When you consider how seeds germinate in nature, it makes sense to sow our own seeds the same way.
In late summer, left to their own devices, seeds fall into the ground. They slowly get covered with leaves and other natural material ready to begin their long winter hibernation in the soil.
As the cold weather sets in and snow covers the ground, the seed toughens up and as spring sets in that little seed will emerge in its own good time, when conditions are perfect for it to start peeking above ground.
July through August (or, in the northern hemisphere, from December through January) is generally a ‘rest time’ for the annual gardener, so if you’re anxious to be ‘out there’ doing something, winter sowing is a perfect way to keep your green fingers active!
What is Winter Sowing?
Winter sowing is the process of setting out our seeds in old plastic containers, and leaving them until they emerge in the spring. The containers act as tiny ‘greenhouses’ protecting the seed from the harsher weather, but allowing enough cold to help them toughen up over the winter months.
When to Winter Sow?
The best time to winter sow is deep enough into winter that a warm spell won’t start to germinate your seeds. The ideal time in the Northern Hemisphere is December through January. I like to begin mine in the week between Christmas and New Year’s Eve.
What to Winter Sow?
You can winter sow annuals and perennials. Make sure they’re seeds that are acclimatized to your local soil type and climate zone. People have had success with everything from tomatoes to berry bushes. I live in Zone 7ish in the N. Georgia Mountains, so this year I’m sowing rosemary, sage, oregano and lavender for my herb spiral garden, golden currents as berry bushes to compliment the wild blackberries, black cumin and early spring greens like Brussels sprouts, cabbage, broccoli and Swiss chard. It makes sense that any seed that volunteers itself easily in your locality is a great candidate for winter sowing.
Winter Sowing Equipment
Transparent or semi transparent plastic bottles – old 2 litre water bottles, milk jugs, juice jugs or any kind of transparent container with a hinged lid are all great winter sowing vehicles. I prefer containers with handles, because it makes them easier to move around, you will choose what’s perfect for you from SLA [Stuff Lying Around].
How to Winter Sow Step-by-Step
- Clean containers — Wash out your jugs and discard the tops. The open top provides an air vent for your seeds.
- Cut containers — If not using containers with hinged lids, stick a serrated knife into the side of the jug, lay it on its side and cut all the way round, leaving about 1.5” [under the handle if using a jug with a handle] so that the top hinges open. (Figure 1.)
- Create air holes — Use a knife or screwdriver to poke holes round the bottom of the container. This is for drainage and is very important. If you don’t make drainage holes, your seeds will drown! If using a container with a hinged lid, poke a few air holes in the top of the lid.
- Add soil — Fill the bottom of the container with about 2” of soil mix. I used regular soil from a garden center, but you can use your own if it’s great soil, and I mixed it with seed potting soil and some cow manure and home made compost. (Figure 2.)
- Water the soil — with a mix of pee and water to give it some valuable nitrogen and leave the containers to drain. (Figure 3.)
- Sow the seeds — on top of the soil, in the same proportion you would if sowing them in flats. I use about 6 seeds in one 2 liter jug and 3 in a small liter bottle, or a few more in a flat hinged container.
- Cover the seeds — with another layer of soil and pat down lightly.
- Seal the container — Seal the cut edges of the bottle or container with light colored duct tape. Leave the top open.
- Label containers — using a laundry marker [better than permanent marker], write on the duct tape what the seed is, the date of sowing and any other info. I like to note where the seeds came from. Or, use a wooden stick that is large enough to write on and pop it into the soil, through the top of the bottle.
Write the info on a label and stick it to the bottom of the container, just to be sure. (Figure 4.)
- Set out and leave! — Set out the jugs in a spot that will get the winter sun. Do not leave them on your porch under cover. They want to experience all the weather conditions they would in nature. (Figure 5.)
If you live in a really cold climate, you can wrap a little hay between the jugs to keep them from totally freezing.
Forget about your containers until the spring and you will see them emerge, when they are ready. Most people experience a 75% germination rate, depending of course on the germination rate of the actual seed. If they are low germinators, plant more!
If you are trying this for the first time, it would be wise to start your seeds in the normal way in early spring so that you have backup if for any reason your winter sowing isn’t successful. Chances are once you’ve seen how easy this is, you’ll become a winter sowing devotee.