Hydroponic Cilantro Nutrients: What to Mix and How

Cilantro in a Kratky setup gets everything it needs from the water, so the nutrient solution matters. This post covers hydroponic cilantro nutrients in plain terms: which kind to buy, how to mix it, and how to check it. It builds on step two of the step-by-step Kratky method guide for cilantro, "Add Nutrients".

Choose a hydroponic nutrient

Buy a nutrient made for hydroponics. Unlike soil, water holds no minerals of its own, so a hydroponic nutrient supplies the major nutrients plus the trace elements the plant needs. Products for leafy greens and herbs suit cilantro. Some come as one bottle, and others as two or three parts that you add separately.

Start with clean water

Use clean water. If your tap water is heavily treated or very hard, filtered water can give more consistent results. Fill the container first, then add the nutrient, so you can mix it evenly.

Mix it as the label says

Follow the maker's ratios. The guide says to mix the nutrients into the water, "following the recommended ratios for cilantro growth," and to stir gently so they blend. If the label gives a range, many growers start at the lower end for young plants and raise it for mature ones. A more concentrated solution is not better, and too strong a mix can harm the roots.

Check the pH

pH measures how acidic or alkaline the solution is, and it controls how well the roots take up nutrients. The guide recommends 6.0 to 6.8 for cilantro. A pH meter is on its list of materials. Test after you mix the solution, because adding nutrients changes the pH. Hydroponic shops sell "pH up" and "pH down" products to adjust it in small steps.

Optional: a TDS or EC meter

A TDS or EC meter reads the strength of the solution. It is not required for a small Kratky setup, but it helps if you want to confirm that you mixed the strength the label intended.

Topping up

The guide says to check the water level regularly and top up as necessary so the roots stay in the solution. When you add water, check the pH again. For how the air gap and the roots work together, see Kratky cilantro container: what size and type to use.

Signs that something is off

• Pale, slow growth can point to weak nutrients, or too little light.
• Brown or slimy roots call for fresh solution and a clean container.
• Algae means light is reaching the solution; cover the container.

When the plants are growing well, harvest often. How to harvest cilantro for bushier plants has the details.

Mix before you plant

Make the solution first and let it mix fully before the seeds or seedlings go in. Check the pH, adjust it if needed, and only then add the plants. Mixing in the right order avoids stressing young roots with a solution that is still settling.

Common questions