Rain is great for irrigating containers. Even Mother Nature uses it. ;o)

Al

I have four rain barrels, with attached spigots, and use this almost exclusively for my SWC plantings.

That is the same question I was going to ask. I know in the summer I can see all kinds of little critters swimming around in my barrel. So it shouldn't hurt to add these organisms into a earthtainer which doesn't have any good bugs to fight bad bugs in the rain water? If there are any. I hope that makes sense.

If you stop & consider how many creepy beasties are running around just under the surface of your gardens & beds that you can't see ..... A mosquito wiggler or ten won't hurt anything. It's not the literal bugs and insects that offer trouble - they break down into usable elements - like fertilizer, but their presence is so minute that you may as well consider they have 0 impact on your plant's nutrition. Look at all the plants that grow in marshes & swamps - the water is alive with micro-fauna. ;o)

If you're that worried, add a goldfish or two to the barrel & they will eat all the bugs and poop a pile of N that your plants are sure to appreciate.

If you were my kid, I'd tousle your hair and say, "You worry too much!" ;o)

Al

Al, If I was your kid you would be one old sucker! I'm 57. LOL That's pretty much what I thought but thought I'd ask. As a kid I grew up drinking water from a cistern that caught water off of our house roof. Dad said it was just fine to use rain water if the month of the year had the letter "R" in it. About every 2 or 3 years we would clean the cistern out. It was usually pretty good except for the occasional frog and I guess he didn't drink that much. Times sure have changed.

Ok then ....... so I'd be more respectful and wouldn't tousle your hair; but I'd prolly still clap my arm around your shoulder and tell you you worry too much. ;o)

Al

When the hair touseling and the cistern cleaning are all finished, I have some additional information to add to the discussion. First of all, I have to add that I do not use the rainwater DIRECTLY from the 55 gal collector. It is too far away and too cold, most of the time, to drag all of my flats out to fill 'em up and, when I get my SWC's out, they too will be too far away. Sooooo, I fill a 5 gal pail from the barrel and keep it in the shop where I grow my seedlings. It is warmer and easier to haul one pail than a bunch of smaller containers. Here is a picture of the bottom of my 5 gal pail, which was purchased new, after a few weeks of storing rainwater and refilling it a few times.

http://photos.gardenweb.com/garden/galleries/2009/04/mold_1.html?cat=container_gardening

And here is a close-up of one of the cultures.

http://photos.ivillage.com/images/photos/resize/gardenweb_Garden%20Galleries_1239825314085_817501D.jpg

Now, my question remains: Is this something I should be concerned about since the SWC has a reservoir that is, for the most part, inaccesable (sic) and is expected to feed my plant(s) for an entire season without INTERNAL maintenance?

I have not had the mold analyzed by any laboratory but I am certain that any mold, that would grow from rainwater that is stored in an undisturbed container for three months or more, cannot be beneficial to my plants.

I am all in favor of using the rainwater I have collected, but I am NOT going to use it in my SWC's. Well, maybe one...but just as a test case, mind you. I will keep a log on the progress of the plant in that container and compare it to identical plants in containers that do not receive rainwater.