Most hydroponic crops grow well in a slightly acidic range, often cited as about 5.5 to 6.5. The right number depends on the plant, so check the requirements for the crop you are growing.
Why It Matters
pH controls how well plants can take up each nutrient. A solution outside the range can lock out nutrients even when they are present, so plants may yellow even when the fertilizer is correct.
How to Adjust It
- Measure with a meter or test kit.
- Adjust with pH up or pH down, a little at a time.
- Mix, wait, then measure again. Solutions can take a moment to settle.
Related guide: pH and EC.
