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

When trying to grow your favorite marijuana strain, it is crucial to understand the unique challenges you may face. You can’t grow one strain in precisely the same way as another and expect identical results.

Purple Kush is a pure indica strain known for providing nearly instant relaxation. Its THC levels can reach 27%, and it is a genetic cross between Purple Afghani and Hindu Kush. If you need to destress and enjoy an intense body buzz, you should definitely check out this growing guide for Purple Kush.

Tip #1 for Growing Purple Kush – You Can ‘Turn’ Your Weed Purple

Many growers believe that depriving weed of oxygen and carbon dioxide is enough to increase the chance of getting purple buds. However, this is NOT true, nor is the practice of boosting nitrogen intake.

In reality, you must choose a strain that is high in anthocyanin. It is the same pigment that gives blueberries and eggplants their distinct colors. Some other strains (aside from Purple Kush) that are high in anthocyanin include:

As chlorophyll’s stronger pigments hide anthocyanin, you need to create the right temperature for the compound to be expressed. For instance, during the fall, chlorophyll starts to decompose, allowing light reflected from the anthocyanin to become visible. In certain strains, it results in gold, blue, or yellow pigments emerging.

During the flowering stage, make sure you reduce the temperature during the night cycle. Ideally, it will drop below 50 degrees Fahrenheit at times. Exposing your weed to such low temperatures for too long can harm it, so monitor conditions carefully.

If you get it right, the bud turns purple approximately two weeks before harvest. (Though please note that purple buds aren’t necessarily more potent than green buds of the same strain.)

Tip #2 for Growing Purple Kush – You Can Grow Indoors or Outdoors

With a flowering time of 7-8 weeks indoors, Purple Kush doesn’t take long to provide you with delicious and relaxing weed. The plant is a typical indica. It grows short and bushy and is seldom taller than three feet, making it ideal for indoor growing. It provides you with approximately 14 ounces of bud per square meter planted.

Purple Kush behaves like a typical indica plant: short and stout. It grows in about 7-8 weeks.

It is best to grow Purple Kush in soil. However, a hydroponics system works very well as long as you keep humidity low. You can also activate the anthocyanins through exposure to temperatures of around 50 degrees, as we mentioned above. Remember, long-term exposure to cold hurts your yield, so you should only do this close to harvest time.

When growing outdoors, make sure that exposure to rain and humidity is limited. Purple Kush is ready for harvest earlier than most strains (mid-September) and provides eight ounces per plant.

Tip #3 for Growing Purple Kush – Prune Your Purple Kush for Maximum Yield

Pruning a marijuana plant is usually a good idea, but it is especially

beneficial when growing Purple Kush. After pruning, your plants will be short and have robust stems, and you could end up with an increased yield.

The idea behind pruning is to expose the smaller buds to light, or else the chemical auxin limits their development. When you trim the big central bud, you end up with several large buds instead of one gigantic one and many tiny buds.

Make sure you only prune Purple Kush during the vegetative stage because the plants need time to recover. Don’t force your plants into flowering for a minimum of three days after pruning. It is also essential to reduce fertilizer usage during this timeframe to aid recovery.


As Purple Kush is such a small and bushy plant, it is ideal for the Screen of Green method when grown indoors. If you go down the SCROG route, place a screen 0.5m above your Purple Kush plants. Take the top off each one once it is 0.1m through the screen and wait until the new tops grow 0.1m through. Next, bend them and connect the tops to the screen.

Begin pruning when the first shoots have grown through the screen. After a few days, switch the light cycle and force your plants into the flowering stage. Experts say that using the SCROG method in conjunction with proper pruning should provide a gram of weed per watt of light. In other words, a single 400-watt HPS bulb could yield 400 grams (over 16 ounces of cannabis). However, expect Purple Kush’s yield to be significantly lower.

Tip #4 for Growing Purple Kush – If You Want to Use a Hydroponics System

A Purple Kush plant can thrive if you use a hydroponics system for indoor growing. However, you must ensure that the grow room’s humidity levels are in check.

In case you didn’t know, hydroponics involves growing marijuana in an inert medium such as Rockwool. Soil contains bacteria, fungi, and nutrients, whereas inert growing mediums do not. As a result, you need to add the nutrients, but there is no danger of diseases or pests coming from Rockwool.

Purple Kush performs exceptionally well when you use a hydroponics system. It is capable of greater nutrient intake than sativas, without the risk of overloading. If you are a new grower with a relatively small number of plants, the Wick System is a good option. It is very basic and straightforward to use. Connect your pots with a thick wick dipped into the reservoir. The reservoir is the vessel that holds the water. Then, all you have to do is monitor your plants now and again.

Purple Kush is a great candidate for hydroponics, as it’s capable of massive nutrient intake without the risk of overloading.

Ideally, you will choose a reservoir large enough to hold at least one week’s worth of nutrients. It should also have a lid, or else you risk losing moisture to evaporation. Keep it close to a water source and purchase at least one backup reservoir.

Another popular hydroponics method worth investigating when growing Purple Kush is Deep Water Culture (DWC). This involves suspending the roots of the plants into a highly oxygenated nutrient solution. DWC systems are easy to build and extremely effective. Every plant has an individual reservoir filled with a nutrient solution. There is also a container at the top that has an inert growing medium. The roots hang into the solution.

Tip #5 for Growing Purple Kush – Nutrients for Hydroponics Systems

Mixing your nutrient solution using a hydroponics system is relatively easy. However, it must be performed accurately, or your Purple Kush will suffer.

