What is winter sowing you ask? A natural, stress free, and easy way to grow plants from seeds ... outdoors ... in winter.
Your seedlings will be hardier and more robust than those started indoors, and you won’t have to worry about acclimating them to the outdoors. With winter sowing, you start your seeds outside during the winter and Mother Nature does the rest.
Instead of open seed trays kept indoors, you reuse plastic containers that you would usually just throw in the trash. The containers act like little greenhouses outdoors where the seeds will germinate at their own pace when they are ready, much like in nature. You are adding the protection of lids to protect the seeds from wind, heavy rain or birds.
What you will be doing, in essence, is stressing the seeds by cold stratification and adapting them to our climate from the start.
The “wintersown method” was developed by Trudi Davidoff. She didn’t have room inside to start seeds and decided to “go along with nature” and place her seeds, sown in recycled trays, outdoors to fend for themselves.
Although not a novice gardener, she was a novice at growing seeds. She knew that many plants reseed and germinate outdoors without our intervention, but she was still delighted to see that the seeds started at just the right time for each variety and had scads of seedlings to plant in her garden, already acclimated to the outside temperatures.
What you’ll need to wintersow are recycled containers with lids, or gallon milk jugs cut nearly in half so they ‘hinge,’ seeds and soil, preferably mixed with some perlite or a seed starting soil mix. That’s all. I saved table grape boxes from Costco that already have hinged lids or those big salad mix containers from the grocery.
Look for seeds of flowers you normally see in your area. In the Sierra Foothills, some flowers that can be treated in this way are, wildflowers, perennials, grasses, herbs and winter vegetables like broccoli, lettuce, carrots and peas. Save annual seeds for spring.
Columbine, Black Eyed Susans, Larkspur, Delphinium, CA Poppies, Coreopsis and Penstamen are some of my favorites.
Six steps to Wintersowing are:
* Clean the recycled containers well and then poke holes in the bottom, if they have none already.
* Add about two inches of potting soil to the container and sow the seeds
* Label the container. One way is to mark duct tape with the plant name and stick to the bottom. Or use a plastic picnic knife marked with a Sharpie.
* Water them well (saturate them) once.
* Put the lid on the container and place outside in a protected spot that gets only morning sun.
Now forget about them until about mid-to-late April. (This is my favorite part). Once the weather starts to warm up and is consistently above freezing during the days, check your containers regularly for any signs of growth.
The only care you have to take at this point is to make sure they stay out of the full sun and make sure the soil doesn’t dry out. Don’t worry about rain, don’t worry about cold and even snow. Your seeds are on their own and know what to do. If you’re like me, you believe seeds are little miracles.
Once the seedlings get tall enough where they are touching the top of the inside of the container, it’s time to remove the lids for good. Take the lids off or open them and let them grow free in the open air for a week or so. At this time, you might protect them from nibbling animals in a fenced area.
So, when can you plant them into your garden? Well, for most plants you will need to wait until after the last frost date to be safe. For us in the Sierra Foothills, that is mid-May, but if you have a greenhouse of any kind you can protect them there. You can wintersow all of January and February to get a jump on spring.