Ask GroMomma – January 2020

by Kathy  Goff

This month we will continue to focus on indoor growing. Before starting your cannabis grow, you must decide what kind of an indoor growing system you want to use. Will you grow your plants in water, soil or a combo?  

One type of hydroponic growing is growing a plant’s roots in a tub of water. Roots grown in water do not need to expend energy to search for the nutrients the plant needs; nutrients are easily accessible by the roots. Since the plant is spending less energy finding what it needs to grow, it channels that energy to plant growth.

A bubbler bucket reservoir is a simple system that suspends the plant’s roots in a highly oxygenated nutrient solution. Plants have an unlimited supply of oxygen because of the air-stone in the tub/reservoir. The roots are submerged in the oxygenated nutrient-water solution in the bucket which is replenished regularly.

The most important growing tip is to check your cannabis plants daily.  As with many processes, it is easiest to fix a problem in the beginning stages! If something is wrong with your plant in a hydroponic system, your first step is to change out the reservoir. It is common for root rot to occur when roots are consistently in water and poorly oxygenated. It is imperative to establish a preventative routine of changing out the reservoir every seven days. 

Keeping air and water temperatures under control are also very important. Air temperature should be 75-85°F when the lights are on, and will drop by 10 degrees when the lights are off. Water temperature should remain at a constant temperature at all times. 

Too many plants in one reservoir can lead to problems, such as white powdery mildew. Don’t cramp your plants, instead, grow one plant per reservoir.  This will allow the roots to spread out and give the leaves and buds more space to grow.

CoCo Coir is another great growing method, especially for beginners. It provides the ease of soil gardening, with the rapid growth of hydroponics, by using fibrous coconut husks instead of a potting mix. Compared to soil growing, the lighter texture of CoCo Coir absorbs moisture much easier, and allows plants to take up more nutrients and retain oxygen more efficiently. It also dries out more quickly than soil, so be aware.

Good quality coco coir is important for successful root development. It is recommended that beginner growers use a three-to-one coco to perlite mixture because it requires less frequent watering.  Perlite is a mined mineral that creates small spaces of air in the coco coir to prevent overwatering. It also provides more oxygen to the roots. Cannabis roots love oxygen and perlite lets them get it while the coco coir makes sure the roots always stay wet.

Finally, growing cannabis in soil is a system that requires any kind of good quality potting soil. It is also best to avoid any soil with artificial extended release fertilizer or other chemicals. I use Fox Farm Ocean Forest potting soil. It contains lots of nutrients, so you won’t need to add any additional nutrients for the first couple of weeks. If you keep re-potting the cannabis plant, you may never have to add any nutrients.

When it comes to selecting pots to grow cannabis, I recommend the fabric variety with handles. They are a great option for growing cannabis. If you want to use pots that you already have on hand, that works fine, too. Just be sure your pots have some holes in the bottom for drainage. If you use a regular bucket, for example, make sure to drill a few holes in the bottom.

The size of pot used to grow cannabis is determined by the stage of growth.  You will want a small pot (1 gallon or less) for seedlings, but you can also use a plastic solo cup.  When the seedlings have grown and are ready, transplant the plants into larger bags/pots. The larger the pot/bag, the larger the plant. An easy way to tell that they are ready for a bigger pot is when the roots start coming out of the drainage holes in the bottom of the pot. 

I think these three growing methods are the simplest and easiest to use when beginning to grow cannabis.  Of course, it’s a personal decision with no clear cut path to success. It is pretty much a trial and error process until you learn a method that works for you.  There is no shortage of advice from the Internet or you can consult your local grow supply store. Remember, cannabis is a positive energy force and growing it with joy will increase its yield. Send your questions to 


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