WATER: RO, Rain Water, Misting, Watering
 

I have a 25 gpd RO unit and have recently moved from a 2'x4' orchidarium to a 12'x12' greenhouse. I find I need much more water to raise the humidity. I also found that even with vents, exhaust fan, and shadecloth I need additional cooling in the summer. I have excellent air circulation. I do not now have the ability to collect rain water but might be able to do this in the future. So, I have several questions as follows:

1. If I mist under benches for cooling during summer, should I use RO/rain water or is tap water ok?

2. Can I also use tap water to raise humidity?

3. Can I use RO/rain water interchangeably for watering?

I will be very grateful for answers or any other relevant advice.

I'd ask this question directly of Ray at Welcome to First Rays Orchids He has lots of first-hand advice regarding RO and misting and greenhouses, etc. He's an Orchid Board member of some renown.

In my opinion:

1. Misting under benches with tap water is OK. As it evaporates it will cool the air.

2. Your misting should raise the humidity and the tap water is fine once again. Don't forget, humidity is water vapor in the air. It is essentially distilled water when it condenses on greenhouse glass so there should be no problem.

3. Rain water and/or RO water is great for plants 99% of the time. The 1% of the time rain water wouldn't be that good is if it were polluted badly and that is not likely. I usually try to not collect the first few minutes of rain from my barn roof so any dust, bird droppings or whatever isn't collected.

Paul