How To Grow Sweet Peas

Sweet peas are popular flowering annuals that are ideal for garden borders, trellises and wire fences.

In this article, you’ll learn everything you need to know about growing and caring for sweet peas, so you can enjoy their beautiful fragrant flowers in your garden.

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sweet pea flowers


Sweet peas (Lathyrus odoratus) grow best in full sun but if you live in an area with hot springtime temperatures it’s best to choose a spot with some afternoon shade.

They prefer cool days and nights and will start to fade when the weather becomes hot in summer.


Sweet peas will grow in most soil types but they don’t like overly acid soils.

Check your soil with a test kit and add some lime to the soil if the pH is under 6. [1]


Try planting royal mix, multiflora mix or old spice mix for a beautiful colorful display.

pink sweet pea flowers


Sweet pea seeds are large and simple to manage so they’re easy to plant directly in the garden.

Most varieties germinate in one to two weeks after planting but you can speed up the process by soaking the seeds overnight in water to soften the seed coating.

You can also make a small nick in the seed coating with a piece of sandpaper.

Plant the seeds in late winter or early spring at a depth of one inch (2.5 cm) and 4 inches (10 cm) apart.

Add a layer of mulch around the plants once they become established to keep the roots cool.


Keep sweet peas well watered during hot, dry weather.

It’s best to water the base of the plants and avoid wetting the leaves to prevent mold and mildew.


Sweet pea plants need a support structure for the tendrils to cling onto.

You can use a trellis, teepee, arbor, lattice, wire fence or netting to support the plants.

Set up your support structure before sowing the seeds to avoid damaging the seedlings as they’re growing.

sweet peas growing on a trellis


Sweet peas will appreciate being fed with a high potash fertiliser like tomato food when they begin blooming.

Avoid using a high-nitrogen fertilizer because it will cause the plants to produce lots of leaves but very few flowers.


Sweet peas are excellent cut flowers and their beautiful fragrance will fill your home.

To keep the plants blooming, it’s important to pick the flowers every few days to avoid seed pods forming.

Once the plants go to seed they’ll stop flowering.

The ideal time to pick sweet peas for flower arrangements is when there are at least two unopened flowers at the tip of the stem. 


Sweet pea seedlings will need protection from slugs and snails until they’re established.

Always water the base of the plants to reduce the risk of mold and mildew.


Sweet pea vines will begin to turn brown and die off once the weather heats up in summer.

If you’d like to collect the seeds, leave the seed pods on the plants until they turn brown. 

Collect the seed pods on a dry day and remove the seeds from the pods.

Store the seeds in a paper bag in a dry place for planting the next year.

butterfly on sweet pea flowers


Here are some of the most common questions about growing and caring for sweet peas. If you can’t find the answer here, please add it in the comment section at the end of the article.

How tall do sweet peas grow?

Most varieties grow 5 to 6 feet (1.5 to 1.8m) tall but there are also small bush varieties available that are perfect for containers.

Are sweet peas frost tolerant?

Sweet peas can tolerate cold temperatures and light frosts but they’ll need protection against very cold weather and thick frosts.

Can sweet peas be grown in hanging baskets?

Dwarf sweet pea varieties are perfect for hanging baskets or planters.

So there are my tips for growing and caring for sweet pea flowers.

With the right location and something to climb up, you can expect a stunning display of fragrant flowers during the springtime.


Have you tried growing sweet peas in your flower garden? Let me know in the comments below.

I’d also love to hear if you’ve had success growing sweet peas in hanging baskets.

Are you on Pinterest? I have boards dedicated to Flower Gardens and Garden Ideas that you may enjoy. You can also find me on Facebook.

Kelly Martin

Hi, I'm Kelly Martin, a landscape gardener and designer with over 10 years experience. I have a passion for small space gardening and I love designing and creating beautiful outdoor spaces that maximize the potential of small urban gardens. Read more

This Post Has 2 Comments

  1. Inda

    This is the best and most straightforward advice I’ve read about growing sweet peas.. I’ve also discovered it’s a good idea to cover the sweet pea seeds with loose netting after planting because I saw birds digging up the seeds..
    I’d like your advice about growing Lily of the Valley as well because I just love them but haven’t had much luck..

    1. Kelly Martin

      Thanks Inda, I’m glad you found it helpful. I hope your sweet peas do well this year.

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