First winter resting a dendrobium in S/H, is rainwater ok or should I switch to RO?

[bateaux_mousse]

I was just reading in another thread that resting dendrobiums should get zero nutrients. It got me thinking that even without added ferts the rainwater I collect passes over my roof and whatever's in my gutters, and has to be picking up some nutrients from the decaying leaves. Should that be insignificant enough that I can keep using it, or should I switch to RO? Or maybe just run my rainwater through a filter?

[Subrosa]

I wish that weather would permit me to use rainwater year round! I would just make sure that my collection vessel and gutters were clean after most of the autumn leaves were down and disposed of.

[Ray]

Avoiding nitrogen it the key.

According to a couple of university extension service articles I've scanned, the nitrogen content of composted fall leaves is on the order of 0.5-1%, so while I would agree with Subrosa about clearing leaves to minimize the exposure, I really have to wonder if rain flowing past relatively intact leaves would pick up much, if any nutrients.

[Paphluvr]

I always thought my orchids grew better with rain water, but I only collected when there was a heavy rain and even then waited 15-20 min. before collecting, in order to wash pollutants off the roof. I don't have the system to do it now so I have to rely on RO.

[bateaux_mousse]

Thanks everyone, I'm probably overthinking this. I know there is always some decomposed material in my gutters as I have maple trees that fill them with leaves and seeds constantly. I use a shopvac extension to clean them (me and ladders don't get along) but I know it doesn't do a great job. Still, sounds like nitrogen should be very minimal.

[Fairorchids]

You do not mention which type of Dendrobium. Their winter 'rest' requirements differ considerably.