I have hard water. What can I do about it?
— Desert Guy
Hello Desert Guy,
Hard water is definitely a big problem for growers. The very best solution would be to either use distilled water or reverse osmosis water. Because of your hard water, reverse osmosis requires that you also have a water softener, or the R.O. will fail quickly.
If you use distilled or R.O. water, you will need to add back a little calcium and magnesium. You can buy Cal-Mag at any garden nursery, hydroponics store, or grow store. Advanced Nutrients, General Hydroponics, Humboldt Nutrients, Earth Juice Elements, General Organics and Botanicare all make a good Cal-Mag. We use Botanicare. Other companies also make it. Only use 1/8 to 1/4 teaspoon per gallon of water. You may have to do this every time you water.
If you cannot use distilled or R.O. water, at least use something like a Pur water filter or Britta water filter.
We don’t suggest you automatically add the Cal-Mag back in this instance, but keep an eye on your plants for symptoms of calcium and magnesium deficiency. If you see a deficiency, use 1/8 to 1/4 teaspoon of Cal-Mag per gallon of water.
Below are a couple of pictures of what calcium deficiency looks like. Parts of the plant start to die and its growth becomes very stunted.