6 Easy Tips for growing Sweet Peas
Essential tips for growing sweetly scented sweet peas. Includes how to sow seeds, growing in containers, and picking the right sweet pea variety
Growing sweet peas isn’t difficult but they do need the right soil, care, and support. Very popular in Britain, sweet peas are becoming much more known in other parts of the world as a fragrant flower for bouquets. They’re so much more than that though since they look as lovely in the garden as they smell in a vase. Growing up handmade wigwams or around the front door, their simple and colorful blossoms attract pollinators and smell incredible. Better yet, the more you pick sweet peas, the more they produce flowers. A freshly picked bouquet can last around five days and add instant natural fragrance to your home. By the time the bouquet needs refreshing, many more blossoms will have bloomed and are ready for the next bouquet.
Sweet peas are temperate climate garden flowers. That means that they love warm, but not hot, summer temperatures and plenty of rain. However, rain you can compensate for by regular watering, and warmth can be controlled by some degree by where you plant them. If you’ve not grown sweet peas before, here are six tips to get you started.
1. Choose the right Sweet Pea Varieties
There is a dazzling array of sweet peas available and seed catalogs can be dominated by them! That means that choosing the right type can be both exciting and a little daunting. First of all, sweet peas are not the same as edible garden peas and come in two types — the scented and annual-growing Lathyrus odoratus and the unscented and perennial Lathyrus latifolius. The latter looks very similar to scented sweet peas but literally smells of nothing.
The sweet peas that I grow, and that I’m sure you’re here to learn more about is Lathyrus odoratus. Within that species, there are many types of sweet pea bred for different colored blossoms, style of blossoms, size of blossoms, and growing habit. There are even sweet peas that change color! Each sweet pea group will also have many varieties to choose from. The sweet pea variety is generally the most prominent name on the seed packet and is the name that most gardeners will know it by. The two main groups of sweet pea are:
- Grandiflora sweet peas, also called antique or heirloom sweet peas, typically grow up to seven feet tall. They have shorter stems and a lot more fragrance than modern varieties. Look for ‘Painted Lady’ and ‘Matucana’
- Spencer sweet peas, growing up to ten feet, with long stems, and a wide range of scents. They’re also more heat-tolerant so might be an option if your summers get hot. This is the type most commonly grown for the show bench and popular varieties include ‘Lipstick’ and ‘Windsor’
2. Sowing Sweet Pea Seeds
Sow sweet peas seeds into small pots or modules, rather than directly in the ground. Soak the seeds overnight, and place 1-2 seeds per pot about 1/2″ deep in multipurpose potting mix. Modules will give you more success since you can keep an eye on the seedlings in their early days. Keeping them safe from cold weather, deluge and pests is much easier done when you can lift them out of harm’s way. Sweet peas, like garden peas, will appreciate a deeper growing space since their roots grow deep, relative to their size. Although ordinary modules or pots will do, sowing seeds into deeper root trainers or toilet paper rolls can encourage stronger growth.
Sow sweet pea seeds either in autumn to winter and overwinter the small plants in an unheated greenhouse or cold frame. Many British gardeners (zone 8) sow their seeds in early autumn and leave the plants in the greenhouse all winter long. The mild winter temperatures keep the plants from growing too much, but they begin to shoot up again once it begins to warm.
If you want to start sweet peas during the winter, you’ll need to do it on a heat mat or inside the house. The sown seeds need to be kept around 10-15C (50-60F) in order to germinate. After you see green sprouts, move the modules to a place that’s kept 5-10C (40-50F) both day and night. This slows them down so that they don’t grow too large before spring. You can also wait to sow seeds in spring, but the plants and blooms may take longer to grow.
3. Pinch out the Growing Tips
Sweet pea plants are naturally tall single-stemmed climbers. However, if you pinch off the top growing tip of the plant when it’s young, it encourages side shoots and a thicker and more blossom-abundant plant. It’s a trick that will give you masses of sweet pea flowers and doesn’t hurt the plant at all.
What you do is wait until the plants are about 4-6″ tall. Then with a pair of snips or your fingernails, pinch out the top part of the plant just above the first set of leaves. This stops upward growth temporarily, and the plant will focus on creating side shoots. It’s these new shoots that will continue growing upwards and give you double or more flowers per plant.
4. Grow Sweet Peas in the Garden or Containers
Sweet peas need vertical space to grow but are flexible about where you have them planted. That means that you can plant them in your cottage garden, or plant them into large containers. If you keep a container near the door so that you’re greeted with beautiful scent every time you leave and enter the house. What a great way to begin the day.
Either way, space plants about 8″ apart and into rich soil or potting mix. Soil rich in compost and aged manure encourages lush green growth. Adding a sprinkling of bone meal encourages root growth and potassium-rich feeds and fertilizers encourage bountiful blossoms. Also, ensure that sweet peas are kept well watered or they’ll have a tendency to die back and produce fewer blooms.
5. Growing Sweet Peas on Supports
Sweet peas are fast climbers and given the right conditions, can easily grow six feet tall. What this means is that you should grow sweet peas on supports, and keep tying the plants to the supports every week as they’re growing. Tying them in with pieces of soft garden twine keeps the stems from falling down and breaking. As for supports, I’ve seen gardeners growing sweet peas on ordinary garden pea netting, on lattices, on wigwams, up trellises, and over willow arches. Feel free to get creative with how you grow your sweet peas. You could even use recycled materials to save money and add character to your growing space.
