8 Tips for Growing Blackberry Kush Cannabis: Grower’s Guide


When you grow your favorite strain, it is heartbreaking to discover that your end product looks nothing like what you’ll find in a dispensary. Our guides offer steps and tips to help you get closer to the top shelf bud you crave. Today, we feature a growing guide for Blackberry Kush, an indica dominant hybrid that is a cross of Blackberry and Afghani.

It is a strain known for its fruit flavor along with the famed earthy Kush taste. It is an extremely popular medicinal strain, and with a THC content of between 16% and 20%, its potency is to be respected. Depending on how you cultivate this strain, you will probably end up growing a different Blackberry Kush strain to what you see in the store; although not necessarily a lower quality version.

Tip #1 – Blackberry Kush Strain Review: What to Expect When You Use It

It doesn’t take long for users to discover why Blackberry Kush is such a coveted medicinal marijuana strain. Its sweet aroma is extremely noticeable, and you will definitely continue smelling it long after the weed has left the room. Your mouth will water as you smell this pungent bud, and the strong earthy diesel flavor, with a strong berry taste, will leave you craving more.

Although its THC is in the medium range, it is a strain known for having potent effects. You should consider using it if you suffer from anxiety. Once you smoke it, prepare to relax and lie down on a bed or ease into a comfortable position on your sofa; you won’t be getting up anytime soon. Blackberry Kush is an excellent stress-relieving marijuana strain with sedative qualities that should be used at night time.

Tip #2 – Difficulty Growing Blackberry Kush

The grow difficulty of Blackberry Kush is classified as ‘moderate.’ This is primarily because of its susceptibility to fungus and spider mites. Mites, in particular, can pose a real threat, even in an indoor grow. Although spider mites are not that hard to see, these critters have an incredible ability to multiply.

Most infestations begin from the accidental transfer of a small number of mites from another plant. These pests have also developed significant pesticide resistance over the years. Growers can reduce the number of spider mites in a cannabis garden by misting the plants with a homemade solution. Increasing humidity also works, but if you overdo it, fungal diseases could become a new issue.

One natural method of eliminating spider mites is to introduce predatory mites such as Phytoseiulus persimilis, Amblyseius fallacius, and Amblyseius californicus. All of them are capable of massively reducing an infestation by feasting on spider mites while leaving your crop untouched. However, these predators only survive in certain conditions and are usually ineffective when the humidity is under 60% and the temperature is over 86 degrees Fahrenheit. Alas, spider mites continue to thrive in those conditions.  

Tip #3 – Best Growing Techniques for Blackberry Kush

If you want to make the most out of your Blackberry Kush crop, use the Sea of Green (SOG) method. SOG involves growing several small plants rather than a handful of huge ones. You can bring the plants to harvest faster because your smaller plants don’t need to support as many bud sites as large plants.

Typically, growers switch to the flowering stage when their plants are no more than 4-6 weeks old when utilizing the SOG method. We recommend adhering to the longer side of that range because an extra week of vegging can make a massive positive difference to your yield. You can also ‘top’ your seedlings by getting rid of their tips when they have 4-6 pairs of leaves.

Make sure you have at least four plants. Begin as usual by growing your plants from seeds or clones. Allow them to grow and transport them into larger buckets when necessary. About two weeks later, use the Low-Stress Training (LST) method which involves gently bending the branches down, so they sit flat rather than reaching upwards.

Once you are satisfied that your plants have had enough of a vegging period, force them into flowering by changing the light schedule to 12 hours on, 12 hours off. SOG is a fairly easy technique that boosts yield and speeds up the growth cycle.

Tip #4 – Blackberry Kush Yield

Blackberry Kush’s yield is classified as ‘moderate.’You should get around 16 ounces per square meter indoors, and up to 28 ounces per plant outdoors. One of the most important tricks when growing any marijuana strain is to understand when it is the right time to harvest. Blackberry Kush is no different to most strains insofar as there is a 2-3-week harvest window.

