At 11:17 PM 2/15/04 +0000, peter wrote:
i collected a number of paperbark maple seeds (acer griseum) last fall and
stuck them in the freezer over the winter.
i have a couple of questions about getting these seeds to germinate and
hopefully grow into trees (albeit small ones in a pot) in the future.
firstly, what is the ideal medium to sow seeds in?
i have previously tried peat pots but had no luck as it appears that the
peat pots remained so wet that the seeds rotted.
secondly, when would be the best time to sow these seeds?

Peter

Acer griseum can be somewhat difficult. Hopefully they weren't too dry
before you stored them. These have impermeable seed coats, so it is
probably best to nick them first. This is best done with pair of concave
cutters. Take a small slice out of the seed coat without damaging the
kernel inside. I haven't thought about this much, but you probably don't
have to cut all the way through as long as you remove some of that tough
glassy outer shell. All you are trying to do is create a way for water to
get into the seed. This can also be done by soaking the undisturbed seed
coat in Muraitic acid (as it comes from the hardware store for pool or
concrete treatment). Soak for about 15 minutes, then rinse them thoroughly.
Be very careful with acid and follow all the precautions. You only need
enough acid to cover the seed, so don't get carried away.

Next, soak the seed overnight in warm water (it doesn't have to stay warm).
Rinse and repeat this process one or two more times. Drain off all the
excess water. Mix the seed with an equal amount of DRY vermiculite. Put the
mixture in a ziplock bag and then in the refrigerator (NOT freezer). Keep
it there for 3 months. Take the seed out and sow it. The medium doesn't
make a lot of difference as long as doesn't stay too wet. I sow Acer seed
in my regular bonsai mix. Do this outdoors under bright light, but not
direct sunlight (if you have sunlight up there). I place the see on top of
the soil, lightly press it into the mix, then just barely cover it with a
little bit of finer mix or vermiculite or peat moss, enough to keep the
seed moist.

It should germinate within a few weeks. If it doesn't, chance are that the
seed wasn't viable. That's a common problem with Acer griseum. Cut a seed
open with your concave cutters and examine the kernel. Often the seed coat
is empty with this species. If there is a kernel, it should be creamy white
and solid, but not chalky or dry looking. If it is dark and/or very soft
and mushy, it is rotted.

If the seed is still viable after three months, but still not germinated,
return it to the refrigerator for another 3 month moist pretreatment, then
back outside to 70F again. Acer will sometimes require multiple pretreatments.

Brent in Northern California
Evergreen Gardenworks USDA Zone 8 Sunset Zone 14

http://www.EvergreenGardenworks.com

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