While many gardeners sow sweet peas in autumn for an early start, they can also be successfully sown from April onwards which is ideal if you have limited overwintering space. Be sure to check in on our Instagram page for updates on how our sweet pea grow-a-long with the Scotland Grows’ columnists is going around the country.
To get the best from your sweet peas and enjoy a profusion of scented petals which both you and our pollinating friends will enjoy through summer and right into autumn, here are M.T. O’Donnell’s quick top tips.
As temperatures warm up, April is a perfect time to sow sweet peas in pots, under cover, or directly into the ground. Unlike autumn-sown plants, spring-sown sweet peas catch up quickly and are often less prone to winter losses.
Use deep pots or root trainers filled with peat-free compost. Sow one or two seeds per module, covering them with 2-3cm of compost. Keep pots in a cool, bright place such as a cold frame or greenhouse until they germinate which is usually around 10-14 days.
Choose a sunny, sheltered site with moisture-retentive but well-drained soil. Prepare the soil by incorporating well-rotted manure or garden compost. If your garden soil is heavy, consider planting them in raised beds or adding grit to improve drainage. In Scotland’s cooler climate, positioning plants in a south-facing spot will encourage stronger growth and earlier flowering.
Sow seeds 2-3cm (an inch or so) deep and 10cm (4in) apart, covering lightly with soil. Remember to try to protect from slugs and mice who love sweet pea seeds.
Pre-soaking Seeds
Some gardeners like to soak seeds overnight to speed up germination, but it’s not essential. Nicking the seed coat with a nail file can also help stubborn seeds sprout.
When seedlings have two or three sets of leaves, pinch out the growing tip to encourage bushier growth and more flowers.
If growing in pots, gradually acclimatise young plants to outdoor conditions before planting out in late May.
Sweet peas are climbers and need something to scramble up. Erect sturdy supports such as wigwams, trellises, or netting before planting out or at the same time as direct sowing to avoid disturbing the roots later.
Sweet peas are hungry plants. Feed fortnightly with a high-potash liquid fertiliser, like a tomato feed, once flowering begins. Keep the soil consistently moist, especially in dry spells, and don’t let it dry out to avoid powdery mildew.
A well-maintained sweet pea display can flower from June to September and even later with the right care.
You know what they say about sweet peas, the more you pick, the more flowers you get! Regular harvesting encourages continued blooming to fill your house with fresh bunches of pure joy.
If you are not picking the flowers regularly for display, remove faded flowers daily to prevent seedpods from forming, which signals the plant to stop flowering.
Apply mulch around the base of the plants to retain moisture and keep up with fortnightly feeding to sustain flower production.
Sweet peas are a joy to grow, rewarding even a little effort with armfuls of scented blooms. Whether you sow in pots or directly into the soil, give them sunshine, support, and regular care, and they’ll keep your garden filled with colour and fragrance all summer long.
Not all varieties are scented and the blooms come in every colour imaginable, so make sure you consider your choices or try a mix of different varieties and see which thrive best in your garden. Scotland’s unpredictable weather means that robust, weather-tolerant varieties with strong stems are ideal.
One of the oldest varieties, known for its intense fragrance and two-tone purple and maroon flowers.
A reliable favourite with deep purple blooms and a wonderful scent.
A classic choice with large ruffled blooms in a mix of colours.
Perfect for lovers of strong fragrance and traditional charm.
A striking marbled variety with red and white petals, excellent for cutting.