In theory, it is as simple as filling up your reservoir with reverse osmosis water, adding the nutrients and additives, and adjusting the pH.

Nutrient concentrations depend on the strain you’re growing. However, it’s better to underfeed than overfeed because the latter can shock the plant for weeks and cripple its development. In contrast, a Purple Kush plant can go without nutrients for several days as it absorbs existing nutrients well.


The three most important nutrients are nitrogen (N), phosphorus (P), and potassium (K). Secondary micronutrients include boron, copper, zinc, sulfur, and magnesium. You should purchase and use nitrogen-rich solutions during the vegetative stage and switch to phosphorus-rich solutions during flowering.

You can buy these nutrients in powder or solution form. Although the former is cheaper, the latter works best for small crops. Nutrients in solution form mix well with water and allow for a greater degree of error.

You will get reasonable results by following the instructions to the letter. However, experienced growers know that it is best to begin with 25-50% of the recommended dosage before slowly increasing it as necessary.

Once you reach the 50% mark, it is unlikely that your plants will show nutrient deficiencies. If you are underfeeding, your plants will exhibit a yellowish color and start drooping. If this happens, increase the dosage.

In contrast, if your plants show burnt leaf tips, they are clearly suffering from nutrient burn. If this happens, it can take weeks for your plants to recover.

Tip #6 for Growing Purple Kush – Pay Attention to Electrical Conductivity (EC) Readings & Parts Per Million (PPM) When Using Nutrients

The trouble with mixing in nutrients is that you have no idea if it is safe for your plants without accurate measurements. The Electrical Conductivity (EC) reading tells you how strong the solution is. The greater the mineral content, the higher the EC number. Ideally, the EC level will be in the 0.8 to 2.0 range. The figure should also be lower in young plants because they need fewer nutrients than a flowering plant.

Parts per million (ppm) is another method of checking nutrient content. In the marijuana industry, there is a 500 and a 700 scale. To determine ppm, multiply the EC figure by either 500 or 700, depending on the scale you use. For example, if you use the 500 scale and your nutrients’ EC reading is 1.6, you are using 800ppm.

Here is a quick guide to typical ppm densities based on a marijuana plant’s growth cycle:

Seedling100 – 250
Early vegetative stage300 – 400
Late vegetative stage450 – 700
Early booming750 – 950
Mature 1000 – 1600

If you use a hydroponics system, you can increase nutrient intake earlier in a Purple Kush plant’s life. It is not unheard of for growers to provide up to 1100 ppm of high-quality nutrients within a week of the plant establishing strong roots.

This is probably far too high and risks nutrient burn, but many experienced growers swear by it. We recommend sticking to the ranges in the table above.

Tip #7 for Growing Purple Kush – Maintain the Right pH with Hydroponics

Aside from the EC level, pH is perhaps the most important factor in water and nutrient management. pH is the measure of an aqueous solution’s acidity or alkalinity. The pH scale ranges from 0 to 14. A pH of 6.9 or lower means a solution is acidic, 7.0 is neutral, and 7.1+ is alkaline.

The pH your marijuana plant is exposed to determines its ability to absorb nutrients. If the pH is too high or too low, your plants won’t absorb nutrients efficiently. Naturally, your plant’s development, and ultimately the overall yield will suffer.

DID YOU KNOW? The pH levels your marijuana plants are exposed to determine their ability to absorb nutrients.

When you grow Purple Kush in soil, it is best to keep the pH in the 6.2 – 6.8 range. This figure drops slightly when using a hydroponics system. Soil has a natural pH buffering ability, which gives you the liberty of being less than accurate. However, when providing feeding solutions, you don’t get the same margin of error with hydroponics.

Make sure you invest in a high-quality pH meter because you will have to measure it quite often. Although the pH range is 5.2 – 6.2 for hydroponics, 5.8 is classified as ideal. If the pH is too high or low, invest in pH UP or pH DOWN solutions as necessary and make the requisite adjustments.

There is also a difference in pH between hard and soft water. Hard water tends to have an elevated pH level and contains high levels of bicarbonates. It takes more acid to lower the pH of hard water than its soft equivalent. Use a reverse osmosis (RO) system to filter your water and eliminate any potential difficulties caused by hard water.

Tip #8 for Growing Purple Kush – Temperature & Humidity Levels

Purple Kush is a difficult strain to cultivate. As it is a pure indica, it grows low to the ground and is extremely bushy. As a result, it is tough to grow outdoors properly. Purple Kush is particularly vulnerable to rain exposure and high humidity. Although this strain is resistant to pests and mold, it is susceptible to disease if you allow it to get wet. On the plus side, pests don’t like Purple Kush because of its bitter taste.

There are different schools of thought regarding Purple Kush’s ideal growing temperature. It is widely believed that it prefers relatively cool temperatures of 65 – 75 degrees Fahrenheit, but some growers claim that their Kush flourishes between 77 and 85 degrees. We recommend keeping the temperature below 80 degrees for the most part and not dropping by more than 10 degrees at night.

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As for humidity, it is best to keep it at around 50% during the vegetative stage. Remember, the relative humidity (RH) in a plant cell is close to 100%. Therefore, when the RH in the air is lower, a more significant amount of water is removed from the leaves. Generally, growers like to keep the humidity level high to reduce the number of times they have to water the plant.

With Purple Kush, you have to keep it lower than normal. Once you get to the flowering stage, you can reduce the humidity levels by a few percent each week. By the time you are close to harvest, it is normal to have the humidity level down at 40%, or even less on occasion.

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