Stratification- The process that recreates the temperature conditions that would naturally break a seeds dormancy.
What is winter sowing?
Some seeds need a bit of cold to jumpstart their journey to the garden. This period of chilling and then warming, helps break down the seed coat leading to more successful germination and a happier plant overall. Perennials are big fans of this cold treatment and it's the reason we plant things like garlic in the fall! Though it can be recreated using a refrigerator, our preferred method is winter sowing. It's simple to do, inexpensive, saves space and doesn't require any fancy equipment. Plus, you won't have to worry about hardening off your seedlings which can be a delicate process.
It's an excellent way to beat the January blues. Each time you walk by your milk jug greenhouses, you'll be filled with a sense of optimism about the warmer weather ahead.
Here's what you'll need:
Plastic milk jugs, salad containers, or liter bottles. Remove stickers and labels - the tops need to be transparent!
A box cutter or good pair of scissors
Duct Tape (or similarly strong packing tape)
Labels/Markers
Soil
Seeds (scroll down to see what types do best)
Water - a spray bottle is helpful but not mandatory
A good spot with plenty of natural sunlight
and a little bit of patience
Directions:
If using a milk jug or bottle, carefully cut your container in half leaving the top partially attached near the handle (or on one side) to create a hinge - this will help to close your lid later.
Poke holes in the bottom of your containers using a screw or thumbtack to allow water to move through preventing soggy soil.
Fill the bottom with 2-3" of soil and water the soil.
Follow seed packet instructions for sowing depth.
Water lightly - this is wear a spray bottle comes in handy because the top layer doesn't need to be soaked.
Place your labels inside so they won't be destroyed by the elements.
Seal your container by closing the lid and (if necessary) duct taping the top half to the bottom half.
Place your mini-greenhouses somewhere outside where they'll get plenty of sun.
Now let nature do it's thing - time for you and your seeds to just....chill😎
Watch Matthew demonstrate how to winter sow in our latest YouTube Video:
Winter sowing is good for most seeds but not all! It’s a method that should only be used during the actual winter months. Once daytime temperatures remain above 50 and nighttime above 40, the conditions aren’t suited for this outdoor method – your seeds will likely overheat. For a full list, visit our collection page:https://www.superseeds.com/collections/seeds-for-winter-sowing
Pinetree Garden Seeds
March 01, 2023
Marie – Yup! You punch holes in whichever type of container you choose to use to allow for proper drainage.
Christine
March 03, 2023
Thank u, Matthew! Can this method b done with all seeds, such as flowers, summer vegetables, etc.?
Marie
March 01, 2023
Definitely want to try this method. I didn’t notice in the video but did you put holes in the bottom of the milk containers as well?
Sylvia Sutton
February 03, 2023
Never heard of it will tell my granddaughter we may try and start especially the lettuce she has rabbits thank you so much
Barbara Harrington
February 03, 2023
I love winter sowing and one of the best things is that you don’t have to harden off the plants before you put the plants in the soil. i’ve even started tomatoes successfully using this method.
Mardelle
February 03, 2023
Really enjoyed your Guide to Winter Sowing video and list of seeds to try. I am going to sow some seeds this winter. Thank you !!
Pat Stuckey
February 03, 2023
What is your frost date, and does it make a difference?
At this elevation (Colorado in general), we tend to have big temperature swings between night and day. Can the seedlings get too hot?
Would this work “in situ”? Could I create a little seed bed where I want the plant, and cut the bottom off the jug, and put it over a few seeds? The one problem I predict would be the wind – I might need something to weigh or stake an empty jug down.
I was planning on trying this with beans anyway. They do not need cold stratification, but something – I think birds – got most of my sprouts last year.
Barb
February 03, 2023
I’ve been winter sowing native perennials for six years in Cheyenne, Wyoming, and never tape my milk jugs closed. The plastic is flexible enough that the top can be jammed part way into the bottom. The gaps along the sides let the snow in—I don’t have to water the jugs all winter because I leave them in a shady spot until I see sprouts, usually sometime in April here. Then I move them to a sunny spot and keep an eye on moisture levels. By May I sometimes leave the tops off, but put them back on when there’s snow predicted.
Cynthia
February 03, 2023
We’ve been doing this for several years now and it works a treat! Makes growing from seed so danged easy. I taught my niece how to do it last year and she grew most of her garden that way. She’s a natural born cheapskate so it was right up her alley! :) I’ve got my supply of milk jugs hanging in the rafters of our barn and I’m itching to get started. Next week is the week!
Meaghan
February 03, 2023
So informative! I had no idea all these greens could benefit from stratification!
Joe hoesche
February 03, 2023
Thanks for the enthusiasm got my fire going going to start my cabbage soon try it ur way
Terese
February 03, 2023
This is so cool! Thank you!
Beth Piercs
February 03, 2023
I’d like to thank Matthew for this video. He makes it look so easy, and it is! According to your list of when to winter sow, is this for your area? I live in Zone 4b/5a snd I can get some pretty frigid days in January and February; sometimes in the minuses.
Mark Follansbee
February 03, 2023
This is a fantastic blog. Thank you for sharing this. What other seeds can we do this with? I would love a more complete list. Thanks again!
Joni Kucewicz
February 03, 2023
Thank you, thank you for the very informative and fun posts!! Happy gardening!!
Susan Scherschel
February 03, 2023
You dont have to only use cool weather crops, I have planted tomato seeds in zone 5b in late February and the germinated and started growing in March, we had freezing weather and snow but they did fine, best tomatoes I ever grew from seed!
Iolanda.Ferrante
February 03, 2023
I didn’t know what veg needed stratification.
Thank you very much.
Pinetree Garden Seeds
March 03, 2023
Hi Christine,
Winter sowing is good for most seeds but not all! It’s a method that should only be used during the actual winter months. Once daytime temperatures remain above 50 and nighttime above 40, the conditions aren’t suited for this outdoor method – your seeds will likely overheat. For a full list, visit our collection page:https://www.superseeds.com/collections/seeds-for-winter-sowing