Greenhouse: Misting Systems - Part 1, 0 by digital_dave

digital_dave wrote:
If you grow plants that thrive on high humidity, or live in an area where the Summers are particularly hot and dry misting systems may be for you. When water evaporates it not only absorbs heat (good) it also leaves behind anything previously dissolved within it. The major constituents in “normal” water are the dissolved minerals such as calcium and magnesium, and metals such as iron and manganese. Other things such as chlorine, bacteria, viruses, organics are not unimportant, but for the purposes of misting we can ignore them.
In your water is (typically) hard, when it evaporates on the plants it leaves behind calcium carbonate (limestone) which can plate out on the leaves (bad). For this reason I use a mixed bed anion/cation water softener that reduces mineral hardness to practically zero. Reverse osmosis systems (becoming cheaper by the day) are also effective (no quite as good but much cheaper). You cannot use a salt-based softener since it removes calcium hardness for sodium (really bad). Other systems that can avoid water actually getting on the leaves can do without the costly softening process. Picture is of the mix-bed softeners (rented from Culligan). They must be regenerated every 1-3 months depending on usage.