedling becoming root bound is hardly ever an issue.

And, of course, if you feel that your marijuana seedling is growing slow or not growing fast enough for you or is very short, make sure that you don’t expect too much. Read about the healthy and normal seedling development here.

The Seedling Gets Too Much Light

Most marijuana growers would swear that the more light the better. However, the issue of too much light is the real thing, especially for weed seedling. We have been sent countless pictures of seedlings showing the signs of stress from too much light. To be frank, we sometimes (erroneously) diagnosed the issue as potassium (K) deficiency which is often manifested by the lower leaves turning yellow at the edges. However, if you see this symptom in sprouts, the first thing you should suspect is that you have a source of light that is too intense or too close.

You may ask why then this symptom (yellow spots along the edges) appears not on the topmost leaves, but on the lower ones? Well, it’s because the lower leaves have had more exposure to the stressful levels of light (simply because they are older and have been around longer). Leaves yellowing due to too much light are very rare if you use CFL or T5 lights, but with HID (high intensity discharge) bulbs, like HPS or MH, or with the LED technology, these problems are very common.

Too Much Light and Heat Stress Often Go Hand in Hand

If you see seedling leaves turning white, sometimes to the point of complete bleaching, it also can be caused by too much light, but also made worse by heat stress (see below) and maybe calcium deficiency (these two often come hand in hand). Remember that for plants grown in coco calcium deficiency is especially common.

Another sign that your light is simply too much for this stage is that the seedling stays very short. It not only has no reason and motivation to stretch toward the bulb, but the dense flux of photons is constantly pounding on it, causing it to keep close to the ground.

If you see any of these signs, simply raise the lights, or use weaker ones.

cannabis seedling problems: too much light

This seedling was exposed to the harsh light of a LED bulb for too long. That’s why its cotyledons and the first pair of true leaves look yellow, dry, and brittle.

cream caramel seedling too much light

Another severe case of too much light. Again the culprit is a LED bulb that was kept too close to the seedling.

cannabis burnt by too much light

These two plants stand next to each other under two CFLs each. There’s clearly something wrong with their lower leaves. Our guess is they have received too much light. See how compact and dense they are.

Cannabis Seedling Problems with Nutrients

When you see a yellow leaf on your seedling, it’s not necessarily the symptom of too much light (as described above). It can also be a nutrient deficiency. It is seldom the case in soil, because soil mixes come preloaded with fertilizers, organic or synthetic, and it’s enough for the first two weeks or so. But if you use some sterile medium like coco or rockwool, it’s your job to provide your seedlings with plant food. Unfortunately, it’s more than easy to make mistakes here.

pot seedling nitrogen deficiency

This seedling looks yellow and sickly. Most probably, it suffers from many deficiencies, including N deficiency. Note that the medium here is coco. In soil, you can give your seedlings only plain water and still see no deficiencies whatsoever.

Read carefully the instructions for your nutrients formula and follow them, not forgetting to adjust the dosage for various stages. Look at the color of your seedling: its leaves should have a healthy and vibrant green color. If leaves are light green or yellowish or you see yellow cotyledons, it could be nitrogen (N) deficiency. Although sometimes, if you overwater your young plants for days and weeks, they can show the same symptom (but there will also be others, more specific; see below).

If the seedling is dark green, it looks more like N toxicity (too much nitrogen). In severe cases, seedling leaves will also be curling down.

cannabis seedling issues: nitrogen toxicity

If you see such deep, dark green color of the leaves, probably you’re feeding your plant too much nitrogen (N).

nitrogen toxicity or wind burn

This is how nitrogen toxicity can look in a mature plant. Also check if it’s not a wind burn (if there isn’t a fan too close to the plant).

We already mentioned seedling bleaching and white spots while discussing the problem of excessive light, and mentioned that it could be caused or made worse by calcium deficiency, most common in coco.

And surely there is this widespread symptom of leaf tips turning brown which is a sign of nutrient burn. It simply means that the dosage of fertilizers that you give your plants when watering (or that is present in the soil mix) is way too high, and you should lower it when you see your seedling burn like this.

Discoloration Isn’t Always a Sign of Trouble

When you suspect that the color of your seedling is not quite normal, maybe you’re wrong. Of course, yellow hues should always raise a flag. The exception is when you look at a plant the first thing in the morning and see yellow in the middle of uppermost young leaves or yellow veins. It could simply mean that this is the new tissue that has grown in the dark and simply hasn’t had a chance yet to be filled with green chlorophyll. Expose it to light, and it’ll become green in no time.

Stem color can vary from plant to plant. It can be white, red, purple, and sometimes even brown. If there are no other worrying signs, it’s probably natural and caused by the specific genetics. Purple stem, veins, or whole leaves can also be due to colder night temperatures (in genetically predisposed strains). So when your seedling is turning purple, see if it doesn’t get too cold at night.

Heat Stress is Common Among Cannabis Seedling Problems

If your weed seedling experiences heat stress, it affects the shape of leaves in a very specific way. You may see the leaves pointing up.

Back in the day, we used to keep CFL bulbs too close to the seedling, and, instead of shying away from it, the seedling seemed to try and hug the bulb with its upper leaves. Other growers see it differently: to them it seems as if the seedling were praying. Still others name it ‘cupping’.

