Nitrogen won't dissipate because it is a part of our air - some in some out. So you can put your water in jugs any time. During the rain- the water collects some dust from the air - so you can potentially have some organic material in it that will create some murkiness, it is not a distilled water. But it should not harm the plants.

I.

Thank you. I figured that anything suspended in the water, like dust, etc. will settle out to the bottom of the barrel. I know it is not pure. Used to wash my hair in it when I was a young woman....makes it nice and soft! Distilled water is pure water, this is not. But my violets love it. Hope I can get enough to last the winter! I have about 30 gallons now, and it's going to rain again later today, so I can get some more to top off the 34 gallon barrel in my garage.