How to Sow Seeds in Winter for a Springtime Bloom

As autumn marches on around us and we slowly put our gardens to bed for the winter, the thought of sowing seeds of any kind seems months away. Surely this is a job for spring.

In reality, however, many seeds can be sown, or even need to be sown, in the colder months to be ready to sprout in the warmth of spring.

Many wildflowers drop their seeds naturally at the end of summer or the beginning of fall to go through the process of cold stratification. Some shop-bought seeds need to go through this process, too. You can force your seeds into cold stratification in the late winter/early spring, or you can help them along more naturally by sowing them outside in the depths of the cold season.

What Exactly Is Cold Stratification?

Many seeds, especially native wildflower seeds, actually require going through a process called cold stratification to germinate successfully. Perennial plants that disperse their seeds naturally at the end of summer or into fall drop their seeds to the ground so that they can experience the motions of frost and thaw throughout the winter.

This process ensures that the seeds do not germinate too late in the summer or early fall.  This would only lead to young tender shoots being killed off by frost. It also prevents them from sprouting too early in the spring, where dangers of late frost can also threaten delicate seedlings.

How to Winter Sow Seeds

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There are two different ways to sow seeds in the cold months. One is to sow directly into the ground, and the other is to sow them into closed mini greenhouse-like containers.

Mini-Greenhouse Method– This is a great option if you have old juice, soda, or ‘milk’ jugs. Clear plastic or translucent plastic bottles and jugs are required as these let some sunlight in. You can also use the plastic containers that storebought salads come in. If you don’t have a bunch of recycling hanging around, you can also use shop-bought clear plastic containers.

First of all, you need to make some drainage holes in the bottom of your container. Next, make an incision almost the entire way around the container about halfway up. You are trying to leave a hinge of sorts so that you can flip the top half of the container open and closed. Also, take the lid off the bottle or jug. This will allow some rain or even snow into the container.

Fill the bottom half of the container with potting mix or compost. Then, lightly dampen it. Next, sow your seeds into the soil according to the deep packet instructions. You can use a different jig for different seeds.

Now, you need to seal the jugs closed again with some tape, leaving the lid of the bottle or jug off.  It is very important to label your containers with the name of the seeds and the date.

Finally, place your containers in a sunny spot in your garden and leave them alone until the spring when they should start sprouting. It is at this time that you can start to transplant your seedlings out into the garden.

Direct Sowing Method– Many wildflower seeds can also be sown directly into the ground. This will need to happen before the ground has become unworkable by frost. Read the seeds packet for sowing instructions as many wildflower seeds need light to germinate.

When to Winter Sow Seeds

You can winter sow seeds at any time during the winter months. It is best not to sow too early in case there is an unusually warm spell that might trigger germination. You also don’t want to sow seeds that need cold stratification too late in the winter or they won’t get the cold time that they require. December and January are good times to try winter sowings.

Seeds to Use for Winter Sowing

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Most perennial seeds can be sown this way. Black-eyed Susans, echinacea, milkweed, and poppies usually need cold stratification to germinate. Other cold hardy annuals such as sweetpeas, calendula, snapdragons, and cornflower can be sown early for a head start.

Some cold hardy vegetable seeds can be winter sown, too. Get your brassicas, carrots, and spinach seeds in the solid in the depths of winter for a lush spring harvest.

Related Content:

• 8 Must-Read Winter Gardening Tips
• 10 Big Time Greens for Cold Weather Gardens
• 7 Vegetables to Plant in the Autumn for Harvesting Next Year
• What to Forage in Fall