Winter Sowing

February 11, 2008

I’ve decided to try winter sowing, a method of starting seeds outdoors during winter for germination in the spring. It bypasses all indoor starting methods, including the dreaded damping off, and produces tough plants that are already hardened off at planting time. It’s very low-cost and apparently addictive.

There is a huge recycling aspect to winter sowing (WS) that helps keep the costs down. Many of the containers that people use are recycled gallon milk jugs and 2L pop bottles. Unfortunately neither of these two popular choices are suitable for my situation. In Ontario, all our milk comes in tetra pak cartons or plastic bags and I don’t buy pop in 2L bottles. I could steal bottles from my neighborhood on recycling day or find some large pop-drinking family though I would have to do that on a continual basis as most of the containers seemed like they are really only good for one season.

To WS using a milk jug or pop bottle, you get rid of the top cap, cut the container in half, cut drainage holes in the bottom half, fill the bottom half with at least 4″ of damp soil, lightly sow your seeds and duct tape the top half of the container back on. Then you put the container outside in the chilly, snowy weather and forget about it until spring. Once the seeds germinate you start watering the seedlings and venting the containers so your seedlings don’t cook inside their “mini-greenhouses”.

I decided on a more long-term approach for my WS using storage containers and plastic cups. The idea was to buy a clear or translucent bin, drill holes in it and fill it with many containers of soil. On one of my trips to the States (only a 20 min. drive away), I picked up two 124-quart storage containers made by Real Organized. They are 32″ x 19″ x 15.75″ in size and have a snap-shut lid and clear base for $9.95 each. Next, I bought twelve 5.5″ square pots and found out that one storage container was only big enough to hold ten square pots. There was also a 4″ space between the square pot and the inside wall of the storage container just asking to be filled up with the perfect container. I needed something tall, narrow and pliable enough to drill holes through.

On yet another trip to the States I found packs of six 7″-tall plastic tumblers on sale at Wal-Mart for $0.50 down from $2.99 (thank you post-holiday sales!) and bought 14 packages, really way more than I needed.

Here’s a shot of my square pots and cups in my storage bin:

It looked pretty good so I started getting ready to drill holes in the cups and the bottom and top of the storage container.

I had read about a gardener using a glue gun to make holes in the plastic cups and decided to give it a try. It didn’t stink as much as I thought it might however it made really wide holes with high walls inside the cup. Not very good for drainage. I got my boyfriend’s cordless hand-held drill, put in a 1/4″ bit and started drilling holes into the storage container and 7″ cups. Doing a clockwise rotation with the drill made the hole too fast and cracked the plastic. After a couple of test runs I decided the best approach was a counter-clockwise rotation pressing gently into the plastic, creating a slower entry point for a cleaner drainage hole. Here’s a shot of some of my earlier attempts (upper right is the glue gun attempt):

I was able to drill holes into about 20 cups and then moved on to the storage container. Here you can see the bottom of the storage container:

I was a little haphazard with the placement of my drill, realizing afterward that I should have been drilling my initial holes into the raised area underneath my palm as this would be where the water would accumulate for drainage.

Here’s the finished storage container bottom with 29 holes:

I then drilled 25 holes into the top cover for the storage container (not shown) and spaced them out evenly.

Next was to prepare the cups with dampened soil. I dumped some organic potting mix into my kitchen sink and sprayed with down with the water sprayer, getting a nice, even damping:

I filled up the cups with the dampened soil, gently knocking them on the side of the sink to settle the soil before topping up the cup. I prepared a few at a time and put them in a plastic bucket so that the water wouldn’t drip out while I was seeding the cups.

I had been looking for a suitable plant marker for each cup that was easy to label and sturdy enough to hold up through months of inclement weather. I didn’t have any used plastic containers or old mini-blinds that I could cut up into labels. I finally found a package of plastic knives that were perfect for labeling.

I didn’t know how many seeds to plant in each container and ended up planting 12 seeds per cup for the larger seeds, such as lupine and coneflower, and just sprinkling the smaller seeds evenly like columbine and parsley. Here’s a shot of a seeded lupine cup:

As I seeded the cups I transferred them outside:

In Storage Container #1, I have 10 square pots of:

  • coneflower, white
  • coneflower ‘Magnus’
  • coneflower, purple from Peg (2)
  • coneflower from Val (2)
  • cleome ‘Helen Campbell’
  • bee balm
  • aster ‘Green Leaves’
  • pole bean ‘Cherokee Trail of Tears’

and 7 cups of:

  • wild lupine (4)
  • columbine, purple
  • columbine from Peg
  • clustered bellflower ‘Marine’

In Storage Container #2 I have 14 cups of:

  • spinach (3)
  • wild lupine ( 8 )
  • lupine from Peg
  • coreopsis
  • parsely

The second container has room for 11 more cups that I will probably fill up soon with vegetable seeds. I also picked up another two containers and will need to drill holes into them too.

The containers have been out there for a good two weeks and have been snowed in:

I’m looking forward to the seeds germinating and seeing how my wintersowed seedlings compare to my indoor seeds that I will start in March/April. For now, they will stay out in the cold, freezing and thawing, for the next month or two.


8 Responses to “Winter Sowing”

  1. jodi Says:

    Great post, excellent pictures and explanation. I’m doing my wintersowing project this week (after we get some of the snow shoveled away after last night’s storm, that is. I hope that all your seeds grow nicely for you.

  2. […] and did an official tally of all the containers. I had been keeping pretty spotty records since starting in January and wanted to know what I had sown and when. Also, I had been inspired by someone in Zone 6 posting […]

  3. Donna Says:

    Thanks Kathy, I came across your project doing a google search on gardening. I had no idea this could be done! I live in zone 5 Michigan and we really need the headstart. You have really inspired me to try this next year. I started 5 flats indoors this year, but I could do way more using your method.

  4. Kathy Says:

    Awesome, Donna! Since you live in the States, you can start by going to WinterSown to get some free seeds! Just remember to stagger your seed sowing, starting with seeds that need scarification (anytime between December and January), then seeds that are hardy (sometime in early February) and then tender annuals (late February to early March). Of course, that’s more for my zone, which is USDA Zone 4. Good luck!

  5. Kay Says:

    Thank you so much for your informative and detailed instructions. My only complaint is that I was so looking forward to seeing your results. How did it turn out???

    I am in Sudbury, Onatrio and I plan on using your method. Thanks again.


  6. Lorene Says:


    Thank you for sharing with pics…very helpful.

    My question is simple…How do you remove the plants for transplanting with out damage to the roots?

    If using milk jugs do I cut or tear apart the mass group of seedlings? Any suggestions or pics?

    I have read all I can find on the subject.
    I’m sure I missed some.

    But I have not seen any pics or information on removing for transplanting.

    New to winter sowing I live in Michigan zone 5b.
    Thanks in advance.

    • Kathy Says:

      Hi Lorene,

      The plants can take a bit of bashing as their root systems are so extensive. For milk jugs, cut away the jug and tear the roots apart into chunks with your hands – it’s up to you how many pieces you want to divide the jug into. You can split it into 4 – 6 pieces and space each piece 6 – 8″ apart, just to give you an idea. On GardenWeb forums they call them Hunk-O-Seedlings (HOS).

  7. Lorene Says:

    Thank You Kathy for replying….I will check out the HOS

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