C wrote:

How close do fluorescent lights have to be to indoor propagation trays to
be effective? I would like to use the ceiling lights I have in the
basement. If I were to set up a couple of sawhorses with propagation
mats, do you think I could get by with the ceiling lights, or will I have
to lower them to within a foot or so of the seeds?



As close as possible. Maybe even closer. Not touching.

When I used lights for starting in the basement, I used two shop lights
mounted right next to each other. I could get 4 flats under the pair of
lights. I would set the flats on a stack of newspaper to place them as
close as I could to the lights. As the plants grow, you just take out
sections of newspaper to lower the flat. The newspaper absorbs spilled
water. The fluorescent bulbs are not as hot as incandescent, but they do
generate some heat. If a plant grows into the lamps, you have a half a
day to a day to get them out before they start burning (actually just
drying out, not actually catching on fire).

Some plants always got leggy anyway. I find that sunlight is far and
away the best way to start plants. Much better than lights (although I
haven't tried the high intensity greenhouse lamps). A couple of trial
runs will tell you which plants can be done under lights and which need
real sunlight (depends partly on where you live).

Another problem with starting plants in the basement is damping off.
This is caused by high humidity at the point where the stem comes out of
the soil. The humidity encourages growth of funguses that kill the
plant. If you place a fan in the room so that air circulates, this
reduces the problem significantly. You don't have to blow the air onto
the plants, just keep the air moving. Leave the fan on all the time.

For tomatoes, a common practice is "brushing" the plants. This is
basically moving the plants around by running a brush over them, first
one direction, then another. The mechanical stimulation of the stems
strengthens them and makes them thicker, so that they will withstand
wind better when they are transplanted outdoors. Once or twice a day. I
have around 50 flats of tomato plants. I use a leaf blower on them to
strengthen them. A smaller quantity of plants can be done easily by
hand.