Nutrient Basics

Hydroponic plants get everything they need from the water, so getting your nutrients right is the most important part of tower growing. The good news: it is simpler than it sounds.

The Two Numbers That Matter

EC (Electrical Conductivity) measures how much nutrient is dissolved in your water. Higher EC means more food for the plants. For lettuce and herbs, you want an EC between 1.0 and 2.0 mS/cm. Seedlings do best at the lower end (1.0–1.2); mature plants can handle 1.5–2.0.

pH measures how acidic or alkaline your water is. Plants can only absorb nutrients within a certain pH range. For tower systems, keep your pH between 5.5 and 6.5. If it drifts higher, nutrients get locked out even though they are in the water. Check pH at least weekly — it tends to drift up over time as plants consume nutrients.

Mixing Nutrients

We recommend a three-part system: a calcium-nitrate base (Part A), a magnesium-sulfate blend (Part B), and a micronutrient supplement. Never mix concentrates together before diluting — always add Part A to the full reservoir of water, stir, then add Part B. Mixing concentrates directly can cause nutrients to bind together and become unavailable to the plants.

Start with the manufacturer's recommended dose, measure your EC, and adjust from there. Add small amounts at a time — it is easier to add more than to dilute an overly strong solution.

pH Adjustment

Use a pH down solution (phosphoric acid) to lower pH and a pH up solution (potassium hydroxide) to raise it. A little goes a long way — add a few drops at a time, circulate for a few minutes, then re-test. Kansas tap water tends to run alkaline (pH 7.5–8.5), so you will almost always be adjusting down.

Reservoir Changes

Do a full reservoir change every 2–3 weeks. Drain the old solution, rinse the reservoir, refill with fresh water, and re-mix your nutrients. This prevents salt buildup and nutrient imbalances that develop as plants selectively absorb different elements at different rates.