By Sam Burbach, Education & Programming Coordinator – 03/20/2020


It’s the first day of spring and that means gardening tasks are starting to spring up and we’ll soon have more to do in our yards than we might have time for! One task that you may have already begun or might be thinking about getting into is seed starting! Seed starting is a great way to give our plants a head start so that they grow and produce well during our limited growing season.  

Seed starting can be done in a greenhouse, in our home with grow lights or a very sunny window, or even outdoors through winter sowing. Each method will give us a different result, come with a different set of advantages and disadvantages, and might work better for some seeds over others. 

Many of you might want to start seeds but are thinking, “I don’t have a greenhouse” or “I don’t have the space to start seeds indoors or the money to invest in grow lights” or even “I don’t have the time to coddle tiny seedlings!” All three are true for me, so I’ve been spending this winter using the winter sowing method.  

Winter sowing is a method of seed starting where seeds are planted in mini greenhouses outside during the winter months. The natural cycles of freezing and thawing help break through the seed coat, and when the conditions are right for each individual seed it will germinate and grow with the protection and assistance of its personal greenhouse structure.  

Some of my favorite advantages of the winter sowing method – 1. It’s low cost! The greenhouses are made of recycled clear plastic containers such as milk jugs and juice bottles. 2. It’s easy! The setup of the mini greenhouses is quick and easy, and once the seeds are planted, the whole greenhouse gets set outside and left alone until spring! 3. It produces strong plants that are already more tolerant of the outdoor environment than plants started indoors. 4. Winter sowing gives you a way to get your seeds planted when you can’t really do anything else in the garden, which also frees up your springtime to take care of other gardening tasks! The list goes on, but let’s keep moving. 

Different seeds need to be started at different times due to their cold tolerance, and although it’s officially spring, we can still use the winter sowing method. In fact, it is the perfect time to winter sow tomatoes!

Here’s how you can try it at home!

Use well-cleaned, clear plastic containers such as milk jugs, 2-litre bottles, or juice bottles – without their caps.
Poke several holes in the bottom and a few holes near the top to provide drainage and ventilation.
Cut almost all the way around the bottle approximately 4-inches from the bottom to create a container for the soil to go in. Leave about an inch or two of plastic uncut to act as the hinge to open and close the greenhouse. 
Fill the bottom portion with potting mix and thoroughly wet with water. 
Plant the seeds at the depth given on the package, cover up and press the soil down for good contact with the seeds.  
Close the container back up and duct tape closedLabel the container. Set in a sunny location that is not covered so that precipitation will keep the container watered

Caring For Your Winter Sown Seeds:

For a downloadable version of the care instructions, click here.

Downloadable Instructions:

For a downloadable version of the full instructions, click here.
For a downloadable infographic, click here.

Additional Resources:

Successful Winter Seed Sowing. https://extension.psu.edu/successful-winter-seed-sowing
WinterSown Educational. http://www.wintersown.org/index.html