How To Grow Sweet Peas in Pots: A Guide For Fragrant Flowers

Not every garden has space for a sweet pea patch, but that doesn’t mean you can’t enjoy these lovely blooms. Growing sweet peas in containers is a great way to get all the beauty of sweet peas with a fraction of the effort.

Sweet peas are annual vines that grow well in pots and containers. The plants will reach a mature height of 6-8 feet on a trellis and bloom from spring until the heat of summer. Start the seeds indoors or directly in the container they’ll grow in that’s filled with rich, well-draining soil.

Here’s everything you need to know about how to grow sweet peas in containers, including the best varieties to plant and the secrets to getting loads of flowers.

Why grow sweet peas in containers and pots?

There are several reasons to grow sweet peas in pots that go beyond simply saving space (although that’s an important reason!)

• If you don’t have a lot of space, sweet peas are an excellent option for filling a small area with color and fragrance.
• You can control the soil quality more efficiently when the plants are in pots. Soil quality is paramount because sweet peas need well-drained, nutrient-rich soil to thrive.
• You can move the pots around to get the best exposure for the plants. Full sun is ideal, but they will also do well in partial shade.
• Even in-ground gardens look beautiful with containers of flowers scattered throughout.

How to help sweet peas thrive in pots and containers

Sweet peas are tolerant plants, but you can do a few things to ensure they have the best chance of success in containers.

Pot size

Use a large pot, preferably at least 12-inches wide and equally as deep. Sweet peas have an extensive root system, so they need a pot to accommodate their growth. A too small container will limit the plant’s root development and result in smaller blooms.

Ensure the pot has suitable drainage holes in the bottom to avoid soggy soil. If you’re using store-bought containers, this should already be taken care of for you. If you’re upcycling an old bucket or another planter, drill four or five half-inch holes in the container for drainage. 

A larger pot will also help moderate soil temperature better than a smaller one. Since sweet peas prefer to have cool soil, keeping a low, steady soil temperature will help prevent the heat from affecting their bloom production as much as it otherwise could.

Growing your sweet peas in hanging baskets is another option if you want to take advantage of every inch of your outdoor space.

Soil for potted sweet peas

Sweet pea plants are heavy feeders. They have a lot of growing to do, and just a short time to do it, so they need plenty of nutrition.

Create a planting mix that is half potting soil and half compost. This mix will provide enough nutrition to get the plants off to a good start and sustain them for their months-long blooming period. A top dressing of more compost or aged manure at the 6-week mark will keep them fed and growing strong.

You can also use any other type of organic plant food, especially one that is high in phosphorous, the nutrient responsible for flower bud development.

Here are a few ideas to get you started:

Sunlight and water requirements

Even though sweet peas grow best in the cool spring weather, they thrive in full sun, though they can tolerate some shade. One of the convenient things about growing sweet peas in pots is that you can move them around to get the best exposure for the plants regardless of where the rest of your garden is.

Sweet peas are typical in their water needs, requiring about an inch of water each week. Spring rains may provide all the water they need depending on where you place the containers. Check the soil before watering to avoid over or underwatering the plants.

If you need to supplement with irrigation, water plants in the morning to avoid getting the foliage wet and allow them to hydrate before the day warms up. Consistent soil moisture is critical for growing sweet peas. They will suffer from bud drop if the soil becomes too dry or overly wet.

Water temperature can also affect sweet pea blooms, which was something new I learned this year and wrote about it in this article: Sweet Peas Not Growing Well? Here’s How To Fix It. Let my research help you have the best sweet pea blooms!

Sweet pea companion plants

Since sweet peas grow best with their heads in the sun and feet in the shade, they will need either a layer of mulch or companions in the pot. Some common mulches that are also easy to find are wood chips, grass clippings, leaves, or even pea gravel. All will help to keep the soil cool and out of the sun.

Living companions in the pot are easy to select, too. Sweet pea plants create a tall vine; any low-growing or spilling plant will help keep the soil cool and make the pot more attractive.

Petunias, dwarf marigolds, calendula, and alyssum are a few good choices, but you can get more ideas in this article, 11 Flowers And Vegetables To Plant With Your Sweet Peas.

You can also pair sweet peas with another flowering vine, as long as there’s enough trellis space to go around.

Choose companion plants with the same soil, sun, and food needs as the sweet pea, so each plant has its needs met.

When to start sweet peas in pots

Sweet peas are one of the few flowers that do best when planted in the winter. They are in the family of cool-season crops, and if you wait until after the last frost in spring to plant these fragrant beauties, by the time the plants mature enough to bloom, the hot summer weather will shorten their blooming period significantly.

