I have a green house in Indiana. I have plastic trays 20 inch by 36 inch by 6 inches deep. Would like to water easier than twice a day with a can. Want to use a pop bottle. Cut off the tops and prick a few holes in the other end. Then fill with my Aquaponic water and ta. Da. Anyone ever try this and if so how many holes Getting ready to play with a non planted tub?

Figure someone has tried this so why reinvent the wheel

bump!

[Edit: I haven't done anything like what you're talking about. It sounds like a fine idea, though. I just figured I'd chime in with a solution to the watering seedlings task that I do know...]

Another easy way to water seedlings in trays is by using capillary mats, like this: http://www.gardeningchannel.com/make-your-own-seed-capillary-mat-self-watering-trays/

I did something like that this year, but with cardboard. I put a few layers of corrugated cardboard in the bottom of my seed trays, maybe making a little less than a half inch thick layer of cardboard.

I water the trays every three or four days by lifting the corner of a flat of pouring water directly into the tray. About two or three cups of water, enough to make the cardboard nice and saturated. I don't fiddle with it, though, just dump. The top of the soil sometimes dries out, but if I lift the corner of the flap and there is obviously wet contact between the cardboard and soil, it's all good. It encourages roots to go deep.

It is working very nicely. The plants are happy, and it's easy and quick work. And it's so simple it feels like cheating.