In article ,
Jim wrote:
On Mar 15, 11:07*pm, wrote:

In message
, Jim
writes
Hello,

Please forgive my ignorance, but I have a question concerning the
health of potted Black Cherry (Prunus serotina) saplings, and I hope
someone here can help.

For years I have been potting these small saplings and they have done
quite well outdoors. This year I potted some and brought them inside
and placed them under a 1000 watt metal halide grow light. They budded
and began to leaf out, but now the small leaves are appearing to
crumple and discolor. I don't know what I am doing wrong, but I cannot
afford to have them die on me. I wanted to bring them in to get a jump
on the growing season. Can anyone suggest anything? Watering or
fertilizer regimen, different light, number of light hours?

Thank you all so much!!

MH lights are very hot. *THe young leaves may be getting burnt or
dried out.

I have the light about 10" to 20" avove the tops of the trees at this
point. The recommended distance I believe is one to two feet, though
it does seem too close. However, I have an in-line fan running and I
do not believe that heat is the issue, as when I place my hand under
the light at just a few inches below it does not seem unusually hot.

I am trying so hard, but I cannot seem to find the answer. The soil I
used is potted top soil, and I think this should be fine. I have not
added fertilizer, only water about every two to three days.

It may be the dryness rather than the heat alone that's doing it then.
The fan as well as the heat could be contributing to very low humidity.
Also, the heat from MH's is mostly radiant heat. To find out how hot
they are, use a thermometer. Your hand has a blood supply that is
carting away the heat before it builds up.

You may be trying too hard. I used to live up near the northern limit
of P.serotina's range, west of Ottawa, where normal winter temperatures
dropped to -40 (F or C, your choice). While black cherries occasionally
grew into trees, they mostly grew as short scrubby bushes around rock
outcrops, covered with black knot disease, but blooming, fruiting and
persisting nonetheless.

I suggest you put your plants out, with a bit of shelter from the sun
for a few days perhaps. They can tolerate a lot of cold, even after
breaking dormancy. IIRC, while P.serotina's range extends far south
from here, it's at higher altitudes as it goes south, so even if your
seeds originated from further south, they'll likely be okay. I can't
tell where you are, but here in Toronto we had a record-breaking mild
winter, and spring is much further advanced than usual. The silver
maple (Acer saccharinum) across the street is fully budded and snowdrops
and botanical crocuses are in bloom.

If you're interested in North American Prunus spp, you may want to try
some others. There's a chokecherry that makes a nicely formed small
tree and blooms profusely and early. I don't recall its botanical
name right off, but there's a clone called Schubertii that's widely
planted as an urban street tree here. This species is at least as
cold-hardy as P.serotina and to my observation is resistant to black
knot, even when growing close to heavily infected black cherries.

I hope this helps. Let us know what happens.