How to grow sweet peas

Perfect for picking, fragrant sweet peas are easy to grow and come in a range of beautiful colours. You can grow them in pots or in the ground, training them up a frame for a beautiful display. Plant sweet peas near a seating area so you can smell them as you sit and relax in the garden. Or pick some for the vase – even a small amount can fill a room with fragrance.

Jump to...

• Where to grow sweet peas
• Sowing sweet peas
• How to care for sweet peas
• How to propagate sweet peas
• Pests and diseases
• Where to buy sweet peas
• Types of sweet peas to grow

Where to grow sweet peas

Plant sweet peas in an open, sunny position in a well-drained but moisture-retentive soil. Sweet peas are well suited to growing in pots – make sure you use a good, peat-free compost with a slow-release fertiliser mixed in.

When to sow sweet peas

You can sow sweet peas anytime from October to April. Those sown in autumn will enter dormancy in winter and then start into growth again when temperatures warm up in spring. They will flower sooner than spring-sown sweet peas. For a long display, sow successionally from autumn to spring, so you have sweet peas flowering from May through to August.

How to sow sweet peas

Sweet peas are easy to grow from seed in either autumn or spring. If sowing in autumn ensure you have the room to grow them on in a frost-free place until spring.

Sweet pea seeds germinate relatively easily. But you can help activate germination by nicking the seed coat with a knife, avoiding the 'eye' area. Either sow seed in 9cm pots (3 to a pot), in root trainers or trays. Sow the seed in a good quality, peat-free compost, and place in a cold frame or greenhouse.

When to plant out sweet peas

Plant out your sweet peas from late May, once all risk of frost has passed. Before planting, harden them off by putting them out in the day and returning them to a frost-free place at night. Pinch out the tips of young sweet pea plants when they reach about 10cm tall, to encourage bushy growth.

You can buy sweet pea plug plants in spring. Plant them in fertile soil beneath a support, such as a wigwam made of bamboo canes. Most sweet peas will grow to about 2m in height. Water in well until they’ve put on good growth. Space sweet pea plugs or pots about 20cm apart - don't worry about separating individual plants.

Watch Monty as he plants out sweet peas and explains how to plant out shop-bought plants. Learn why it's best to plant them out only once the soil has warmed up, and the benefits of giving them a good drink after planting:

How to care for sweet peas

Sweet peas require training up a suitable support and can be grown as cordons. They don't need pruning but if there are wayward stems that can't be trained up a support, you may want to trim them back.

Watch David Hurrion's No Fuss video guide to tying in sweet peas:

Start feeding with a high potash fertiliser, such as tomato food, when flowers appear. Regular picking will encourage more flowers and prevent plants from setting seed. Water sweet peas growing in pots, and during very dry weather.

Find out how to prolong your sweet pea crops, in Monty Don's practical video. Monty explains how picking at regular intervals will keep your plants flowering right through summer and into September. You'll also have a steady supply of cut flowers for the house:

How to propagate sweet peas

Sweet peas are easy to propagate from seed but there's no guarantee they will come true to type – they may flower in a different colour or have a different fragrance from the variety originally grown. Some pure-bred types will bear similarities to their parent plants, while F1 types will look markedly different. Still, it's fun to save seed and see what you get.

To save sweet pea seed, leave the seed pods on the plants until they have turned brown. Collect them on a dry day, remove them from their pods and store in paper bags in a dry place until you a ready to sow them.

How to take sweet pea cuttings

Sweet peas will root from cuttings taken from young plants, and grow on to produce identical plants that flower a few weeks later than the parent plant. Simply take a 10-12cm cutting from a plant with about six pairs of leaves, just above a pair of leaves. Dip each cutting in rooting hormone and then place in water to develop roots. After about a fortnight, the rooted cuttings can be planted into peat-free, multi-purpose compost. Plant them out once established.

Pests and diseases

Young sweet pea plants are prone to slug and snail damage. Try using beer traps, copper bands, or nematodes to control them.

Sweet peas can sometimes become leggy. Here, David Hurrion explains how to save them:

Great sweet pea varieties to grow

• Lathyrus vernus ‘Alboroseus’ – a hardy perennial bush-forming sweet pea that has tiny pink and white flowers in April. Reaches 35cm in height and spread
• Lathyrus latifolius ‘White Pearl’ – perennial climber with pure-white flowers from June to late August. Reaches a height of 2m
• Lathyrus odoratus ‘Matucana’ – hardy annual that is hugely popular and fondly known as the old-fashioned sweet pea. It has scented two-tone purple flowers in summer and is ideal for picking
• Lathyrys odoratus 'Lipstick' (pictured) - a wavy-edged, Spencer type with good scent
• Lathyrus odoratus ‘Lord Nelson’ – hardy annual grown for picking. Blue flowers with a highly rated scent in summer. Plants reach 2m
• Lathyrus odoratus ‘Painted Lady’ – hardy annual grown for picking. Bi-coloured blooms of pale and dark pink. Highly scented old-fashioned type. Great for early flowers

Frequently asked questions

Why are the leaves on my sweetpeas turning yellow?

Yellowing sweet pea leaves are usually caused by over-watering. On dull days, plants don't need watering every day as this can cause root rot. Your sweet peas may be salvagable – stop watering immediately and ensure they're not sitting in any water. Then, if plants recover, start watering again, gradually, checking the compost first to make sure it's not still moist.

Help! My sweet peas are leggy!

Leggy sweet peas are usually the result of too little light. If you can, move them to a brighter spot, and turn the pots regularly so the plants don't lean too much in one direction. Once plants are 10-15cm tall, use your thumb and forefinger to pinch out the tips. This will encourage bushy growth and should stop them being leggy.

Do sweet peas trail well?

Sweet peas are climbing plants and therefore don't trail well. If you try to grow sweet peas in a hanging basket you may find that they trail a little but then stop growing, or will put on growth towards the base, rather than at the tips. Some dwarf or patio varieties of sweet pea are said to trail better than conventional types, and could be worth a try.