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The underlying cause is the same though: not able to move away from the light, the seedling tries to position its leaves in such a way that the light falls on them only obliquely. This helps them absorb less heat energy. If you continue to expose your plants to heat (be it hot air, or the energy from the light), you’ll see a more sinister symptom: leaf edges curling up. The heat often aggravates calcium deficiency and vice versa.

To combat this problem, always try to maintain the correct temperature range in your grow room and make sure the light isn’t close enough to burn. The ‘backhand test’ can help you with that. Place your hand palm down under the light at the level of plant tops and hold it there for some time. If you feel the light ‘bite’ or there’s any discomfort, it’s best to raise the light.

marijuana seedling leaf edges curling up

If leaves on your cannabis plant (at any stage) curl up like this at the edges, it means they are overheated by light or hot air.

cannabis seedling problems: the plant top touched the light

This young plant kept under a CFL has grown so fast overnight that it actually touched the bulb. Hence the burned leaves on top.

Water Stress (Overwatering / Underwatering)

Newbies overwater marijuana all the time. Luckily, the plants have a way of showing their caregivers that they overdo the watering. The first sign of overwatering is clawing of the leaves, of their curling down. When you touch the leaves on an overwatered plant, you’ll feel that they are quite rigid. Conversely, if the leaves are pointing down, but feel limp and lifeless, the seedling is probably underwatered.

overwatered cannabis seedling

Leaves on this seedling are shriveling up and curling down. The plant has clearly been overwatered. At the same time, it shows signs of heat stress.

Leaves can even change color because of water stress. If you keep them overwatered for long periods, they’ll begin to yellow and eventually die off. The bottom line is: when you see marijuana seedlings shriveling up, correct your watering schedule.

marijuana seedling problems: chronically overwatered plant

This chronically overwatered cannabis seedling has leaves that look yellowish and lifeless along the edges, almost as if they were touched by frost.

Sometimes, weed seedlings have wavy leaves. We don’t know the exact reason why it happens, but have this theory that the issue is due to irregular watering. No one has yet disproved this theory, and we continue observations. In any case, it’s not a grave symptom. Seedlings with wavy leaves may not look fit for a beauty contest, but are otherwise healthy and vigorous.

marijuana seedling wavy leaves

All of these seedlings have wavy leaves: a not uncommon symptom. Probably, at some earlier point, the grower has overwatered these plants.

Wind Burn

Another reason weed leaves can become deformed is when there is strong wind blowing on them all the time. For instance, you may have placed a fan close to a seedling, and it’s blowing straight at it and not above it. After a while, it may cause wind burn. Leaves that are stressed this way are pointing down and forming ‘claws’ similar to overwatering. But in this case, they also curl at the edges in the shape of tubes. Often, they also have dark green color, like they do when there is too much nitrogen in their feed.

Weed Seedling Mutations

Deformed, twisted, shriveled leaves – these symptoms can appear in marijuana seedlings for no reason and should be considered mutations. These plants are never the best specimens in terms of growing, but, if you bring them to harvest, the smoke may surprise you. It’s up to you to choose what to do with mutants. Seeds don’t come cheap, and you may decide to grow every one of them. That said, breeders always discard seedlings with leaves twisting, as well as with other mutations. There is one interesting mutation though that we personally wouldn’t mind to keep and propagate: weed seedlings with 3 leaves. Usually, leaves grow in pairs, opposite each other on the stem. But here you have three leaves growing from every node. Delightful!

cannabis seedling problems include mutation

Twisted leaves point to some kind of mutation. You can still succesfully bring this plant all the way to harvest, but it’s not the genetics that you’d want to keep.

marijuana seedling with 3 leaves

A rare and cool-looking mutation: a cannabis plant with 3 leaves.

Physical Damage: When a Seedling Can and Cannot be Saved?

A special case of seedling problems is when a grower damages it by mishandling. A seedling can be knocked over and uprooted. If you don’t disturb the root system too much, the more vigorous sprouts can survive the repotting without even slowing down their growth.

Root damage is a bigger issue. It often happens during transplant when a piece of soil falls off, tearing off a part of the root ball in the process. You just put the rest back in soil, and hope for the best. When the root broke, it’s a significant stress for a seedling, so try to make its life for the next couple of days less stressful. You can do this by creating milder conditions, like light and temperature, and, of course, refrain from any major changes (repotting, switching to 12/12, or moving outdoors) until the damaged seedling resumes its growth.

And what if the stem broke? Partially broken stem can heal, no doubt about it. Just make a splint and put a bandage where the seedling snapped, and the tissue will not only heal, but even be stronger. Even if you break the stem clean off, it arguably can be made whole again in this way.

What you can’t do is make any use of a seedling that only consists of the roots and the stem, but no growing point, in other words no leaves, as when something has eaten them. The thing is that cannabis doesn’t grow from roots. There are simply no growing points there, so you can’t salvage such seedlings.

Say Goodbye to Cannabis Seedling Problems!

Most cannabis seedling problems can be resolved, and quite easily, too. Just don’t freeze with panic and use common sense. After all, there’s nothing magical about cannabis. It’s just a plant, and one that is quite hard to kill. And if you fail to save a particular seedling, learn not to repeat the same mistake next time.


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