6. Grow Sweet Peas for Cut Flowers
Though of course, sweet peas look incredible clambering up rustic trellises, you need to pick the flowers to keep them producing flowers. If you don’t, then the flowers will set seed and the plants will die back. That’s great news since you can get an ornamental flower and cut flowers in one. They’re honestly my favorite cut flower and I love keeping a bouquet on my bedside table. Waking up to their sweet scent can’t help but put a smile on your face.
To pick sweet pea flowers, use a pair of scissors, and make a cut at the base of each stem. Run your fingers from the flower downwards and make a cut just above where the stem meets the main plant. Gather a handful and make sure to get them in a vase of water as soon as possible. After cutting, the plant puts more effort into creating new flowers since what it really wants is for its flowers to turn into seeds for the next generation. That means that the more you pick, the more flowers you’ll have for both the home and blooming in the garden.
More Flower Growing Ideas for your Garden
To help inspire your garden check out these other flower growing ideas below. They include ideas for growing scented flowers and blossoms for show and to support wildlife
I wanted to have my own sweet peas on my lawn, but I had no idea how to plant them. Thank you for sharing this article! It helps a lot.
Is it ok to pinch the shoots back after they are taller once they stop blooming? Or to cut it back so it is not as tall?
Once the plants stop producing flowers, it’s time to pull them out :) Remember to deadhead sweetpeas after the bloom fades though, since they’ll change into seedpods. Once that happens, the plants will stop producing flowers. Or at least, very many of them.
I started my sweet peas in root trainers in January and by mid-February they were growing roots out from the root trainers. When to start has been a struggle for me. I am in 4a and it is still pretty cold with freezes till May. Any suggestions on when to start them in my area? I feel like I may have started these way too early. After I repotted them … they were more droopy and seemed a lot weaker than before. In the root trainers they look strong and stood straight up. Thanks, MJ
Hi MJ, sweet peas are traditionally started undercover (in a greenhouse/cold-frame) in autumn. They begin growing at that time, then stop for the winter. Once it warms up, they have a head start and begin growing quickly. You can sow the seeds indoors all winter though, but once the sprouts emerge, you need to keep the plants at around 5C (41F) or they’ll grow too fast. You’ve just experienced what happens when you don’t move them to a cooler place after the sprouts emerge — they grow fast, weak, and leggy. My advice would be to give up on this batch and start a new batch of seeds in your root trainers. After you see them germinate, move the plants to a cold, but bright, porch or someplace similar that’s the right temperature.
Wow! This is happening to me right now. I can’t wait to try your advice. Thanks for breaking it down. I knew I was keeping them inside too long!
I have one question: how tall are the sweet peas when you put them outside (after they’ve germinated)? Mine are over 6 inches and are so weak.
Thanks again for the tips! Much appreciated!
ST
It’s far too early to plant sweet peas out here — in Britain (zone 8) the best time is when it warms up in May. When they do go out, they’ll be around 4″ tall, but sometimes a little taller. Not much though since it’s best to nip out the central growing stem to just above the last set of green leaves. The plants will grow bushier for it, and less tall and leggy.
Have been growing these for years and must say they are simply one of the loveliest flowers to grow. The fragrance is wonderful and fills the room where ever they are displayed. My best seeds come from a grower in Sebastapol, California. The old type Spencer varieties with individual colors named and labeled as ordered. Very long stemmed and beautiful colors. The shop is called Enchanting Sweet Peas and I have never been disappointed in any varieties grown from there. I do Spring direct sow planting in my warm Southern USA growing area which works out well for me. Thanks for your interesting and very informative blog and utube channel.
Thank you very much for your instructions! This is my first year to grow flowers and I have watched numerous videos. But, for some reason it was hard for me to understand what the point they are trying to make. None of the videos were explaining the information I needed. But yours did, so again- thank you.
You’re very welcome Beth and good luck with this year’s garden :)
Thank you for the information. This is my first year growing sweet peas. I have them in containers on either side of my front door. I hope they do well! I was happy to find your site. Hope you and your family are safe and well during this time. Happy gardening!
Thank you for this article Tanya, I have just rescued the toilet roll from the rubbish bin. I didn’t know about the pinching out. My sweet peas have just finished flowering so I am hoping to collect the seeds. I have heard that you should swap your seeds with someone else so you don’t grow in the same spot. Is this a old wives tale or not. 🤔
Pretty sure that’s an old wives tale that’s confused with crop rotation. It should be that you grow sweet peas in a different place in the garden each year.
It’s true that sweet peas are one of the most deeply scented garden flowers. I think they are also lovely and attractive. My mother has been planning to plant sweet peas in her garden because of the reasons stated above. She is now looking for seed suppliers in the area. By the way, thanks for providing the tips on how to properly grow them. I will surely share this info to my mother.
How much sun do they like or need?
Our sweet peas get blooms; but the turn black and shrivel up. Why?
They eventually die, shrivel up and turn into seed pods
Love love sweet peas! Good read! I dig a ditch about a foot deep along my fence, put cow or horse manure at bottom of ditch, cover with dirt, and plant my seeds no later than Feb 28th and have beautiful sweet peas early summer to frost!
Great tip Merilyn! Thanks for sharing :)
Sow them each year. Even had some seeds from wild sweet peas,they’re crimson ( they have no scent). I collect the seeds each year. Love them. My favourite I think. They’re so grateful,almost weed-like. This year mine are a bit behind due to starting late bc of moving house and garden.
Thanks for the article. I didn’t know about nipping the shoots.