Hydroponic systems require specific hydroponic nutrients because of the soilless growing conditions. Hydroponically grown plants sit in mediums such as hydrocorn, puffed rock, expanded clay pellets, rockwool, coco coir, Growstone, grow rocks, or perlite. With deep water culture (DWC), no medium is used at all around the plant’s roots. Without soil, the plant has no way to absorb nutrients; instead, it must rely on hydroponic nutrients to fulfill its nutritional and mineral requirements.
Hydroponically grown plants require daily doses of hydroponic nutrient solutions to grow. The nutrient-rich liquid solution is delivered to the plant’s root system via an ebb-and-flow tray. Several times a day the hydroponic nutrients are flooded into the tray around the plant’s roots and then drained away into a reservoir for later re-use. Once the liquid drains away from the plant’s roots, the plant is able to absorb oxygen.
Hydroponic nutrients are often sold in multi-part bottles, one for grow and one for bloom. This is because plants require different amounts of different nutrients throughout their growth cycles. In this way, a grower is able to dial in their crop’s nutritional needs in order to maximize yields.
Choosing your fertilizer
Basically, there are two deciding factors: wet vs. dry, and what crops you’re going to be fertilizing. Don’t forget that different crops have different nutrient demands!
If you’re a commercial grower, there’s a 99% chance that a dry fertilizer will be best for you.
Commercial nutrient mixes also come in dozens of different ratios. I’m talking about nitrogen, phosphorous, and potassium—or NPK—which different plants require in different amounts.
If you’re growing greens, you’ll want to use something different than if you’re growing, say, tomatoes. This will maximize plant health and help you get the best possible production out of your system.
For hydroponics, you’ll want to have these three nutrient mixes to regularly fertilize your system:
- N-P-K mix
- Calcium nitrate
- Epsom salt (magnesium sulfate)
Your crops will be claiming oxygen, hydrogen, and carbon from the water and air around them. For the most part, you don’t need to worry about those three.
The rest of the primary nutrients are nitrogen, phosphorous, and potassium. Those will be provided in the NPK fertilizer you use.
The secondary nutrients are calcium, magnesium, and sulfur.
If you can’t tell by the name magnesium sulfate, magnesium and sulfur are supplemented in this compound—Epsom salt.
Obtaining the right balance is crucial for growth and achieving a good harvest. The label on hydroponic nutrients is written as N-P-K and can read 10-5-5 for example. This indicates that the solution has 10% Nitrogen, 5% Phosphorous, and 5% Potassium.
Each nutrient plays a different role. Nitrogen is important for the growth of a plant, phosphorous plays a crucial role as it encourages the growth of the roots and flowers, and potassium is responsible for the growth of roots and for photosynthesis.
Check the label on the nutrient mix you are using and follow the instructions provided there. The amount of Epsom salt you add will also be formulated on the label of your nutrient mix.
Check your nutrient levels daily. You will likely need to top off your system every few days, and add nutrients to compensate for both plant use and the dilution of the top off.
Understanding and using hydroponic nutrients correctly can make all the difference in the type of yield one receives. The more care and attention one provides to these plants, the better the harvest. It’s as simple as that. That’s why it is crucial to understand the basics of hydroponic nutrients.
After following the basic principles outlined above, not only will the harvest be better, the approach to hydroponics will be more systematic and less trial-and-error.