Everything you need to know about growing sweet peas

sweet peas gardening advice
Expert advice on growing sweet peasyujie chen

Growing sweet peas is a worthwhile investment, as a flower farmer once told me that sweet peas were her fastest-selling flowers at market. Their success was down to their scent - it’s deeply nostalgic, taking people back to long warm summers.

As a grower, the delight of sweet peas is that the more you pick the more they flower. They are easy to grow, but it’s good to remember that they are heavy feeders and drinkers, so preparing your soil with manure or compost is a must, as well as frequent watering during dry spells.

Sweet peas need full sun, and sturdy structures to grow up, so pick your site with this in mind.

How to grow sweet peas

To help you understand how to grow sweet peas, read our guide with all the information you need to know, below.

We also have guides on how to grow lavender, how to grow tulips and more in our gardening advice section.

What month to plant sweet peas

Sweet peas are hardy plants and can be sown indoors between October and March. To help germination you can soak your seeds in tepid water overnight, or place them onto damp kitchen paper until they plump. Sweet peas can also be sown direct into the ground in April or May.

How to sow sweet peas

As sweet peas produce long roots shortly after germinating, it’s wise to sow them into either root trainers, long thin pots, or cardboard toilet rolls, which can accommodate this growth. Use a peat-free multipurpose compost or seed compost, and sow the seed to a depth of 1.5cm.

Be sure to water your seeds gently but thoroughly before placing them on a cold windowsill, in a greenhouse, or cold frame, ideally with a temperature around 15°c. It’s worth noting that mice are partial to eating the seeds, so you may need to protect them from these unwanted visitors with wire mesh or holly cuttings. Your seeds should take between 12-21 days to germinate, and in my experience they all germinate at different times, so it’s worth paying them a daily visit.

Once your seeds have germinated you can move them outside, as any cold will help them develop strong roots, but be vigilant to protect them from any frosts by bringing them inside when needed. Once four leaves have appeared on your seedling, you can pinch out the growing tip of the plant, to help encourage bushier growth.

Alternatively, you can sow sweet peas directly into the ground in April and May, so spring is the best time to grow them. I’d recommend sowing two seeds in each hole in case one doesn’t germinate.

sweet peas gardening advice

How do you care for sweet peas?

Plant out your seedlings in a sunny position. Sweet peas like well drained soil but as they are such hungry plants it’s a good idea to enrich your soil, by incorporating manure or garden compost.

As well as providing food for your plant, it will also help the soil hold moisture which, your sweet peas will love. If they are destined for smaller spaces or a balcony then choose dwarf varieties and a deep container, which will provide ample room for roots. Place some stones or crocs at the bottom of the pot to help with drainage.

It’s a good idea to have your support for the sweet peas in situ prior to planting. There are lots of different choices for supports from natural frames woven from willow and hazel, to home made supports from bamboo canes and twine, and metal stands and trellis. The important thing is that your support is strong enough to not be blown over in the wind.

Plant out your sweet peas 5cm from the support, with ideally at least 20cm space between each plant. This will help make sure they aren’t competing for food, and provide some room for air to circulate. After planting make sure you water your sweet peas in generously.

If slugs are a problem in your garden, you can surround your seedlings with sharp sand, and it’s also a good idea to poke in a few short twigs close to your seedlings to deter any birds that fancy a bite.

sweet peas gardening advice

As your sweet peas start to grow, tie them to your support using twine, this will become a fortnightly job, as they grow taller and taller. I like to feed mine regularly with organic liquid seaweed feed, or comfrey would work equally well too. In dry weather water them regularly to keep them healthy, and once they start flowering, daily cuttings will help you get the best out of your sweet peas.

Keep an eye out for any seed pods that develop and snip them off, until the end of the summer when you can let them dry and save for sowing next year.

Best sweet pea varieties

There is an abundance of varieties to choose from. If you are interested in growing cut flowers, I’d strongly recommend the Spencer collections for their long stems and larger flowers. For scent, Matucana, King Edward VII, and Painted Lady are exceptional. I have a soft spot for Blue Velvet which is a terrific dark blue purple colour coupled with a beautiful scent, and I’ll try growing Earl Grey this year, a purple and white stippled variety with a beautiful antique feel.

Everything you need to grow sweet peas:

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