Raising a plant with hydroponics is different in many ways from growing in a soil garden. One thing to consider is the support the plant is receiving. Unlike a plant growing in soil, plants in hydro mediums might be vulnerable to tipping or breaking. Trellising your garden will help to prevent this from happening and will also allow you to train your plants to grow in specific directions.
Many companies sell hydroponic nutrient solutions that are specifically designed for certain stages of growth. Nitrogen-rich nutrient solutions will be used in the vegetative stage while phosphorus-rich nutrients become more necessary in the flowering phase.
Another thing to consider is pruning. With hydroponics, your plants can grow extremely fast. This means you need to be diligent about pruning. Removing all the bottom foliage and topping your plant before switching to its flowering cycle will allow your top colas (the large, topmost buds) to receive all the energy they need.
Whether you have grown cannabis before or have no experience growing cannabis whatsoever, hydroponics can be a great way to produce cannabis in any size space. At first it can be confusing and slightly overwhelming, but by learning the basics you will come to understand it’s not as difficult as you imagined.
Explore Nutrients for Your Hydroponic Cannabis
Once you have gathered your materials you can begin to construct your hydroponic setup.
The common nickname for cannabis—“weed” —comes from its ability to grow almost anywhere, under varying conditions and different climates. “Hydroponic cannabis” simply refers to plants grown using a nutrient-water solution and an inert growing medium rather than nutrient-rich soil. This method could be something as basic as hand-watering pots of inert medium with a nutrient solution. As discussed in the first part of this series, sophisticated systems with multiple pumps, timers, and reservoirs can take some of the daily labor out of growing, but they require more maintenance and setup time as well as a greater initial investment.
The lower the ppm, the less nutrient-dense a solution is. As a general rule, aim for the following densities based on your plant’s age:
Browse Hydroponic Growing Supplies
Another common measurement used is ppm (parts per million) which is another way of looking at how nutrient-dense your solution is. There are two different scales for ppm used in the cannabis industry: the 500 and the 700 scale. The most efficient way to determine ppm is to take an EC reading, multiply it by either 500 or 700 depending on the scale you are using. An EC reading of 2.0 would equal either 1,000 ppm (500 scale) or 1,400 ppm (700 scale). Many readers used to measure EC or ppm will do this conversion for you.
I n the previous post, we gave an overview of hydroponic gardening including its origins, the various systems and techniques, and medium options for a hydroponic grow. In this next article, we will focus how to use hydroponic systems specifically for growing cannabis.
Which Nutrients to Use:
You can use any nutrients you prefer as long as they’re formulated for hydroponic systems (as opposed to soil) and are also specifically made for plants that have a vegetative and flowering stage (if you see tomatoes on the label, you’re golden!).
These powerful lights are pretty much seen as the golden standard for indoor growing lights. They will definitely give your plants what they need to grow huge, but they also make a lot of heat and can dramatically raise your energy bill depending on where you live.
Replenishing Reservoir Water:
75 degrees (+/- 5 degrees) is optimal. With this type of growing system, high temperature can be a huge problem (especially in warmer areas). Bacteria loves nutrients and warm water, so your reservoir will be the perfect place for them to reproduce if you can’t keep them out. There are two main ways to go about fighting bacteria/algae.
Your cannabis will need room to spread out a bit, so you’ll want to keep the total number of plants to 3 or less in a single system. The more plants that go into a single reservoir, the smaller each plant will need to be. I generally grow only 1 or 2 cannabis plants in a top-fed DWC system at a time.
The Importance of Managing pH:
Seedlings and Clones:
Add 1/4 of the recommended nutrients after 1 week (during your first reservoir change), then work your way up to 1/2 over the next few weeks. Watch the tips of your leaves and back off if they start to appear yellow, brown or crispy. Giving plants too much nutrients is a common mistake and if you do notice signs of nutrient burn, you will want to drain their water and replace it with water that contains lower amounts of nutrients. However, if they seem pale and the pH is in the correct range, they might need more nutrients instead.