8 Tips for Growing Jack Herer Cannabis [Guide]

When it comes to growing your favorite marijuana strain at home, it’s well-advised you follow the advice of experts as much as possible. The steps and tips they offer can be the difference between complete failure and glorious, trichome-coated success. After all, those beautiful nuggets that you see in dispensaries don’t just pop off of weed plants by sheer circumstance – there is plenty of method to the madness.

Wondering how to grow Jack Herer? In this step-by-step guide, we explain how to cultivate nugs that would make the Emperor of Hemp himself proud…

Unfortunately, the bad news is that even for experienced growers, Jack Herer strain is usually one that’s viewed as a pretty big challenge. In other words, it can be notoriously difficult to grow. The strain is of course named after legendary marijuana activist Jack Herer, best known for his book The Emperor Wears No Clothes. In it, he illustrates the ludicrousness of cannabis prohibition and outlines the many uses of hemp. The book has inspired a number of other important activists, including cannabis kingpins like Ed Rosenthal and Steve DeAngelo.

This classic strain was developed in the Netherlands in 1994, where it was cultivated as a medical-grade strain. Genetically, it is a cross of indica Northern Lights #5, Shiva Skunk, and a Sativa Haze hybrid. It is a unique strain that has seven High Times Cannabis Cups awards and is a slightly sativa-dominant hybrid. Its THC content can reach 23%, which means it should be respected and also that is probably not the right option for new users.

Jack Herer offers a vivid and euphoric high that lifts your mood but should not overpower experienced users. The cerebral high, coupled with a boost of energy that ensures you’re not threatened by couch-lock, makes this an excellent party strain. It also contains up to 2.2% CBG, which is unusual in terms of other marijuana strains. Jack Herer tends to be used for medicinal purposes, especially if you suffer from migraines, PTSD, or depression.

In this growing guide for Jack Herer, we outline eight tips to help you honor the memory of a legend.

Growing Jack Herer Tip #1 – Try a 12/12 Lighting Schedule

Although we don’t necessarily recommend this tip, it has been used effectively by thousands of growers. Typically, it is best to get as much light as possible during the vegetative stage. While a lot of growers try to get 18 hours of light a day, some expose their marijuana plants to 24 hours of light. When the plant is ready for flowering, you switch to a 12/12 lighting schedule.

When grown correctly, Jack Herer plants can be absolutely huge! We’re talking ‘too big to fit in an indoor grow room’ here. If space is tight, restrict your plants to a two-week vegetative stage and go straight to flowering. It is not something you would normally do, but it IS a viable way to grow Jack Herer from seed.


Remember, the majority of sativas are equatorial, which means they are rarely exposed to more than 12 hours of light in a day. When you go straight for the 12/12 schedule, your Jack Herer plants will develop an enormous central cola with little in the way of side branching. Bear in mind that approximately 85% of the plant’s weight is in the main cola, and side branches produce smallish buds.

If you grow Jack Herer in this manner, its open structure will enable the lower branches to produce nice buds. Admittedly, you will end up with lower yields and smaller plants, but when you remove the vegetative stage, you benefit from more annual harvests.

Growing Jack Herer Tip #2 – Remember, Yield Varies Depending on the Phenotype

As Jack Herer is such a unique strain, it offers different yields depending on the phenotype, and this is a strain with numerous phenotypes. While sativa-dominant is the most common phenotype, there are also indica-dominant versions available. You will experience greater yields with indica phenotypes because its sativa counterpart usually only offers low to moderate yields.

When grown indoors, you can get up to 18 ounces per square meter planted. Outdoors, you could get up to 18 ounces a plant, and it should be ready for harvest in late September. We spoke to a grower who outlined his yields when using the 12/12 lighting schedule from the very beginning.


He grew five plants and ended up with 14 ounces. The biggest issue was the difference in yield size between plants, which was enormous due to the different phenotypes used. While the poorest performing plant offered a little above two ounces, the largest one offered four ounces.

At one point during the cycle, he was unable to feed the plants properly and this certainly affected yield. The problem of Jack Herer growing too fast also reared its head at this stage because the plants sped towards the lights and were stressed as a result. The plants also blocked the airflow of the fan, so we would expect better yields overall when Jack Herer is tended to constantly.

