A Guide to Hydroponic Nutrients

To a newbie, it may seem that hydroponics is all about the fancy hardware and tech wizardry. One of the biggest mistakes that beginners make is to invest too much time and money in their systems, and not enough in their nutrients.

The key to a thriving hydroponic garden lies in the nutrients. With traditional gardening, the soil supplies a certain level of nourishment to plants. However, with hydroponics, the growing medium doesn’t provide any sustenance, meaning minerals must be added manually to ensure the crops survival. This is done by adding a well-adjusted balance of nutrients to the water in your system. The nutrients are then delivered directly to the roots (and sometimes leaves) of the plants.

In an ideal lazy world, you would simply be able to add the fertilizer to your water and let the hydroponic system do the rest of the graft. Unfortunately, if you really want your crops to reach their full growing potential, then a little more elbow grease is necessary. To guarantee a bountiful harvest, you must first look at the minerals that plants need to survive.

Lucky Number 16

There are 16 nutrients that plants require to thrive. They are-

Carbon, Hydrogen and Oxygen

Carbon, hydrogen and oxygen are absorbed into the roots from water and air. This is why oxygenating the water supply in your system is so beneficial. Just do it!

Nitrogen, Phosphorous and Potassium (N.P.K)

These minerals are normally derived from the main fertilizer.

Nitrogen deficiency results in pale yellowish green leaves. Potassium deficiency causes yellowed leaves speckled with black spots.

Calcium Nitrate (CaNO3)

Calcium nitrate is another important fertilizer that will boost your crop.

Lack of calcium causes young leaves to become misshapen with spots of dead tissue.

Magnesium and Sulfur (MgSO4)

Magnesium and sulfur can be obtained from magnesium sulfate.

Magnesium deficiency is common in tomato plants. Signs include yellowing between the veins on older leaves.

The remaining 7 nutrients are rarely deficient. They are:

  • Boron
  • Zinc
  • Copper
  • Iron
  • Chlorine
  • Manganese
  • Molbydate

Which Fertilizer Is Best?

With such a wide array of necessary nutrients, getting the mix right is crucial. Regular potting mix won’t suffice, as it is designed for traditionally planted vegetation that already has a ready supply of nutrients available in the soil.

There are 2 types of hydroponic fertilizers– liquid and dry. Liquid fertilizers are a one-part solution that is diluted in the system water and circulated. Liquid fertilizers are popular among hobbyist growers as they are quick and convenient. However, if you are serious about your hydroponic harvest, then you might want to consider a dry or powder fertilizer.

Dry fertilizer is available as one-part mixes, multi-part mixes and many part mixes. One-part mix is an all-in-one powder that is simply added to the water at the rate instructed on the packaging, making it convenient and hassle free. Happy days! However, nutrients have a tendency to solidify when mixed together in high concentrations so one-part mixes aren’t the best option for making stock solutions.

Multi-part mixes are a superior choice for home growers as they are relatively easy to mix and as the compounds are kept separately, they do not have problems with solidification.

Many-part mixes are formed with up to 11 different minerals which all need to be stored and mixed separately. Because of this, they are only practical for larger commercial operations.

3-part fertilizers are the most frequently used nutrient mixes for hydroponics systems. They use a blend of N.P.K, CaNO3 and MgSO4.

Powdered mixes are more cost effective than liquid mixes as they are cheaper to ship. The concentration and balance of your mix can also be easily adjusted depending on the needs of your plants.

Check Your Levels!

Once you have a good balance of nutrients, the next hurdle is making sure that you have the proper concentration of nutrients in your solution. EC (electrical conductivity) is the most commonly used unit to determine solution concentration.

The theory behind it is a little complex. Basically, when a mineral compound is added to water, it splits into two charged particles, a positively charged cation and a negatively charged anion. The strength of the solution is directly proportional to the strength of the charge. In other words, the higher the solution concentration, the higher the EC is.

Bringing back awful school memories of double physics class on a Monday morning? Thankfully, there’s a handy little gadget called an EC meter that will do all the science-y stuff for you, demystifying the whole complicated process. Phew!

Unsurprisingly, different plants prefer different EC ranges, so running the correct EC for your crop is imperative. Grow your fruit and veg at an imprecise EC level and you’ll end up with issues like stunted growth, disfigurement, lack of taste, shortened shelf life etc. Measure and adjust your EC level regularly to guarantee maximum growth.

What About PH?

The PH of your nutrient solution is another critical factor to consider. Whereas EC measures the concentration of nutrients in the water, PH determines the usability of those nutrients. Not much good having the ideal EC if your roots can’t uptake the fertilizer because the PH is incorrect, is it?

PH can be measured simply by using a PH pen. Ideally, it should be checked twice a day. If the levels are too high or low, they can be altered using a PH adjustor.

If you love a bit of high-tech wizardry, you can automate the process by using an auto-dose system. This is a computer equipped with sensors and pumps that continuously monitors the PH of your system and adjusts it accordingly.

When it comes to hydroponics, it’s easy to get lost in the hardware of your system. However, to guarantee that your plants reach their full growing potential, nutrient balance and concentration are the two dynamics that will make or break your crop. Watch for any signs of deficiency and act fast when you spot something amiss. As the saying goes, prevention is the best cure!


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