Tap, spring or demineralized water?

A question from a fellow grower:

What’s the best kind of water to use tap-spring- or demineralized ?

I use rain water, spring water would probably be better if readily available, tap water is fine but I wouldn’t use de mineralised

De- natrued water = tap water let standing out for 24 hours - work great never no issues !!

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It depends a little on how you are growing.

In hydroponics, demineralized, distilled, or Reverse Osmosis (R/O) water is usually best, and even when growing in many soils, these might also be best. Rain water has practically no minerals in it usually, after all it is nearly the same as steam distilled water.

The reason nearly pure water is often best, is that the minerals and other substances found in tap water or well water, and often even in many types of spring water, might have too many of certain minerals that could potentially cause problems with many plant foods/fertilizers. In many cases “hard water” will be very alkali and it could change the pH of the growing medium, and in a way that will cause the plants to not be able to use certain nutrients properly. In this case it would be called a pH related nutrient lockout. Sometimes these minerals could be in high enough levels to actually cause nutrient mineral toxicities, and the "over doses’ of certain minerals or nutrients can actually cause other nutrients to become unavailable as well.

If your tap water is 150 parts per million (PPM), this would be a Electrical Conductivity (EC) of 0.3, or lower, then you might not have any problems growing in most soils or soil-like media. If you are growing hydroponically, you probably need these numbers even lower, say below 50 ppm or 0.1 EC.

This just makes things easier in most cases, as you should have less problems with pH and you know exactly how much of what you are feeding your plants, as no extra minerals or other substances are sneaking in in the parts per million of dissolved solids.

There are also other things to consider with tap or well water, and some of these nutrient minerals can also build up in the soil and create what is known as a nutrient salt toxicity. This is not to be confused with table salt, sodium chloride, but this actually could be some of the dissolved solids in tap, spring or well water, and sodium is one of the bigger things to worry about in some tap or well water, as most plants are not very tolerant of it at all.

happy growing,


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