How to Choose the Right Nutrient Solution for Your System

The key macronutrients every crop needs: Nitrogen (N), Phosphorus (P), and Potassium (K) — commonly called NPK. Add to that secondary elements like calcium, magnesium, and sulfur.

How to measure concentration: use an EC (electrical conductivity) meter. Ideal readings vary by crop: lettuce between 1.2 and 2.0 mS/cm, tomatoes between 2.5 and 4.0 mS/cm.

How to measure pH: the ideal range is 5.5 to 6.5 for most crops. Outside this range nutrients become unavailable to the plant even if they are present in the solution.

When to change the solution: every one to two weeks in DWC systems — or when EC rises more than 20% above the recommended ceiling.

Practical tip: buy a pre-mixed two-part solution (A+B) to start rather than blending individual elements — simpler and safer for beginners.