“While the poorest performing Jack Herer plant offered a little over 2 oz of bud, the largest one offered more than 4 oz.”

Growing Jack Herer Tip #3 – Don’t Underestimate Flowering Time

Jack Herer’s flowering time is 8-9 weeks on average, but it can be significantly longer in some cases. The first couple of weeks are crucial because it can take more time than expected for your plants to begin growing in earnest. As we’ve already mentioned, the vegetative stage can be finished as soon as you’re ready to change the light schedule. Just give the plants two weeks in the vegetative stage and get ready to force them into flowering.

Once your Jack Herer plants get their pre-flowers, they can grow as high as 16 inches within a couple of weeks. At this delicate stage, make sure you are checking the lighting every day because these plants really grow once they get moving! By the third week of flowering, you may need to remove some branches on the lower nodes to ensure lower buds get enough light.

By the time the flowers are growing, the plants could be three feet tall. It is also possible that one of your plants will grow much faster than the others. If this happens, super-crop it to even up the canopy. By the middle of the flowering stage, it is probably a good idea to upgrade your lighting, because these babies need it.

During the last few weeks, the plants will start growing out and producing plump, hard, and hopefully large buds. Most Jack Herer plants grow to four feet indoors. As always, wait until at least 70% of the pistils change color before harvesting.

Growing Jack Herer Tip #4 – Consider Side Lighting for Your Jack Herer Grow

If you elect to grow your Jack Herer using a 12/12 lighting schedule and are concerned about low yield, you could look into adding side lighting when growing indoors. As you can probably guess, it involves lighting the sides of the crop rather than the top. In theory, it should work well because marijuana plants have a triangular shape when grown outdoors because of how natural light exposure works.

The sun rises low on the horizon, beams directly down at around midday, and drops away again. The problem is, side light assumes that weed grown indoors will react in the same manner. In reality, natural selection is extremely versatile. Cannabis is programmed to ‘die’ once it has finished its duty. In this case, success is when a female plant is pollinated, develops seeds, and propagates. When it isn’t pollinated, it gets sexually stressed, which results in fatter buds.


As you probably know, female weed plants shoot their flowers as high as possible to boost the chances of pollination. The top and outer buds receive preference. Training techniques such as topping help produce two main colas. Therefore, if you only use side lighting, your Jack Herer plants will have large and fat top colas, while the interior and lower buds will remain small. That’s how cannabis grows, and side lighting doesn’t alter this behavior.

“If you only use side lighting on your Jack Herer grow, the plants will have large and fat colas while the interior and lower buds will remain small.”

If you add side lighting to your regular lighting, you could benefit from a 20% increase in your yield. However, you have to be in full control of your growing environment for side lighting to be effective. It is also worth trying training techniques rather than opting for side lighting.

Growing Jack Herer Tip #5 –Training Techniques

The goal of training techniques when cultivating bud is to maximize horizontal growth and break the main stem dominance to ensure more buds are exposed to light. When done correctly, these techniques can result in even bushier Jack Herer plants with more colas. Here is a quick overview of three such training techniques:


Low-Stress Training (LST)Bend the shoots outwards and away from the plant’s main stem. Most growers choose to bend their plants into a cannabis bush, although experienced cultivators like to get creative.
Screen of Green (SCROG)You add a screen close to your lights and train the tops of the plants to increase the number of buds that are exposed to light. Typically, you add 30 cm of screen for every plant. Once your plants grow through the screen, pull them back down and tie their branches to the screen. You can also remove large fan leaves to ensure your buds receive more energy.
Topping This is the process of pruning the main stem’s growing tip. This is a high-stress training (HST) method. When you remove the terminal bud, you boost the growth of two new colas and also increase the growth of branches lower down on the plant. Make sure you use clean scissors to perform the cut of the main stem’s tip.

Growing Jack Herer Tip #6 – The Best Nutrients for Feeding

Fertilizers have a standard N-P-K reading on the front of the packaging which tells you the ratio of Nitrogen (N), Phosphorus (P), and Potassium (K). Typically, marijuana plants need more nitrogen during the vegetative stage and more of the other two nutrients when flowering.

