With their beautiful scent and ability to provide endless bunches of cut flowers throughout the summer, sweet peas must be one of our favourite flowers to grow.

Caption: The more you pick sweet peas, the more flowers you get

They’re divided into two groups: grandiflora and Spencer types. For an expert, the distinction is in the ‘keel’ petals (the lowest two petals) – grandiflora types have a ‘clamped’ keel, while Spencer types don’t. For the rest of us the difference is that Spencer types have big, frilly blooms and, despite their name, grandifloras have smaller flowers and stronger scents.
Modern breeding has blurred these divisions. Nowadays, grandifloras are claimed to have both the big flowers and long stems we look for in cut flowers, as well as the profuse flowering and strong scent we love in the
garden.

Sowing
Sow seeds during October in rootrainers or deep pots using a Best Buy compost for sowing seeds. You can also sow in spring if needed.

Caption: Sow in October for strong plants that flower early

It isn’t necessary to soak or chit (cut or sandpaper the seedcoat) the seeds beforehand. Keep them at 16-18°C and they should germinate in 7-14 days. Mice eat sweet-pea seeds, so cover them with a propagator lid or sheet of glass until they’ve germinated. Once germinated, move them to a cool, sheltered position, such as a coldframe. Sweet peas like growing in cool conditions, but not being frosted. If it’s too warm they can become weak. 

Caption: Keep sweet-pea plants in a coldframe during winter

Planting and caring for your plants
Pinch out the growing tip when three or four pairs of leaves have formed, to promote healthy, bushy growth.

Caption: Cut off the growing tip to make plants bushier

Plant them out in April against a support, then tie in and deadhead them regularly to keep the plant producing blooms. When they eventually finish flowering, pull them off their support and put in the compost heap. 

Caption: Tie in sweet-pea plants to their support

Problems
Wet soils, warm days and cold nights can make plants drop their flower buds. It’s nothing to worry
about and they will soon recover as the nights warm up.
Sweet-pea viruses cause streaked flowers or mottled leaves. They are easily spread, so be sure to control aphids,
remove infected plants and clean secateurs between working on plants.
In dry summers, powdery mildew can become a problem. Keep plants well watered but don’t wet the leaves. Spraying with a suitable fungicide can slow its spread.

Caption: Powdery mildew usually occurs during dry summers

Pollen beetle sometimes hides inside the flowers. It doesn't damage them but it looks unattractive, especially in a vase. Cut the blooms and give them a sharp downward shake to dislodge as many as you can. You can also try putting the flowers in a dark room with a light source at the other end as the beetles should be attracted to the light and move. Lighter coloured sweet peas seem to be most attractive to them.

Caption: Pollen beetle hides inside sweet peas