What is winter sowing? I’m interested in gardening, but I don’t know how to even start. I want my kids to learn how to garden, but our window sill plants never make it, help! I want to learn how to winter sow a garden!
We are currently in our fourth year of gardening as a family with young children. Our family’s preferred method for starting a garden is winter sowing. Check out our winter sowing video tutorial here or continue reading for the text version.
What is winter sowing?
Winter sowing is a method for starting seeds in mini-greenhouses. It eliminates the need for grow lights, heat lamps, or needing to have your own greenhouse for starting seeds.
Why should I winter sow a garden?
Plants sown outside via winter sowing tend to be more hardy than those sown inside windowsills. The seedlings are in the elements from the beginning so they don’t need the delicate hardening process. They also have adequate light without the need for grow lights, thus are less likely to become weak or leggy. If the seed package suggests cold stratification, winter sowing is a great option because you plant before temperatures have warmed up.
When you winter sow your own seeds, you can order from seed catalogs or from seed trades and are no longer limited the big box store offerings. If you are planting more than a couple of plants, winter sowing can be a more economical route to starting a garden than buying all the plants from a big box store or nursery.
As a family we want our children to learn the science behind the lifecycle of plants so we like planting our own seeds. While some seeds we plant directly in the ground, others we like to transplant via winter sowing.
What supplies do I need to winter sow a garden?
- Empty gallon milk jugs or other larger clear plastic containers you can cut. Be sure to rinse these out first! I generally start collecting mine the month or two before I’m planning to sow. If your family doesn’t drink a lot of milk. Ask your neighbors to rinse theirs out for you!
- Heavy duty scissors or utility knife
- Drill (if you don’t have a drill you can always use a nail and hammer to punch drainage holes
- A scrap 2×4 or 4×4 1-3 foot long
- Good potting mix or seed starter. Any brand can work, just make sure it’s not the moisture saving kind.
- Duct tape
- Something to mark your jugs with that won’t erase in the sun such as an oil pen or something you can engrave numbers in such as aluminum tape or even an old pop can cut in strips that you can engrave using a pencil.
- Space outside to set your finished jugs where they’ll get sun
How to winter sow a garden in 8 easy steps tutorial:
The beauty of winter sowing is all these prep steps can be done over as many days as you need. The timing is quite flexible as you’re simply building miniature greenhouses to grow seedlings.
Step 1: Prepare the milk jug (or alternative greenhouse)
Take your rinsed out gallon jug and with a pair of heavy duty scissors cut just under the handle parallel to the bottom to create a flip-top. Don’t cut all the way, leave about an inch or two connected so you have a lid (the half with the handle) that you can flip open and shut.
Step 2: Make drainage holes in bottom of jug.
Using a scrap piece of wood, stick it inside the base so you have something to punch into. Drill some drainage holes with a 1/4 inch drill bit. I like to do about 4-6 holes, one in each quadrant of the jug.
Step 3: Add soil
You’ll want the potting soil to be wet, but not so soggy it becomes a liquid. I suggest wearing your gardening gloves for this step. Scoop and fill the bottom portion of your jugs with about 3 inches of potting mix. If your soil is dry, go ahead and add some water to saturate it well, just let them adequately drain before planting your seeds.
Be sure you’re using a regular high quality potting mix like Miracle Gro and nothing with the extended water conservation. Keep in mind this is the soil where your seeds will get all their nutrients for the early weeks so you will want to use good potting mix not just filler soil.
If you’re doing this as a family project the kids will love doing the dirt part, so plan accordingly so you’re not having to spend hours getting dirt out of their Sunday best.
The convenience of winter sowing is steps 1-3 can be done far in advance of planting. Because if you’re like our family, sometimes other work comes up and you get interrupted.
Step 4: Plant your seeds
Take a pinch of your seeds and spread some in then cover them. Different seeds like to be planted in different depths, so follow the instructions for whatever you’re planting. You’ll want to plant some extras here because not all of your seeds will sprout. When you transplant these into your garden you’ll use the hunk of seedlings method to transfer chunks with groups of plants versus the single plants you might be used to buying from nurseries.
Step 5: Label your container
After your seeds are planted put your marker in or label the outside of the jug so you remember what you planted. I highly suggest not skipping this step. Even if you think you’ll remember, unless you are literally planting only one jug, you don’t need the stress in 6 weeks of having to remember what you planted because you have seedlings you need to transplant.
Speaking from experience, permanent markers don’t hold up to the powerful sun so be sure to engrave something such as aluminum tape or a pop can using a pencil. Or use an oil based marker. This year I simply drilled small holes in the caps from the containers then dropped the cap inside since I was doing fewer than 10 jugs. If you’re planting a variety of jugs, simply number them then keep a notebook of what each number has planted in it.
Step 6: Seal the greenhouse
The last step is sealing up your greenhouse so it’ll maintain its humidity. Close it as best as you can and secure it with duct tape. It doesn’t have to be perfectly sealed. The looser the seal the more moisture will escape so you might have to water it in addition to the rain and snow.
Once sealed up, set them outside in the sun. Full sun if you have it (setting them where your garden space is keeps them out of the way). You don’t want them to tip over though in the wind, so set them all together and make sure they’re supported some. Tie a strap around them if the wind might try blowing them away and they’ll help keep each other upright. Don’t put the caps on because if it rains or snows you want them to get watered. Mother Nature will do her work. I periodically check mine about once a week if we haven’t gotten any precipitation to see if they have dried out too much. If so I just water them some through the lid (not undoing the tape).
Step 7: Open the greenhouse when there are sprouts.
When you notice sprouts you’ll want to uncover them so you don’t fry your tiny seedlings. Just be sure to close the lids again in the evening if your temperature is dropping near freezing. Generally you want to plant around the same time it suggests sowing the plant indoors. If you live in a northern climate you may be able to sow even in January. I live in zone 7 so I have to be more cautious of sowing too early because our winter temperatures tend to fluctuate with weeks in the 60s followed by weeks below 30.
Step 8: Fertilize if needed. Plant seedlings in garden.
Fertilize most plants around two weeks after they’ve sprouted if you aren’t ready to plant them in your main garden.
You don’t have to worry as much about hardening off the seedlings because they’ve always been outside in the elements.
Now that you know how to winter sow a garden, you’re ready to plant your plants in their permanent homes once they have true leaves and the ground temperatures have warmed up. When you’re ready to plant, gently break the chunk of plants into 3-4 clumps of seedlings to plant as normal.
Starting a garden for the first time this year?
If this is your first year to try gardening or you’re considering expanding your gardening space, be sure to check out our “How to Garden in 8 Easy Steps Guide” here.