How to Grow Sweet Peas – An Easy Beginner’s Guide
Sweet peas are elegant, beautiful flowers that bloom early and provide a dreamy display of pinks, reds, purples, and whites. These fragrant flowers are well-loved for their sweet scent, vertical interest, and romantic look. Whether they’re in a vase or teeming up a trellis, I adore having these plants to enjoy, especially early in the season before many of my other flowers have bloomed. In this simple guide for how to grow sweet peas, I’ll share my top tips for maximizing your blooms and a step-by-step guide to growing.
Why Grow Sweet Peas?
Sweet peas may not be the easiest flower to grow, but they’re entirely worth it! And once you know a few important tips about growing sweet pea plants (like the best temperatures for growing and how to support their long stems!), you will not regret adding them to your flower garden!
Here are just a few reasons to love these exquisite flowers:
- Vertical profile. Sweet peas love to climb and can grow up to 10′ tall! Their long vines create an enchanting feel whether you grow them on a trellis or climbing frame, cattle panel, or flower netting stretched between some t-posts.
- Delicate petals. Sweet peas are delicate, whimsical flowers. Their ruffled petals and variety of shades gives them an ethereal look that’s just gorgeous in the garden or in a vase. There’s truly nothing like a wall of tall-growing sweet peas!
- Intoxicating scent. After smelling fragrant sweet peas for the first time, I just had to grow some myself! Their sweet, fresh scent is reminiscent of citrus or fruit. As a flower lover, I adore having their delicious scent wafting through the garden throughout their growing season.
When to Start Your Sweet Peas
One of the most important things to know about sweet peas is that they love cool weather! It’s a common mistake to wait too long to plant, and sweet peas just cannot tolerate the heat like other flowers can. They prefer the cooler temperatures of the springtime and early summer.
Sweet peas can handle colder temperatures well (even into the 20s!), which means that they need to be planted very early in the year. You do not have to wait until the last spring frost is over to start!
For warmer regions, they can even be planted in the late winter. Early spring is best for colder climates.
Sweet peas seeds can be direct sown or started in containers.
When to plant by zone
- For zones 7 and up: In these warmer zones, sweet peas do well if they’re planted in the fall and overwintered.
- For zones 5-7: You can start your seeds indoors as early as January/February, or direct sow around early April.
- For zones 5 and below: You can plant indoors around February/March and transplant outside once the ground is no longer frozen.
What Are the Best Conditions for Growing Sweet Peas?
Sweet peas love cool temperatures, well-drained soil, and plenty of nutrients. In the springtime, they thrive in full sun, but may need some shade in warm weather.
They are hungry plants and prefer lots of compost or other organic materials. You may consider planting them in raised beds if your soil is too wet in the springtime.
Sweet peas also need support from a trellis, flower netting, or fencing.
Step-by-Step Guide to Growing Sweet Peas
Alright, let’s jump in to getting your sweet peas planted!
Should you direct sow or transplant sweet peas?
You can either direct sow your seeds or transplant sweet pea seedlings.
The benefit of transplanting is that you can get a head start on the growing season, and you can have more control over your seedlings.
The downside of planting your sweet pea seeds indoors is that their roots can be quite sensitive, so you have to be extremely gentle and use caution when you transplant them. In addition, they grow very long roots and need a deep container so they have plenty of room to stretch and grow. Deep pots or trays of at least 4″ is best. Root trainers are another good option for letting them stretch their long roots.
Tip: Don’t let your sweet peas get too warm. They prefer cooler temperatures of 50-55°F to germinate. If your house is too warm, you might consider germinating them in a cold frame or unheated greenhouse. Too much heat can leave you with leggy plants and otherwise unhappy sweet peas.
Regardless of whether you transplant or direct sow, it can be helpful to soak your seeds for 24 hours prior to sowing. This will soften the seed coat and improve germination success.
Spacing
When temperatures are consistently above 20°F, you can direct sow or transplant your young plants outside. Of course, make sure you harden them off before planting.
Plant sweet peas about 4-6″ apart in well-drained soil with plenty of sun.
Planting your sweet peas
Sweet pea vines can grow up to 10′ tall and need some kind of support to climb on. A trellis, cattle panel, or flower netting can work well.
Sweet peas are heavy feeders and need plenty of nutrients as well as water. Before planting, make sure your soil is rich with compost, such as fish emulsion, manure, or other organic materials.
Adding fertilizer around the base of the plant regularly (about once a week) while they’re establishing also helps to keep them happy.
Caring for your plants
As your sweet peas grow, be sure to water them regularly and deeply. A drip irrigation system can be a good idea for making sure your sweet peas don’t get too thirsty. They are vigorous plants, and once they get established, they will take off and keep climbing!
Deadhead any spent flowers every few days.
Tips for harvesting
- Sweet peas make gorgeous cut flowers and can last for 3-5 days in a vase. To help them stay beautiful as long as possible, harvest the flowers when they’re only partially opened.
- Depending on the look you want, you can harvest either just the stem and bloom, or more of the vine for a more natural, carefree look.
- Sweet peas are sensitive to ethylene. Keep them away from any ripening apples, bananas, melons, and avocados that may be on your kitchen counters.
Favorite Sweet Pea Varieties
You can buy annual or perennial sweet pea seeds. While perennials have the obvious benefit of coming back for more than one year, they tend to lack the sweet fragrance that annuals have.
You can also find sweet pea dwarf varieties that are perfect for window growing or small gardens. Many gardeners have good success growing dwarf sweet pea varieties (such as ‘Little Sweetheart’) in containers as they don’t require support.
I get my sweet pea seeds from my friend Emilie of The Flower People. She has good quality seeds and over a dozen different varieties! Check out all her sweet pea options here, and good luck growing!
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