Jumpstart your garden with winter sowing

In late-March/early April, the idea of clearing the snow-covered path leading to the greenhouse may seem daunting. But it's worth the effort. In this part of "A gardener's year" Anne Sandlund, from Ljusvattnet, provides the keys to how the greenhouse – or a candy box – can extend the growing season.

"Now it's really kicking off, just as I've been longing for!" exclaims Anne Sandlund as she embarks on the annual "excavation" of the greenhouse. It enables winter sowing—a "sneak start" to the gardening season.

"Now it's really kicking off, just as I've been longing for!" exclaims Anne Sandlund as she embarks on the annual "excavation" of the greenhouse. It enables winter sowing—a "sneak start" to the gardening season.

Foto: Morgan Bohman

Ljusvattnet2024-04-02 16:30

Twenty meters away, the greenhouse beckons Anne Sandlund. A mild March day, however, presents a challenge. With each step, she plunges thigh-deep into the wet snow.

Undeterred, she embraces the struggle. This annual trek signifies the start of the gardening season, a time she eagerly anticipates.

– Finally! she exclaims, a hint of triumph in her voice. 

– This is it, the beginning I've been longing for!

Shoveling away snow, Anne opens the greenhouse door. Winter sowing – a method to extend, or rather jumpstart, the short northern growing season – now takes center stage.

– Early sowing and harvests bring me immense joy, Anne emphasizes.

– The quantity might be small, but the satisfaction of enjoying homegrown food by the end of April – that's truly special!

Even without a greenhouse, you can sow seeds in winter. Small pots in a slightly larger plastic container work well.

For northern gardeners, greenhouses serve five crucial functions, extending their growing season and offering a haven for their precious plants.

The first benefit is early harvests. By sowing seeds in winter, Anne can enjoy fresh vegetables from her greenhouse as early as April and May.

Second, greenhouses allow for pre-cultivating vegetables before transplanting them outdoors for the summer season.

Third, they provide a warm haven for heat-loving crops that wouldn't thrive in the cooler northern climate.

The fourth function comes in late summer and fall. When outdoor temperatures dip, greenhouses offer a safe haven for a second planting of cold-resistant vegetables.

Finally, greenhouses can be a lifesaver against hungry wildlife. By bringing in autumn crops, Anne protects them from deer and other herbivores.

On this particular March day, Anne is preparing for a bountiful early harvest. However, the groundwork for this success began last fall.

– Before the ground freezes in the greenhouse we enrich the soil with aged cow manure and bokashi compost. This ensures healthy, fertile soil for when spring cultivation begins.

After sowing the seeds in cold soil, cover them with snow. This provides watering as the temperature increases.

Winter sowing, a technique for northern gardeners, utilizes the cold of the season to jumpstart their growing season. Seeds are sown directly into the cold soil within the greenhouse. If the ground is frozen solid, thawed indoor soil can be used as a temporary cover for the seeds.

Anne then adds a moderate layer of snow on top of the soil beds. As temperatures rise inside the greenhouse, the snow melts, providing gentle and even water for the seeds. This unique method promotes germination and fosters robust seedlings. The cold exposure strengthens them to withstand both future frosts and warmer weather.

Early summer brings rising temperatures. Be mindful that some fast-growing vegetables like dill, pak choi, parsley, radishes, and spinach may bolt (go to seed) quickly. Enjoy them fresh or move them to a cooler area to extend their harvest window.

Greenhouses aren't essential for winter sowing. A budget-friendly alternative involves repurposing candy boxes or grape boxes as mini greenhouses. Sow seeds in these containers, cover the soil with a thin layer of snow, and place them inside a larger box with drainage holes. Keep this bigger box in a shaded outdoor location. Ensure both the smaller containers and the outer box have holes for excess water to drain, preventing root rot.

Patience is a virtue for northern gardeners in March and April, when snow and ice are still prevalent. Anne advises patience. While southern Sweden might be further along in their growing season, it's still too early for many crops in the north.

– It's tempting to get a head start and sow everything at once. However, some crops need to wait. Consider winter sowing for early harvests if you're eager to get started early, but for most pre-cultivation, the end of April is the best time.

Winter sowing is a fantastic strategy for northern gardeners to get a head start on the growing season. By utilizing the natural elements – cold soil and snow – you can cultivate strong seedlings and enjoy fresh produce earlier in the year. So, embrace the winter chill and get ready for a bountiful harvest!

Potatoes are the world's fourth-largest crop.