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Winter Sowing is using plastic milk jugs or other plastic containers, and using them as mini-greenhouses outside in the middle of winter, to sow your seeds. I first read about Winter Sowing, here on Kevin Jacob’s blog. I have been doing this now for the last 5 years or so, and it has worked so well for me, that I wanted to share the idea in hopes that it works for you too. Because it is SOOOOO EASY!!!!! Sow those seeds, and then forget about them for a few month! Seriously. That is all. To see how I also start seeds the traditional way, using all sorts of equipment indoors, please see my Essential Seed Starting Equipment post.
I like to use milk jugs for my winter sowing containers. To prepare them, first, poke a bunch of holes in the bottom for drainage, and a few holes around the top for extra air circulation. I use a Phillips head screwdriver that I heat up over a gas burner, than just poke it thru the plastic a bunch of times. Then you cut the milk jug almost all the way around about 4″ up from the bottom, but leaving an inch or so intact opposite from the handle, as a hinge. So that you can lift the upper part of the jug open. I use an X-acto knife to do this.
Fill the bottom part of the jug with 3″ of damp potting soil. I use the same kind of potting soil I talk about in my Seed Starting Equipment post. Have some duct tape or similar tape on hand, that you will need to seal the lids closed. Also, stick a label in there also with the name of the seeds you are planning to sow. Plant the seeds into the soil as directed on the package for depth of planting. I tend to plant the seeds pretty densely, knowing that I will be dividing up the plants to transplant later in the spring. Spray with water so the top 1″ or so of soil is damp. Close the jug. Tape the jug closed all the way around. Make sure the original plastic lid that came with the container has been removed to allow for rain to get in, and the air to circulate out when it gets warm in there.
Set your Winter Sowing containers outdoors in a sunny location that will receive rain. Do not put under an eave which might prevent rain from entering into the open top. Then, just be watchful of really warm weather. If the seeds have germinated and you get an out of the blue HOT day, the plants may bake in there with the lid still on. So if you are getting some unseasonably warm weather, take the tape off and open up the lids. You may need to water them also. If it cools back down, tape them closed again. Then just watch. Once the plants are big enough to be filling the jugs with their greenery, it is time to pop the tops off like I just mentioned. And transplant as soon as you can for what you have grown.
I like to grow my own perennials and annuals using winter sowing. I tend to start out with hardy perennial seeds first, as early as January. Then I plant annuals and more tender perennials later in March. Winter sowing flowers & perennials is a great inexpensive way to grow your garden. Save your own seeds, or exchange seed with friends or family and grow your own.
I like to start my cold season vegetable crops in February. Then by late March they should be ready for transplanting. You could even try some warm weather vegetables like summer squash, winter squash or pumpkins in April. You could also start your cucumbers and melons in April as well. I have not tried warm season crops like tomatoes and peppers using winter sowing, but I bet it would work also.
I am in gardening zone 8b, and these are winter sowing methods that have worked well for me here in the PNW. Please let me know if you try this growing method and what you plant when! I am anxious to hear how you all do!