Three times in the past several weeks I have been asked to write about winter seed sowing. (Was there a recent article on the subject I missed?) The general rule of garden column writing is that if you get asked a question just once, you try to answer it directly. But if you are asked a question several times, then perhaps the answer should appear in a column.
So, winter seed sowing. It is not what many think it is. This is not another column about buying grow lights under which to start this season’s seeds. No, this is about planting seeds outdoors during the winter in such a fashion that they germinate in the spring and can be planted into the garden without hardening off.
In addition to an “automatic system” that doesn’t require lights or any care, winter seed sowing produces very sturdy seedlings. And you don’t need lights or a watering schedule. Probably the best thing is you don’t need indoor space dedicated to seedlings.
The downside to what sounds like an ideal idea is the limited palette of seeds that work under the system, though many of them are standard Alaskan fare. This can also add a huge element of uncertainty due to warmer-than-usual winter weather or a return of a prolonged winter after a good period of thaw.
Still, winter seed sowing works with annuals, vegetables and certainly perennials, which need to be stratified — exposed to a certain number of days below freezing. Annuals include cosmos, marigolds, petunias, snapdragons, sunflowers. Vegetables include all the cole crops — broccoli, cauliflower, kohlrabi, Brussels sprouts, kale, cabbages — spinach, lettuces and Swiss chard.
Winter seed sowing does not entail direct seeding into the garden. Instead, seeds are planted just as you would if starting indoors — same depth, same good starting soil and in containers. The difference is these containers need to be translucent and, unfortunately, plastic — glass in the yard is never a good idea — and have lids. Milk jugs, clear deli containers and clear “clamshell” containers all should work well. They need ample drainage holes as well as ventilation holes on the top. And, most important, you must have four or more inches of clear space for the seedlings to grow up into. Basically, you are going to make a small terrarium.
Plant the seeds, water as you normally would and then make sure to label them. Next, take these little greenhouses outdoors to a spot where they will get rained on and snowed upon, but are protected from winds, which might blow them around. Obviously — or maybe it isn’t — place them where you are sure they will get sun.
Then, just leave the containers outside and forget about them. They will probably be covered with snow most of the winter. Sometime after temperatures warm a bit, the seedlings should germinate. After the birch leaves appear, you can transplant into larger containers if necessary, but as soon as the soil in your garden is the right temperature, you can plant without hardening off.
In a way, this is like starting seeds using a cold frame. It usually works and it really does save space if that is a problem. Still, there it is always a mystery as to germination. Our wacky, long, long spring can cause a failure, making this method somewhat inefficient instead of the cat’s meow.
In any case, we have plenty of winter left to try some seeds using this method. Check out what the web has to offer with regard to winter seed sowing and give it a try on a few kinds of crops. Just know that in no way does winter seed sowing relieve you of the need to have a set of lights, however. Just saying!
Jeff’s Alaska garden calendar:
Alaska Botanical Garden: Time to register for summer camp. Calendar the annual spring conference: Friday, March 11 and Saturday, March 12. Register for these and classes, workshops and viewing the Valentine lights at alaskabg.org.
Seed racks: They are here!
Thrips: Cover soil with newspaper. Let the surface of the soil dry so eggs can’t be deposited.
Houseplants: Inspect for scale, mealy bugs and spider mites. Applying Neem is probably the answer to any light infestations.