Leaving the water sit in open air would be to let the chlorine disssipate. Some cities are using chloramine instead of chlorine which doesn't dissipate and neither does florine, for that matter. All of those are not good for plants. I usually collect rainwater or snow melt for my houseplants and seedlings.

tj

The crusty sediment around the edge of the soil can be from the fertilizer your wife uses (if she uses any). Usually every 3 months I give my houseplants a good drenching. I put them in the sink and keep filling them with water to help get rid of that buildup. If it's really bad, you can do that more often.

Kat

The crusty sediment around the edge of the soil can be from the fertilizer your wife uses (if she uses any). Usually every 3 months I give my houseplants a good drenching. I put them in the sink and keep filling them with water to help get rid of that buildup. If it's really bad, you can do that more often.

Kat

Here in Barron County the water is hard. The mineral deposits build up around the faucets,on vases, planters, the tea kettle and the pets' water bowls. Very annoying, but it shouldn't hurt your starts. This is the same water that goes through the hose for the veggie garden(unless you have a rain barrel).
I do let the chlorine dissipate from the water I use for my houseplants and veggie starts, and we have an under the counter filter for drinking water, but it doesn't remove the minerals. I still have to soak the above mentioned containers in vinegar water regularly to remove the deposits.
One thing you could do is purchase distilled water for your seedlings. I keep distilled water on hand for my steam iron. It's around the same price as drinking water.

For seedlings, I would suggest using water vegetables have been boiled/steamed in. I use it because it's got extra nutrients (what was leached from the veg during the cooking process). I also use it for my houseplants every now and again because it seems to work like fertilizer.

Yes, the crusty edges are probably from ferts. Specifically, the salts used in synthetic ferts. Like mommie_rose mentions, you can use the water from veggies, just don't use the water from canned veggies- more salt.

tj

Interesting about the vegetable water. I have no doubt that roots take up more than just the simple elements of fertilizers. In addition, you may be feeding other soil flora and fauna that in turn helps plants grow.

Also, years ago there was a craze about using boiled water (after it was cooled) to water seedlings. The idea was, if I remember correctly, that without the dissolve gases in it, the water was more easily absorbed by the tender roots.

One thing that works great, if you happen to have one, is water from an aquarium. It is chemical free, and means I regularly do a partial water change in my fish tank which helps to keep it clean. And when I do a more thorough tank cleaning, all that fish poop is great fertilizer!