pH balance

If basic conditions ? light, temperature and CO2 ? are satisfactory, and the plants still aren’t growing well, the problem probably concerns pH or nutrients.
The first thing to do is to check the pH, which is the measure of alkalinity or acidity of a substance. It is measured on a scale of zero, the most acidic, to 14, the most alkaline. Seven is neutral. Nutrients are most available in a slightly acid solution, from six to about 6.5, and this is the best pH range in which to grow plants.

Not only should the water pH be measured and adjusted after adding fertilizer, but the pH of the soil or planting medium should also be measured. If the soil or planting medium is highly acidic, the irrigation water should be adjusted to a less acidic level. Highly alkaline mediums such as rockwool and some western soils should receive more acidic water?nutrient solutions.

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