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Happy seedlings improve cannabis quality

I had the privilege of making a presentation at the Cannabis Tech Conference in January in Abbotsford, B.C., on the topic of cannabis quality and nutrient management. I had a chance to meet a large number of growers, scientists and specialists.

April 29, 2019  By Mohyuddin Mirza

One must understand the business of the cannabis plant right from the beginning to maintain good quality.

How to produce quality cannabis product consistently and repeatedly was the subject of discussion with these participants. In my opinion, we should grow seedlings that are happier and the criterion is that it makes you happy.

Where to begin
There is no one starting point for quality. There are multiple touch points growers should understand. I am finding that sometimes quality control specialists don’t understand that good quality starts much earlier than the end product. One must understand the business of the cannabis plant right from the beginning to maintain good quality.

I always tell growers that the key business of the plant is not making money for you but to fix light energy in a useable form so that it can produce the chemical compounds you need – and that is the photosynthesis.

So the starting point is that the plants are able to trap light effectively and the leaves are the major parts of the plant that need that light.


In indoor situations the only light is top light. Once the plants start growing upward, the lower leaves don’t get enough light and start turning yellow. That is not a good way to maintain optimum photosynthesis.

Good optimum light is essential to have good quality plants, and the most commonly asked question is, ‘How much light and what spectrum?’ I will write more on this subject, light for cannabis, in another issue. Let me go back to the starting points for good quality.

The choice of good quality seeds and clones is key. The picture shown here is of a well-rooted clone, well-branched, and good root-to-shoot ratios. They appear to be free of diseases and insects. When you look at such seedlings, it gives you a feeling of pleasure and happiness. This seedling was exposed to optimum light from all sides, top, bottom and sides.

This seedling was also provided optimum nutrients to establish good quality. A proper pH and EC was maintained. That is why we have those standard operating procedures. Growers should have that knowledge of optimum nutrient management, use of pH and EC meters, above all.

Notice how beautiful the root hair are? This means that there is good oxygen dynamics in the root zone and these roots can absorb all the nutrients properly.

White colour is another indication of good quality, as well as good branching, properly elongated and green leaves. All indications are that this seedling is of good quality and ready to make a good quality “adult” plant. The foundation of quality is the good seedlings.

Looking after the early “childhood” phase for cannabis is important for quality later on. It is very important to let the plant establish itself before we prepare for the buds. Let the plant build its proper structure and symmetry for which it is designed. Too tight a spacing, where plants are growing into each other, is a sure recipe for lower quality plants and buds.

Build a plant with 4 to 6 side branches, not 10 to 12 side shoots. For quality, maximize light penetration down to the lower leaves. Once they start turning yellow, it means all the energy the plant puts into those leaves are wasted.

Everything the cannabis plant does is based on costs and benefits. A good example: if the plant itself has to transpire lots of water to keep itself cool because the cooling system of the grow operation cannot keep up with the heat generated by the light, then the bud quality is going to suffer because energy is used differently.

Water and watering practices must be understood in the context of ultimate quality. Cannabis plants, like other plants, are designed to transport water from roots to top. Nutrients are retained in the cells and water is lost through stomata. Transport of this water requires quite a bit of energy and we must balance this with energy uses.

Nutrient management also has a very important role in determining quality. As the plants grow, optimum nutrients are to be supplied in right amounts and at the proper time. Too much nitrogen will result in a very vegetative plant and will result in poor quality buds. This will also cause the plants to be more susceptible to diseases like grey mold and powdery mildew.

Climate control, which means proper temperature – day and night, 24 hours average, day to night ramping and night to day ramping, and relative humidity – all have an important role in determining quality.

Proper drying and post harvest handling also affects bud characteristics and thus, quality.

The point is made that quality has to start right at the planning stage, and all aspects of management will determine the quality of the plants and the quality of the end product. This translates to your reputation in the marketplace.

Dr. Mohyuddin Mirza is an industry consultant with more than 37 years of experience in crop development, production and marketing. He specializes in the technical aspects of hydroponics and systems for plant production.

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