Should I filter rain water?
 

Hello everyone.

I've heard rain water is good for orchids and collected a bucket of it last week. When i poured rain water into a clear class jar I notice a lot of small almost transparent debris in it as well as small amount of dirt.

Should I use it as it is or clean it before using?

It is not essential that you filter it (after all, that debris is in the water that orchids in nature would receive).

I do filter mine, though. That is mostly because I deliver the rain water to the plants with a pump sprayer. (I don't want to clog the pump sprayer). If I was just using a watering can, I would not bother filtering.

I see.
Thank you orchid Whisperer for advise.

I have a setup that collects rain water from my roof. I have a diverter valve so the beginning of a rain can wash away any crap on the roof. After it's rained a while I open the valve to fill my storage container. I fabricated a pre-filter from a 5 gal bucket that I keep pond filter pads in to keep the worst out. That said, my storage container hosts a population of Ceriodaphnia which must have hitch hiked onto the roof on a bird as eggs and been washed in. There's always little bits of stuff floating in it as well, but this does no harm to the plants or fish I use the water for.

Thank you Subrosa for info.

I would speculate that the detritus one collects in an urban environment is entirely different from that in a forest. I'm not saying it's bad, unless the local air is polluted, of course, but it is different.

If you water your orchids with rain water, make sure you supplement your fertilizer with calcium and magnesium. Some fertilizers do not contain those nutrients because the manufacturers know that those nutrients are often in the local water supply. Orchids that don't get enough calcium will be very susceptible to fungus infections.

And the death of the tips of new growth.

Good addition, Tucker. Unlike most nutrients, calcium (and boron, maybe others) is not very mobile within plant tissues- once absorbed and used, it cannot be shared with new growth if the external supply is lacking, so it's a good idea to use a fertilizer formula or supplement to keep it supplied.

The debris filtered out of my rainwater is often an odd mix. Leaves, pine needles, bits of bark, chips of whatever the neighborhood squirrels have been eating in the trees seems to end up caught in the filter. Also random unidentifiable grit.

Occasionally odd things find their way in. I recall once having countless tiny, molted spider exoskeletons trapped in the filter. Probably a cohort of baby spiders hatched at the same time in a nearby tree, and were all molting at the same time.

None of this is harmful stuff. Ray is right though, it is probably different from what you find in forests.

I dig out any leaves or large debris but, otherwise, I don't worry about stuff in the water too much.

I only use rain water in my outside orchids and I dont filter it because... well, they're outside.:D

I toss mine out to get rained on directly through the warm season. Give 'em a good bath and a little dry before brining them back in when it starts getting too cold. The occasional acorn or fallen leaf has never hurt them --- just a matter of picking them off/out occasionaly.

Is it not recommended to collect rainwater in the city? I live in a big city and I might start doing that soon, but I was concerned about air pollutants adversely affecting my plants. Anyone have any clue if it could?

If Philly's air quality is no worse than Atlanta, go ahead & collect/use the rain water. If collecting roof runoff, you might want to let the rain to rinse off the roof for a while before you start collecting.