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)
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
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.
Sow your seeds lightly on top and cover with another thin layer of soil; Matthew suggests 'crumbling' a small handful over your seeds.
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: