Seed Sowing in the Snow

GROWING IN THE SNOW

Here in chilly zone 5b, I start all of my perennials, hardy annuals, and even certain vegetables in January and February, with no grow lights, no heat mats, and no seed-starting kits. How?

By winter-sowing the seeds.  Winter-sowing is a nifty method of outdoor seed-germination that involves nothing more than miniature greenhouses made from recycled containers and Mother Nature. Winter-sowing is the easiest, the greenest, and the most cost-effective way to achieve summer beauty. Learn how to build these greenhouses and start your seeds now, while you're buried in snow!

Kevin Lee Jacobs blogs at A Garden for the House. He was introduced to gardening when he was no taller than a delphinium. Today, his home in upstate New York features formal rose gardens outdoors and lavish window gardens indoors.

MAKE A GREENHOUSE

To start, make a greenhouse.  You can use just about any recyclable container for a greenhouse, as long as light can penetrate its walls. Gallon-size milk and water jugs are ideal.

Because winter-sown seeds will be watered by snow, sleet, and rain, the jug container will need drainage holes, and lots of them.

Start by turning your container upside down, and punch about 15 holes through its base.  Also, punch holes about a half-inch above the base, about three holes per side.

I find the easiest way to make openings in a plastic container is with a red-hot Phillips screwdriver, heated over a gas flame at the stove. If you don't have a gas cook-top, heat the screwdriver with a culinary torch. Otherwise, use an electric drill for your hole-making.

MAKE A HINGED LID

Next, make a hinged cover.  Just below the base of the handle, cut almost all the way around the jug, leaving a half-inch hinge, as pictured here.

I use a pen-knife to make my initial cut, and then finish the job with scissors.

PLANT YOUR SEEDS

Add soil and plant your seeds. Pour the soil to a depth of 3" to 4", then moisten thoroughly and let drain.  It is absolutely necessary to use a soil mix that drains well and that has a light, fluffy consistency. Commercial peat and perlite mixtures work well.

To plant, simply sprinkle your seeds on the surface of the soil. Tiny seeds, including creeping thyme (Thymus serphyllum), require no additional soil to cover them. Just leave them on the surface, regardless of what the seed packet says.

Larger seeds, like morning glories and sweet peas, require only a 1/8" planting depth. Gently pat the mix down, to make sure that seeds and soil make good contact. Then replace the lid, and secure it with a strip or two of duct tape, as illustrated at left.

LABEL YOUR PLANTS

Be sure to label.  Use a permanent marker or paint-pen to label your greenhouse with what it contains.

There is nothing worse than finding, in spring, dozens of miniature greenhouses brimming with hundreds of seedlings, and not having a clue as to what they are.

BRING IT ALL OUTDOORS

Regardless of weather, carry your greenhouse outdoors. Select a location that is safe from strong wind, but where sun will shine and rain and snow will freely fall.

My assorted greenhouses go on the patio table, out of the reach of Lily the Beagle who would otherwise knock them over.

RELAX!

Now sit back, and let Mother Nature do her job. As the weather chills and warms, your seeds will freeze and thaw.

These natural actions loosen the seed-coatings. This is why advance soaking or nicking of hard-shelled seeds, such as morning glories and sweet peas, is not necessary when you winter-sow.

WATER THE SEEDLINGS

When spring’s warmth arrives, but while the nights are still freezing, your seedlings will begin to emerge.

This is the time to check for water. Remove the tape, and flip open the top of each greenhouse. If the soil appears dry, moisten it thoroughly but gently, to avoid disturbing tender root systems. Then close the tops again.

On warm, sunny days, I open the tops for hours at a time, and let the seedlings enjoy the fresh spring air. The tops are, of course, closed at dusk.

PLANTING YOUR SEEDLINGS

Winter-sown seedlings, which are naturally hardened-off, can be planted into the open garden without any special prior treatment.

To transplant, simply cut a flap along one side of the greenhouse, and slide the clump of seedlings out.

Then cut the clump into pieces, as if you were slicing a tray of brownies. Plant as you would for any store-bought or indoor-grown seedlings.

BLOOMING BEAUTIES

Last year, almost all of the plants in my kitchen garden, shown here, were winter-sown.

Seeds of frost-tolerant flowers and veggies, including petunias, cosmos, kale, spinach, broccoli, and brussels sprouts were planted during the blizzards of January and February.

The frost-sensitive zinnias, tomatoes, and various squashes received milk jug-sowings in March and April.

Incidentally, I once conducted a test with tomatoes, sowing some seeds outdoors in milk jugs, and others indoors, under lights. Although the light garden plants emerged sooner, and were taller when I set them out, the winter-sown ones matched their stature in only a few weeks. 

HAPPY, HARDY PLANTS

Do give winter-sowing a try. I think you will find, as I have, that an entire garden of perennials, herbs, vegetables and flowering annuals—including the dreamy, Nicotiana ‘Purple Perfume’ shown here—can be obtained without wasting energy on light-systems, heating devices, or seed-starting kits.

And unlike windowsill-grown seedlings, which usually develop into frail, spindly things, winter-sown seedlings grow into strong, sturdy plants, naturally prepared for a glorious career in the open garden. 

Here are some of the plants I’ve successfully winter-sown:

Perennials and Hardy Annuals (including herbs)
Aconitum (monkshood)
Alcea (hollyhock)
Alyssum
Aquilegua (columbine)
Berlandiera (chocolate flower)
Campanula
Centaurea cyanus (bachelor’s button, shown at left)
Cosmos bipinnatus
Consolida (larkspur)
Delphinium
Digitalis (foxglove)
Iberis sempervirens (candytuft)
Ipomoea purpurea (morning glory)
Lathyrus odoratus (sweet pea)
Lupin
Nepeta (catmint)
Nicotiana
Oenothera speciosa (evening primrose)
Petroselinum crispum (parsley)
Petunia
Salvia officinalis (common sage)
Thymus serphyllum (creeping thyme)

Vegetables
Broccoli
Brussels sprouts
Cabbage
Kale
Lettuce
Spinach
Swiss chard
Tomatoes (If frost should threaten after seedlings emerge, cover the greenhouse with a blanket.)