Grow Scented Sweet Peas
In warm areas, sow seeds in the autumn; in colder parts sow in spring in a warm greenhouse or on a windowsill. Plant outside in an open, sunny area.
When to Plant: autumn or early spring
At Their Best: summer
Time to Complete: 2-3 hours over several months
- sweet pea seeds
- sharp penknife or nail clippers
- deep seed trays or root trainers
- seed soil
- well-composted organic matter
- obelisk or bamboo canes
- garden twine
- all-purpose liquid fertilizer
Chip the Seed
Sweet pea seeds have a hard shell, and unless water can penetrate it, the seeds won't germinate. To ensure the seed absorbs water, use a sharp knife or nail clippers to carefully nick it opposite the "eye" (small, round scar) and remove a small piece of the seed coat.
In fall in warm climates, fill trays or pots with seed soil and sow the seeds 1/2 inch deep. Keep the seedlings in a cool greenhouse or cold frame until the following spring, only providing extra heat during severe frosts. In mid-spring, remove the tip of the main shoot from each seedling.
If you sow sweet peas in early spring, grow the seedlings indoors, or in a warm greenhouse, at 58–62 degrees F. When they reach 4-6 inches high, remove the tips down to the first set of leaves. Pinching out the tips like this encourages side shoots to form.
Harden Off and Plant Out
Fall-sown seedlings can be planted out directly into the ground in mid-spring. Spring-sown seedlings will have tender shoots that need to be hardened off for a few weeks by bringing them outside by day, and inside at night. Plant hardened seedlings out in late spring.
Enrich the soil with organic matter and plant one or two seedlings close to the base of a suitable support and tie them in loosely. The tendrils will soon take hold of the supports as the plants grow. Water during dry spells, and apply a liquid feed every two weeks from midsummer. Pick the flowers regularly to encourage more.
Top Tip: Homemade Seed Pots
Roll folded newspaper around a glass and tuck the top ends into it. Remove, then flatten the tucked-in ends to form the base. Plant seedlings and their pots into the soil — the pots will just rot away.
Sweet Pea Supports
Sweet peas climb using their twining tendrils, which cling to slim supports, such as sticks or bamboo canes. These bushy plants reach up to 6 feet tall, so make sure your support is tall enough to accommodate them.
Wooden or metal obelisks and tripods are ideal for sweet peas, and make decorative additions to flower borders or to vegetable beds. (Don't confuse the pods with green beans when harvesting: sweet peas are poisonous.) You may find that young plants struggle to take hold of smooth materials, such as metal, or don't cover the whole support evenly. To remedy this problem, wind some string around the poles and tie it horizontally across the legs of the support to provide the plants with more grip.
Make Your Own
It's easy to make your own sweet pea supports by setting out bamboo canes to form a wigwam and tying them securely at the top. You can also grow them up pea sticks or create a support with plastic mesh wrapped around a circle of sturdy stakes driven into the ground, securing the trellis with garden twine or wire. As the plants grow, these supports quickly disappear beneath the flowers and foliage.