Jack Herer is a little different because it isn’t a ‘leafy’ plant. As a result, it needs less Nitrogen than other plants overall. A fertilizer with a 3-3-5 ratio works well as the buds get bigger. Overall, however, there isn’t a strain-specific nutrient when growing any marijuana plan; it is simply a case of requiring more or fewer nutrients for optimal growth.

Although the focus is on NPK, it is a mistake to neglect other important nutrients such as Sulfur (S), Calcium (Ca), and Magnesium (Mg). Very few growers, especially first-timers, ever have to worry about nutrient deficiency. Nutrient burn on the other hand (the process of providing plants with too many nutrients) is a significant problem. When you purchase fertilizer, use as little as 25% of the recommended dosage and work your way up.

“Contrary to popular belief, nutrient burn is a much more realistic problem than nutrient deficiency for first-time Jack Herer growers.”

Growing Jack Herer Tip #7 – Flowering Outdoors

As we mentioned above, Jack Herer is a monster when grown outdoors as it becomes enormous when it isn’t confined to an indoor grow room. The main issue is finding the right growing conditions. For the record, Jack Herer prefers to grow in a moderate climate with temperatures between 70 and 85-degrees Fahrenheit.

If you’re fortunate enough to live in such a location, you benefit from having to provide a much lower level of input than your indoor counterpart. You can expect your Jack Herer plant to begin adjusting to daylight changes as nature intended. Ultimately, they should be able to flower by themselves because, as the days become shorter, the plants are exposed to enough darkness to switch into the flowering stage.

If you plant Jack Herer at the wrong time, or else the weather is unusually good with longer days, you may have to take matters into your own hands. Of course, if you have the patience, you can support as much vegetative growth as possible. However, you have to be careful because, when the weather gets colder, your plants will not thrive.

If you need your plants to flower outdoors quickly, you can use a polyethylene sheet to block out sunlight or even build a screen in the right part of your garden. Remember, your plants need 12 hours of continuous darkness for 1-2 weeks in order to enter flowering mode.

Growing Jack Herer Tip #8 – Keeping Pests at Bay the Natural Way

Although indoor growers are not immune to the issues caused by pests, outdoor growers need to be more vigilant. No one wants to spray their plants with pesticides, but fortunately, there are innovative ways to ensure pests don’t wreck your crop without adding chemicals to the equation.

Option #1 is to introduce natural predators that can handle the pests on your behalf. Aphids, spider mites, mealybugs, and whiteflies are just some of the insects that can destroy all your hard work. As you surely know, there are lots of creatures in the animal kingdom that prey on others.

For example, ladybugs are great because they either kill or repel lots of pests and they don’t feast on your marijuana plants. Introduce a few into your garden and marvel at their effectiveness. Ladybugs are also beautiful creatures, which is a nice bonus. They are especially useful if you have issues with spider mites.


If you don’t like the idea of adding more creatures to your garden, why not try companion planting instead? There are a number of plants that act as pest repellents; you just need to plant them close to your weed plants. For instance, garlic cloves keep potato bugs, beetles, spider mites, and aphids at bay. Occasionally, animals such as deer and rabbits will arrive to munch on your plants, but guess what? They also hate garlic!

DID YOU KNOW: Planting garlic cloves next to your Jack Herer crop can help keep potato bugs, beetles, spider mites, and aphids at bay?

Flea beetles are a major problem for some growers. To combat this issue, introduce a hint of mint! As well as providing a gorgeous and refreshing scent, mint does a fantastic job of repelling flea beetles, a host of other insects, and mice.

If you love flowers, plant some marigolds and geraniums in your cannabis garden. Some growers place geraniums in pots to make their lives a lot easier. One of the benefits of marigolds is their speed of growth. You can plant them in the soil and within days they can produce a strong scent that keeps pests away.

We hope you enjoyed this guide, and that all of the tips prove useful if and when you elect to grow Jack Herer.

[Have any input or firsthand experience with growing Jack Herer? Make sure to comment below!]

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