One of the best ways to increase yield is to allow the buds to fully ripen. It isn’t unusual for buds to gain an extra 25% in size in the last fortnight before harvest. Another benefit of choosing when to harvest is that you can decide on the precise effects. If you want a buzzy high that you can enjoy during the day, harvest a little earlier. If you want a relaxing, almost sedative experience, harvest a bit later.

Tip #5 – Feeding Blackberry Kush

Blackberry Kush needs heavy magnesium feeding throughout its growth cycle. You also need to keep nitrogen intake high during the vegetative stage to help boost node development. Magnesium deficiency can significantly reduce the growth of any marijuana strain, and especially Blackberry Kush.

One of the first signs of magnesium deficiency is slower growth at the bottom of plants. You may see yellowing leaves with a crunchy brown tip. It is a ‘mobile’ deficiency which means it spreads throughout the plant. Eventually, it reaches the shoots which become purple as leaf chlorosis speeds up.

Your crop is particularly at risk if you use an inert growing medium such as Coco Noir. If you are growing hydroponically and allow the pH of the nutrient solution to go below 5.0, a magnesium deficiency is likely. If you see this deficiency, begin by flushing your plants with 6.0 pH water. Next, prepare a feed with the right pH for the growing medium you have chosen.

Prevention is better than cure, so invest in a premium quality growing medium, and nutrients specifically for marijuana plants. Some growers swear by Epsom Salts which is another name for magnesium sulfate. As a general rule, if you use Epsom Salts, add a tablespoon for every gallon of water and apply as a foliar spray every two weeks.

Tip #6 – Should I Grow Blackberry Kush Indoors or Outdoors?

You can try to grow Blackberry Kush outdoors, but it will be a challenge. It is a plant that needs to be trimmed regularly, is sensitive to inclement weather conditions, and is prone to pest infestation. On the plus side, it provides a generous yield. Blackberry Kush grown outdoors is ready for harvest by the middle of October.

Ideally, you will choose to grow this strain indoors so you can have some semblance of control over the growing conditions.

Tip #7 – Blackberry Kush Flowering Time

It is a strain much-loved by growers because it is ready for harvesting indoors relatively quickly. Blackberry Kush’s flowering time is 7-8 weeks. Growers need to keep a close watch on the plant during the vegetative stage as it is prone to pre-flowering; an action that slows down growth and overall yield.

In case you didn’t know, pre-flowering occurs when a marijuana plant in the vegetative stage starts producing clusters of hairs or pistils as they typically do toward harvest time. It is an issue seen with fast-finishing indica strains if they get stressed. Once it reaches the flowering stage, Blackberry Kush doesn’t stretch that much which makes it an excellent strain for the Sea of Green (SOG) growing method as mentioned in #3.

Overall, the flowers of this strain have a medium leaf-to-calyx ratio. As a result, you should find it relatively easy to trim the buds when it is time to harvest. Please make sure that you keep all of the trim that is covered in crystals; it makes outstanding hash!

Tip #8 – What is the Best Climate for Growing Blackberry Kush?

Blackberry Kush thrives in a mild to warm climate with a daytime temperature of between 68- and 80-degrees Fahrenheit. Remember, if you try to grow it outdoors in cool temperatures, there is a real chance that the crop will fail.

Blackberry Kush also prefers low humidity. During the vegetative stage, keep the relative humidity (RH) at 55-60%. By the time the flowers are in the blooming stage, the RH should be reduced to 40%, and can be as low as 30% by harvest time.

When RH is too high, the plants draw water from the soil at a slower rate than normal because transpiration is slowed down by the lower than usual water gradient between your plants and the atmosphere. As a result, your Blackberry Kush plants will take in fewer nutrients which leads to a deficiency. The crop’s calcium intake is most likely to be affected by a high RH.

However, it is a balancing act. If you allow the RH to get too low, your plants will draw water from the soil too rapidly; and they can’t draw water at a rate equal to what is lost via their stomatal openings. When this happens, a plant closes its stomata, an act that hinders photosynthesis. It protects the plant but leads to stress, slow growth, and reduced yield.