Click below to listen to my 2 min. Garden Bite radio show: Sowing seeds in winter – vernalization
Plant some seeds in a container that forms a greenhouse effect and set them outside. Cheap, easy and allows for the seeds to be ready to plant in your garden when the soil warms up!
What happens with this method is vernalization, a process in which frigid temperatures stimulate seed germination.
This can work for perennials such as delphinium and thyme for example (plants hardy to your climate zone which is mostly 3 and 4 for our cold climate gardens), native seeds such as milkweed and cold weather vegetables like lettuce, peas, radishes…even alpine strawberries can all do well.
You have your seeds, now you need your containers. You can use milk jugs or the mini greenhouse above. They’re super easy with no cutting or duct tape necessary and they are sterilized properly.
If you’re using your own containers, you need to cut them leaving a hinge to open and close.
With the milk jug method, you need to create drainage holes.
- Use a drill, scissors or a knife to create several half inch holes.
- Cut the jug horizontally about four inches up from the bottom starting on one side of the handle and ending on the other side of the handle, leaving a hinge that you will use duct tape to shut after planting.
- Add 3 inches of potting soil or seed starting mix.
- Add water to saturate the soil.
- Add seeds. You can overseed perennials, cold hardy annuals and herbs. With vegetables, plant 1 to 2 seeds per container.
- Cover the seeds with about a quarter inch of soil, spray with water.
- Seal them up or place the lid on the nursery container and set them outdoors in a sunny location.
This is Karen, she is an expert at Gertens Garden Center in Inver Grove Heights, Minnesota.