Direct sowing

For USDA growing zones 7 and under, plant seeds directly outdoors into a pot of potting soil and compost mix (50-50 mix) in late winter. Leave the pot outside to sprout and grow. This method avoids any need to harden off the seedlings or transplant them, so it’s perfect for minimal effort.

Indoor sowing

Alternatively, you can start sweet pea seeds indoors eight weeks before your last frost date. Allow the seeds to grow for six weeks indoors, then transplant the seedlings into their permanent containers outdoors two weeks before spring begins in your area. Don’t forget to harden off your seedling and avoid transplant shock.

A trick to speed up germination is to soak the seeds overnight to soften the hard outer shell. You can also knick the outside with the tip of a knife to help the water get inside the seed shell. This step can shave a few days off the germination time, but it isn’t required in order to have success with sweet peas.

Fall sowing

If you live in a USDA growing zone of 8 or above with more mild winter weather, try sowing your sweet peas in late fall. Planting in late fall will give the seeds plenty of time to sprout and establish themselves in the cool weather. The plants will grow very slowly, if at all, through the winter months but will burst into growth in the spring.

Since the soil will already be moist from fall rains, you don’t need to bother soaking or knicking the seeds with fall sowing. Another advantage of fall sowing is that it will provide you with the longest blooming period since you’re giving the sweet peas a head start on growth in the fall.

How to plant sweet peas in pots

Sowing sweet peas in pots is straightforward and shouldn’t take long at all.

Once your containers are filled with potting soil, poke a small hole for each seed about 1/2 inch deep.

Drop one seed into the hole and cover it with soil. Firm the soil down gently and water thoroughly. The seeds need total darkness to germinate, so covering them is critical for strong germination.

Plant 4-6 seeds per 12-inch pot to ensure you have enough sweet pea plants, even if some seeds don’t germinate. Keep the soil moist at all times, and you should see sprouts popping up in 7-14 days.

For a more thorough description of how to start seeds indoors, jump over to this article for all the details: Step-By-Step Guide To Starting Seeds Indoors (Plus a sample setup).

Best sweet pea varieties to plant in pots

Most sweet pea varieties will perform just as well in containers as in the ground, as long as you provide a trellis for them to climb. If you’re truly limited on space, try a hanging basket with dwarf varieties. This setup will eliminate the need for a trellis, and it will move the pot off the ground and into vertical space, saving you a little more room for other plants.

Most fragrant:

• Royal Mix is a highly fragrant mix with a color for everyone, with blooms in red, purple, white, pink, and mauve.
• Matucana sweet pea has won awards for its outstanding fragrance. Bi-colored purple and maroon blooms are large and make excellent cut flowers. I have a packet of seeds ready for this fall’s sowing.

Dwarf:

• Sugar and Spice is perfect for standard pots or hanging baskets. These pink and red flowers stay compact at less than 10 inches tall and wide.
• Knee High Mixture: Get all the color variation in this semi-dwarf variety. The traditional pink, purple, white, and burgundy mix to make a gorgeous hanging basket or pot.

Standard:

• America was my sweet pea variety of choice this year. Tall, vigorous vines covered my chicken wire trellis, and the red and white streaked flowers smelled delicious.
• Early Multiflora is a vigorous climbing sweet pea that produces large clusters of fragrant blooms. The multi-colored flowers make an ideal cut flower that will fill your home with spring beauty.

Tips for thriving sweet peas

• To encourage the plant to develop more lateral growth, pinch the tops of your sweet pea plants when they’re 6-inches tall. The plants will be bushier and produce more flowering stems after they’re pinched back.

• Sweet pea plants will need a support system to keep them growing upright. A trellis, arbor, teepee, or porch post is ideal for potted sweet peas. Loosely tie the first few stems to the support to give them a good climbing start, then the stem will twine its way around the support on its own.

• Cut flowers for bouquets often, and the plant will put energy into developing more blooms instead of producing seeds. The more flowers you cut, the more the plants will grow until the first frost of fall. Deadheading any spent flowers on the vines will also help keep production high.

• Cut the flowers early in the morning for the strongest fragrance.

• You can harvest sweet pea seeds for next year by allowing the last few flowers to form seedpods. Harvest and dry the seedpods on a sunny window sill.

Learn more

Here are a couple more sweet peaarticles to cover all your bases:

• Should I Trellis Sweet Peas? Tips For Success
• Sweet Peas Not Growing Well? Here’s How To Fix It