Written by: Dottie Baltz
So what is Winter Sowing, you say?
Winter Sowing is a method of sowing perennial or hardy annual seeds during the winter.
It's as simple as that.
What makes it special is that you sow the seeds in recycled containers that have clear lids to imitate a greenhouse. The seeds are protected from Mother Nature and critters because of the lid. The soil also warms up sooner and the seeds sprout sooner due to the clear lids that are attached to the container. I generally sow my seeds in January because that is the time when I am ready for Spring to arrive and when I have the most free time. But you can sow them as late as March or even April. You can sow them earlier, but it's best to wait until temperatures are consistently in the 30s. You don't want any seeds to prematurely start to sprout. Another perk is that this method costs pennies compared to buying grown plants in the nursery. There is absolutely no fancy equipment to buy and no bulky light set-up to maintain in your home.
Please keep in mind that my method of Winter Sowing works best for zone 5 and with little modification, can be done in zones colder than 5 as well as zones 6 or 7. Winter Sowing techniques vary greatly in zones warmer than 7, so I can't comment on what techniques will work well for you. I imagine someone in a warmer zone, would not need to use lids on their containers. I learned how to winter sow my seeds from www.wintersown.org. I'm sure they can offer some additional information for these warmer zones.
Many people who do not have success starting plants from seeds indoors, have success with this Winter Sowing method. I was one of those people. You don't usually have the problems with low light or damping off that you might have indoors and the practice of hardening off the plants before putting them outside is virtually not necessary since the plants have been grown outside from the start.
- First you need to save some containers. I prefer to use take-out containers from restaurants because, generally they have plastic or tin bottoms and clear plastic tops. I also really like using the plastic containers that some fruits and vegetables come in at the grocery store. Generally, they already have holes in the bottom and top so you won't have to drill too many more and they are clear plastic. Some people use milk jugs and juice bottles, but I find them too cumbersome to work with since you have to cut the bottle/jug in half and then tape it back together once the seeds are sown. Do what works well for you.
- Once you have all your containers saved, make sure they are cleaned well with soap and water and sterilized in a1 part bleach, 10 part water solution.
- Once clean, you will need to poke drainage holes in the bottom of the container and air holes in the top. I like to use an awl to make the holes, but any sharp object will do. Be careful not to poke your finger. If you are using produce containers that already have holes in the bottom and top, you still may need to poke 2-3 holes in the middle of the lid to allow more rain water to get through.
- Once the containers are prepared, get yourself some sterile seed starting mix and wet it down thoroughly with warm water. I like to use warm water because it absorbs faster into the peat moss based seed starting mixes that I like to use. Once wet, fill each container and pack the soil in tightly as it will settle quite a bit over the winter months. If you are using a produce container, you may need to put a sheet of newspaper on the bottom or a coffee filter as the holes can be quite large. The paper will help prevent soil from coming out and it will also breakdown and enrich the soil over time.
- Now you are ready to sow your seeds. Generally, I just sprinkle them on the top of the seed starting mix then press them lightly into the soil, but if you happen to know the manufacturer's suggested seed sowing depth, use that. A good site to get information on seeds and seed starting is The Seed Site. Another good site can be found here.
- Once you are finished planting, place the clear covers on the containers. Most take-out containers snap on or can be crimped around the edges to secure them. If you decided to use bottles, then tape the bottle back together using duct tape. This is the best tape to use, as it will hold up in cold wet conditions.
- Label each container in two places. I generally put a piece of tape on the bottom and then write on the tape with a permanent marker, then I mark the lid as well. If the ink fades from the sun on the lid, at least the tape on the bottom should still be good. In the case of the larger produce containers, I usually write on a plastic marker and slide the marker inside the side of the container.
- Place the containers in a partially shaded area. I put mine on a picnic table. If you have pets that roam the yard, you may want to put them in an area they cannot get into.
- Now all you have to do is wait until Spring. Once the seeds start sprouting (between April-June depending on variety and your weather), check them every couple of days to make sure the soil is moist and that they are not growing too high for the container. As it warms up, you will need to make the air holes in the top bigger to allow more heat to escape and to allow more water to enter. I even remove the lids completely on warm days, and then cover them back up for evening. As temperatures warm up, you may have to water them daily.
- Once the seedlings have gotten their first set of true leaves, you can transplant them to their own pots to continue developing their roots. This is where all those nursery pots you've been saving come in handy. I especially like the 4" diameter pots. After a couple of weeks, I will also give them a shot of organic fertilizer, at half strength.
- Depending on varieties, most can be planted in the garden mid-late summer on into the fall.
If you'd like a list of seeds suitable for Winter Sowing, go directly to the Wintersown.org site.
You can also view my original Winter sowing Diary here in a pdf format.