Cannabis pH Guide: Soil vs Coco vs Hydro Targets
pH does not feed the plant — it decides which nutrients the roots can actually absorb. Out-of-range pH produces deficiency symptoms in a plant surrounded by plenty of food.
Targets by medium
Soil: 6.2-6.8. Coco and soilless: 5.8-6.2. Hydroponics and DWC: 5.5-6.0. Living soil with a healthy microbial population is the most forgiving and largely self-buffers.
Measure last, not first
Mix all nutrients and additives into your water first, stir, then measure and adjust pH. Nutrients shift pH significantly, so adjusting before you mix wastes your effort.
Drift on purpose
Different nutrients are absorbed best at slightly different pH values. Many growers alternate between the low and high end of their range across waterings so the plant gets access to the full menu.
Calibrate the meter
A drifting pH pen is worse than no pen. Calibrate monthly with 4.0 and 7.0 solution and store the probe wet in storage solution, never in plain water.
Frequently asked questions
- Can I use pH strips?
- They are better than nothing for soil, but the resolution is too coarse for coco and hydro. A digital pen pays for itself quickly.