Soil growers – unless you’re growing with composted super soil, you will need to get cannabis nutrients made for soil to make sure your plants produce at their best. Even if you started with an amended soil like FFOF, you will still need to start adding nutrients once you reach the flowering/budding stage as cannabis plants are heavy feeders and your plants will have already used up most of the nutrients in the soil by the time budding begins.
Soilless & Hydroponic growers – If you are growing in any medium besides soil, like a soilless mix or directly in water, you will want to get cannabis nutrients specifically made for hydroponics. Some nutrients are even more specific; for example, Canna Coco is formulated to work best for growing weed in Coco Coir.
One nutrient system to rule them all…
Looking for a suggestion? One of the simplest (yet inexpensive) nutrient systems that works extremely well for beginning cannabis growers is Dyna-Gro.
Dyna-Gro can be used at half-strength in soil, water, coco coir, or any growing medium and works amazingly well for growing cannabis. It does not build up salt in your growing medium like many other inexpensive fertilizers, and it will never clog your hydroponic system.
Just use the “Grow” bottle during the Vegetative stage and the “Bloom” bottle during the Flowering stage. You can actually follow the instructions on the bottle. It’s super simple.
Like all nutrient systems, avoid starting at full strength or it can burn your plants! Only raise the dosage if you notice that your lower leaves are turning yellow and falling off (except in the last 2-4 weeks before harvest, when yellowing lower leaves is a natural part of the maturation process)
Is my tap water “good enough” for growing cannabis?
Before I address pH, let’s talk about the “hardness” of your water…
The “hardness” of water describes how much extra “stuff” (like minerals and/or impurities) is contained in your regular tap water. You can contact your local water supplier for more information (ask for a “municipal water report”), or you can test the PPM of your water at home. Generally, as long as your water has less than 200-300 PPM (parts per millions) of extra stuff, it should be okay to use it for growing. If you are worried about the quality of your tap water, you can choose to use purified or Reverse Osmosis (RO) water, but you may then need to add extra Cal-Mag and possibly a few other supplements to help make up for the random minerals and nutrients that are normally found in tap water. I’ve personally always grown with straight tap water (in a big city in California with a natural PPM around 370, which is pretty high), and I’ve never had a problem. However, some places have very hard water, or tap water with unacceptable impurities, and growers in these areas will likely need to use purified water to get the best results.
Nutrients, continued: The Importance of Root pH
It’s important to maintain the pH of your root environment to prevent nutrient problems.
The easiest way to do that is to test the pH of your water before you water your plants or add water to your reservoir.
There are certain types of grows (such as when growing cannabis in organic composted super soil) where you don’t need to test your pH unless you run into problems. This is because with a properly composted super soil, you actually have a microbial colony living in the soil that will take care of the pH and hand-deliver the nutrients to the roots of your plants for you. However, this is a rare exception to the pH testing rule, and almost all growers need to regularly test and maintain pH for a successful grow. If you’re not growing in super soil that you have amended and composted (or purchased) yourself, testing and maintaining pH is a MUST.
Some growers will always get lucky and successfully grow weed without testing the pH of their water, but most people who don’t test for pH will start seeing signs of nutrient deficiencies and other nutrient problems.
If the pH at the plant roots is too high or too low, your plants won’t be able to absorb nutrients properly.
Even if plants do fine in the vegetative stage, cannabis plants tend to be more picky and prone to problems in the flowering/budding stage. Many growers have written in to tell me they got all the way to the flowering stage without testing pH, then were surprised that they start running into nutrient problems as soon as the plants start budding. In order to make sure this doesn’t happen to you, it’s important to get in the habit of testing pH right from the beginning!
Even if the right amounts of nutrients are present, your cannabis plants simply cannot absorb them if the pH isn’t in the correct range.
It’s actually really easy, quick, and cheap to learn how to check and adjust the pH of your water, and there are “pH test kits” specifically made for this purpose.
After you get the hang of it, checking and adjusting the pH and will take you less than 3 minutes each time you water your plants. And your results (monster yields with huge buds and healthy plants) will speak for themselves.
Soil: Maintain 6.0 – 7.0 pH
Hydroponics: Maintain 5.5 – 6.5 pH
Getting the pH exactly right isn’t nearly as important as checking regularly and making sure it stays within these ranges.More about:grow light led