How to grow Sweet Pea (Spencer Mixed)

Lathyrus odoratus

Also called Lathyrus

🌸 Flower 🌱 Grown each year

Frilly, richly scented climbing flowers for cutting from June to September. The more you pick, the more you get.

At a glance: Sow mid March to late April.

When to sow, plant and harvest

JanFebMarAprMayJunJulAugSepOctNovDec

Sow outdoors

Flowers

Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.

More to sow and plant in March and April.

Mid March – late April · 4 weeks before the last spring frost
Sow Seeds Outdoors
Sow thinly where they are to flower, in a sunny spot, into raked, weed-free soil. Sow 1 cm deep in deep root-trainers; soaking seed overnight helps.
10–21 days after “Sow Seeds Indoors” · Late March – early April
Check Germination
Seedlings should appear in 10–21 days. Keep the soil moist. If sown outdoors, thin them to 20 cm apart once they have two true leaves.
14–21 days after “Plant Out” · Early April – mid April
Pinch Out Tips (optional)
Pinch out the growing tip above the third or fourth pair of leaves for bushier plants with more flowers.
14 days after “Pinch Out Tips” · Late April
Add Support
Push in canes or twiggy sticks and tie in stems before they flop.
99–129 days after “Check Germination” · Early July – early August
First Flowers — Deadhead Regularly
Snip off faded flowers every few days to keep new ones coming for months. Take a photo for your journal!
Mid October – early November · around the first autumn frost
Clear or Collect Seed
When frost blackens the plants, pull them up for the compost heap. Leave a few seedheads first if you want to save seed.