There is always something new to learn in the garden. This winter I have been reading up on how to winter sow. Winter sowing is the planting of seeds in the winter. Yes, the winter. By planting seeds in winter they are subjected to cold temperatures as if they had fallen to the soil naturally from the plant. In nature, plants drop seeds in the fall, seeds lay dormant on the soil until temperatures are right for germination. Winter sowing is a way to mimic nature.
To get started you need to collect a few supplies. I collected four litre milk jugs and washed them out. You can also use empty clear salad containers or any clear containers that are large enough to hold plants. I am using the opaque jugs as they filter a bit of the sunlight.
Once the jugs are washed out take an exacto knife and cut drainage holes in the bottom of the jug. Your containers will sit outside all winter and get rained on. You want to be sure they have good drainage. I found that by slicing a 1/2″ hole in the bottom with the knife and taking scissors to cut it out worked the easiest. The corners of the jugs are reinforced and harder to cut.
Once you have your drainage holes it’s time to mark the carton four inches up from the bottom. Your container should hold about four inches of soil so the plant has room for its roots to spread. I used a ruler and marked where four inches of soil would come to.
Next take your exacto knife and cut from the back near the handle and around the middle of the carton keeping above the four-inch mark. Be sure to leave the handle attached by about two inches so you have something to carry it with. Once I had my cut started I used scissors for better control.
This is the exciting part! Its time for the soil. I used a lightweight potting soil but it would be best to use a seed starter mix. Large seeds don’t mind regular potting soil but fine seeds need a starter mix as its lighter and easier for the seeds to push their way up. Fill your container to the four-inch mark. Water the soil to moisten it.
Choose cool season plants to start with. Look at seed packages to see if they say cold hardy, perennial, direct sow in early spring or fall or self sowing. When I see these terms I think of poppies, Calendula, bachelors button, sweet peas, garden peas, broad beans, spinach, kale, lettuce, cilantro and arugula. To start I chose spinach and mustard greens plus I am trying two perennial flowers, Dianthus and Chrysanthemums. My hope is that the perennial flowers will germinate and flower the first year if I sow them during winter. Sprinkle the seeds on the soil of your container using the number of seeds you want for your garden. I will be transplanting my plants out to the garden once they have grown to the right size, usually when they have their second set of leaves. If you are transplanting you can plant as many seeds as you want. Cover the seeds with a bit of soil but not too deep. Once the seeds are planted be sure to label them with their name and date sown.
Once you have planted your seeds its time to tape the milk jug shut. It is recommended that you use clear duct tape. I could only find white duct tape in the Christmas shopping frenzy so it will have to do. I think the purpose of clear tape is to allow more light through.
Be sure to remove the caps from the milk jugs. Your mini greenhouse needs to breathe and let rain come inside.
I cut two pieces of duct tape and started taping from the back to the front. I used two pieces as opposed to one large one as it was easier to handle and I will want to open the jug to water as the weather warms. I also wrote the name of the seeds on the tape just in case the label faded in the sun.
When your jugs or containers are planted they should look like this. Store your seed packages in a dry cool place and place the jugs outside in a sheltered area. My biggest worry is that the jugs will blow away or tip over so I have them on shelving along the east side of our home. Avoid placing them in a north position as you want light to reach your containers. So the jugs are planted, caps off and the side is taped together. I was able to easily carry the jugs by their handle and place them outside. Leave the jugs outside even through snow. In the spring the temperature outside will have the seeds germinating when conditions are right. Your job is to make sure they don’t dry out. I see some advantages to starting seeds in winter. For one, you can grow many new plants this way and I will have more room in the greenhouse. I think of this as an expansion on the greenhouse. The winter sown seeds will acclimatize better than the plants I grow in the greenhouse. There will be no hardening off process when you want to transplant them. This is a big timesaver for me. Once the plants are growing you may need to lift the tops back on the jugs. By this time they will be ready to go in the garden and you can empty the jugs and save them for next winter.
My friend Amy over at Get Busy Gardening has been the inspiration for my first winter sowing project. To read more about winter sowing I recommend her post on Winter Sowing.
I hope to be able to bring my winter sown seedlings to my first garden class. Lets hope they grow. Now to collect more milk jugs as I have so much I want to plant.