il Fri, 18 Feb 2005 15:11:45 -0800, Matthew Montchalin ha scritto:

A couple days ago I made the mistake of putting my tomato seedlings out
on a windowsill for direct sunlight, and a few hours later I discovered
they were all withered. (We've had a lot of sunlight here lately in
Portland, Oregon.)

I immediately removed them, and enclosed them in a humidity-containing
package (it used to be a doughnut package but I filled it up halfway
with potting soil), and hid it away.

The next day, 10% of the seedlings began to perk up again.

If I buy a photometer, how much light should tomato seedlings be exposed
to?

Is the real problem loss of water instead of too much sunlight?

It can be too much sunlight and its pal heat. If you think about how
seedlings start in the wild, they are protected by the bigger plants
and have quite a sheltered upbringing. Seedlings are more fragile
than a full grown plant and have less resistance to bad growing
conditons. The thing with windows is that they get incredibly hot.
You want a themometer, not a photometer, if anything. I protect them
with shade cloth or lacey curtains when on my windows, but even then
I watch the temperature as all morning in window light can be too
much for seedlings. At night they rested near the fridge cooler which
helped keep them warm on cold spring nights.

--
Cheers,
Loki [ Brevity is the soul of wit. W.Shakespeare ]