vase of sweet peas

My family heirloom vase waits all year for sweet pea posies.

Anyone who has spent a few growing seasons with me will tell you, sweet peas are my totem plant, a generational touchstone and possibly the most satisfying cut flower in my summer garden. It used to be that every year, right around Valentine’s Day, I would go through the ritual of soaking, sprouting, and starting seeds. Dreaming of the fragrant blossoms to come, no task was too fussy for my ritual offerings to the church of Lathyrus odoratus.

Then, a few years ago I came across Ardelia Farm where proprietors Thomas McCurdy and Bailey Hale grow more than 150 varieties of sweet pea on 50 acres in northern Vermont. After reading their online growing guide, I followed their advice. Not only were my starts sturdy and robust, the  seedlings flowered early, yielding and an even longer season of beloved cut flowers.

Bouquet of sweet peas

A bouquet of fragrant sweet peas — yes please.

Chill out

Today’s blousy sweet peas descend from a wildling discovered by a Sicilian monk in the late 17th century. Nearly 200 years later, the decidedly modest but powerfully fragrant flower made its way to England and sweet pea breeding exploded. Some of today’s varieties still bear the names of plantspeople, like Sutton, Eckford, and Spencer, who gave us the plant that we know and love today.

Which is a long way of saying that sweet peas thrive in England’s cool, damp climate, a familiar scenario to this Pacific Northwest gardener. The following approach to starting plants is common among English growers, with a hat tip to the Vermont farmers who kindly spelled it out for me.

Sweet peas prefer cool, even cold growing conditions. Starting seeds early in the year allows for the development of a sturdy root system. Beginning in early winter, start plants in a chilly basement, garage, or an exterior shed where temperatures hover around 50-55 F. That’s significantly cooler than most indoor temps.

prince of orange sweet peas

I’m partial to warm melon blooms, this one is possibly Prince of Orange.

Get planting

Sow seed about ½- to 1-inch deep in a well-drained, coarse potting mix. Deep pots are preferable to shallow growing trays. Ardelia Farm recommends that you skip soaking, nicking, or otherwise pre-treating seed to avoid exposing plants to fungal disease.

After about 10 days, longer if conditions are cooler, you’ll begin to see tiny sprouts emerge. At that point, move the seedlings (still in their pots) to an even cooler location, like an unheated greenhouse, a covered porch, or a protected location out in the garden. Provide full natural light, the more the better. Pro tip: Protect plants from mice, birds, slugs, and snails who can, and will, devour seedings in a heartbeat.

Sweet peas thrive when temps are around 45 F. during the day with overnight lows around 35 F. “No worries,” the Vermont sweet pea guys say. “A hard frost, right down to 20 F. is fine.” I guess they should know, Vermont winters run frigid. When grown cold, top growth on your seedlings will be short and stocky but the plants’ roots are actively growing.

Sweet pea plant

‘April in Paris’ is an especially fragrant sweet pea with nice cutting stems.

Out into the Garden

The experts at Ardelia advise planting sweet peas into the garden when you see daffodil growth emerging. Sweet peas are heavy feeders so amend your planting bed with plenty of manure, compost, and organic material. As the weather warms, your well-rooted plants will leap into active growth. To encourage robust branching, remove the top set of leaves, leaving 2 or 3 sets on the young plant.

Unless you’re growing a dwarf window box variety, you’ll need to put some sort of support in place to accommodate the clambering vines. Twiggy brush, wire fencing, or a teepee strung with string all provide purchase for the vine’s fine curling tendrils to cling to. It’s not uncommon for vines to reach 6 or more feet tall, so plan accordingly.

Once flowering begins, keep flowers picked to encourage more blooms. Eventually, summer heat shuts down sweet pea season – unless is doesn’t, as sometimes heat deprived Northwest gardeners can attest.