Watering with rainwater: some questions

[JKeys]

Hello there,

I've switched to rainwater for some of my plants, and I'm just wondering - when I collect from certain "runoff" locations (for example, water collects much more under the edge of the roof than in the middle of the deck) there tends to be some dirt/sediment in the water. It is not rust, maybe just dirt collected as the water moves across the rooftop. Is it ok to water with this, or should I collect from an area where there are no sediments, like out in the open?

Thanks!

[WeirdGuySeattle]

I think its probably fine. I clean my gutters out like one time per year and a bunch of grit gets in there. Birds poop on roof, etc. I figure its like fertilizer, but extra weak. It washes out of the medium and doesn't burn your plants.

If it were muddy you might worry. In spring when the rain warms up sometimes you get these nasty algal blooms that smell like sewage or something - have fun with that .

[No-Pro-mwa]

I water with rain water. And yes I get some bird poop as well, like weirdguy I don't worry about it.

[euplusia]

I clean the gutter once a month with a dish scrubber.
I let the rainwater sit down a few hours, take the supernatant and discard the sediment.
Before using it I add some very dilute fertilizer.

[ronaldhanko]

We have such good water that I don't need it but used runoff rainwater for years.

[Orchid Whisperer]

I filter my rain water, but only because I do most of my watering with a pump sprayer (it allows more precise placement of the water beneath the leaves and on the growing medium). I do it only because I don't want to clog the pump. I use one of those reusable plastic mesh coffee filters and paper towel; these catch nearly everything.

My rain water is mostly free-catch, not roof runoff, but I think the roof runoff is probably fine (unless you have a copper roof). As others have said, all the bird poop, detritus, etc. adds fertilizer value.

I do think it is interesting the things that show up in the filter. One time, most of the particles were the shed exoskeletons of hundreds of tiny spiders (I am not making this up, and I'm 87.35% sure I was not hallucinating!!) I think they must have hatched in a nearby tree or something.

[No-Pro-mwa]

Not hallucinating huh... are you sure, tiny spiders... what kind of thing are you taking? Just kidding you kid. I'll bet you can get some good things in there but so far I don't think I have had a problem.

But if you are using a sprayer I can sure see why you would filter it.

[catherinecarney]

I use rainwater collected from my roof, and I do get a reasonable amount of "bycatch" (sediment, leaves, and so on). I figure it adds nutrients, and I haven't had a problem with the plants.

My storage system is a stock tub under one of the downspouts, so the water is open to the elements pretty much year round. I do get some algae in the summer (and daphnia/mosquito larvae which make great fish food), and find the occasional water boatman swimming around, but the ducks usually keep the bug population in check (and fertilize, lol).

I know that there are some who are worried about algae/fungi/bacteria in the water affecting their plants, but the thing to remember is that we don't grow our orchids in a sterile environment. Many of the microbes in the water may be beneficial, and even if we used "sterile" water for our plants they would still come in contact with all sorts of microscopic "stuff" since it's constantly circulating (in spore form) in the air.

Catherine

[Subrosa]

My rainwater collection system consist of an approx 300 gal container with a 5 gal bucket sitting on top full of pond filter pads. There's also a valve between the bucket and the collection container which allows me to bypass the collection container and feed into the normal runoff system. This is nice when we haven't had rain for a while as it allows the rain to rinse crud off the roof and gutters before I divert the water into the collection container. I still get little bits of leaf material in the water, but I'm not worried about it. My Lemon Tetras live in the same water and breed like flies.

[catherinecarney]

Subrosa--love your collection system (and lemon tetra setup). WHY don't I think of things like this???

Looks like I've got some work to do on my system come spring.

Catherine