When Should You Sow Sweet Pea Seeds

Sweet peas are one of the few annual flowers with enduring appeal and rural charm. They appear to be the exact opposite of our hurried life as they twine languidly around a rustic trellis. Sweet peas are fantastic flowers for gardens and bouquets thanks to their alluring scent. For information on how to plant and care for sweet peas, read our Sweet Pea Growing Guide!

About Sweet Peas

The sour pea Lathyrus odoratus is an annual flower that looks great twining on a trellis or arch, growing in a cutting garden, border garden, or woods. Today, a wide variety of hues, from pearly white to ice cream pastels to ritzy magentas and inky purples, are available for the blooms.

Only their honey and orange blossom fragrance matches their delicate winged flowers. Their appeal has been ensured by the combination of their exquisite aroma and their capacity to generate a large number of flowers for the house over an extended time of cutting.

One of the keys to cultivating sweet peas is to sow them early. Sweet peas are incredibly tough, despite the way they appear fragile. Plant them in very late winter or early spring in USDA Hardiness Zone 7 or colder, as soon as the soil is dry enough to work with. (Don’t plant seeds after the last frost.

When Dr. Robert Uvedale, a teacher from Enfield, Middlesex, received seeds of this exceedingly fragrant annual in 1699 from a Sicilian monk named Francis Cupani, he brought the first sweet peas to Britain. In North America, they gained enormous popularity as garden plants and cut flowers. By the late 1800s, producers in California, especially W. Atlee Burpee, were exporting trainloads of sweet peas across the nation and creating numerous new varieties.

Some people liken the process of producing sweet peas to that of preparing pie dough. Some individuals are gifted, while others are not. This plant sprouts from large, manageable seeds that resemble peas. They are still rather challenging since they take a while to germinate. It’s worthwhile to experiment with various seeds every year.

When to Plant Sweet Peas

  • Sweet peas should be planted as soon as the soil is dry enough to work in very late winter or early spring in most places where frosts occur frequently (Zone 7 and colder). (Start sowing before the last frost! Most certainly, it will be too late.)
  • Plant sweet peas in the late fall (November) if you garden in a region with a mild winter climate (Zones 8, 9, or 10), so they can grow and blossom in the late winter and early spring. Six weeks before you plant the seeds, dig a trench and fill it with compost or well-rotted manure to obtain the greatest show. Sweet peas are gregarious plants that require a lot of nutrient-rich materials to flourish.

Sowing Sweet Peas Indoors

  • Start sweet peas inside in a seed tray to get a head start on the season in the coldest regions of the nation. Sweet peas can withstand light frosts, so plant out as soon as the soil can be worked in early spring, around 6 to 7 weeks before the last date for frost.
  • The seeds’ outer layer is softened and helped to germinate by soaking them overnight. Using a nail file to lightly score the outer shell can also be beneficial.
  • 2 seeds to a module is fine to sow the seeds, but keep in mind that their lengthy roots have a propensity to tangle and can make separation challenging. Sow the seeds around half an inch deep in each cell of a seed tray.
  • Scoop them out gently after they start to sprout their first pea-like leaves and place them in a larger container to harden off. One of the most reputable growers of sweet peas gave me the following piece of advice: “Treat the seedlings like I would treat my husband: put them in an unheated greenhouse, neglect them, and they will thrive.
  • Plant them outside as soon as the soil can be worked.

Sowing Seeds in the Ground

  • Sweet peas thrive when their roots are firmly planted in cold, wet soil and their heads are exposed to sunlight. Plant low-growing annuals in front of them if you can to provide shade for the roots.
  • Pick a spot that drains effectively. If your soil tends to be acidic, it is recommended to add some powdered lime to the surface.
  • Mix liberal amounts of compost or well-rotted manure into the ground to a depth of two feet to create a rich soil. (Learn more about adding amendments to the soil and getting it ready for planting.)
  • You should dig a beautiful, deep “compost trench” that is around 4 inches deep before planting.
  • After digging the trench, use a pencil to cut holes, place the seeds inside, and then press down on the earth to compact it and block out any light.
  • The seeds should be soaked in water for 24 hours prior to sowing. To hasten sprouting, nick the seeds with a nail file before planting. In a temperate climate, seeds don’t need to be soaked.

How to Grow Sweet Peas

  • Depending on the soil temperature, germination after planting can take anywhere from 7 to 15 days.
  • Fill in the trench gradually as the seedlings appear and develop. Hoe additional dirt toward them.
  • Keep the soil wet. Summer rains may be plentiful. Sweet peas can have bud drop; if you stick your finger into the soil bed to its first joint and the soil is dry, water them at the soil level and do so in the morning.
  • You won’t need to fertilize if you plant with a lot of compost and aged manure. Use high potash feeds if you do want to supplement the diet because nitrogen feeds promote excessive top development.
  • Mulch well once plants are planted to keep the soil cool and moist. Unless the soil becomes dry, you might not need to water your sweet peas if you mulch.
  • Pinch off the tops when plants are 6 inches tall, not sooner, as this will promote the production of side shoots too early.

Provide Supports

  • When temperatures rise above 65°F, sweet peas will begin to fade since they like chilly days and nights.
  • Sweet peas are true climbers, with the exception of the bush forms. Provide them with sufficient support for at least 6 feet. Some species can reach heights of nine or ten feet. A braided willow obelisk, bamboo poles in the tee-pee design, or a trellis are examples of other attractive supports. If you don’t have a fence or trellis, give them something to cling on, such chicken wire, bushy twigs, or brush.
  • Give the plants a good start by tying the first few stems to the support; the rest will follow. When they reach a height of 4 to 8 inches, use your thumb and forefinger to pinch out the middle growing point. Plants will grow stronger as a result.

Picking Flowers

  • Pick flowers frequently for bouquets so that the plant will focus its energy on producing additional blooms rather than seeds. Up until the first frosts, the more you pick, the more they produce.
  • Allow a couple of the final blossoms to mature into seedpods when the leaves begin to lose their color. On a windowsill, dry them, and then keep in an envelope in a dry location to sow the following year.

From miniature bedding kinds ideal for pots and borders without support to 8-foot-plus scramblers, there are sweet pea varieties for every setting.

These decorative peas are native to Sicily, where they have flimsy stems and a powerful orange-jasmine-honey aroma. Modern hybrids feature larger blooms and stronger stalks.

However, some of these contemporary kinds, despite having larger blossoms and more fashionable colors, lack the earlier sweet peas’ perfume. Sweet pea ‘Cupani’ is still rightfully well-liked and simple to grow. It has bi-colored flowers with maroon upper petals and violet “wings.”

The decadently fragrant “America” is an antique from 1896. When its petals open, beautiful red and white wavy stripes are revealed.

Look for antiques like the Sicilian “Old Spice” collection. Shades of white, cream, pink, lavender, and purple can be seen in this strain’s blossoms.

A new cultivar with enormous, creamy-yellow blooms with violet shading called “April in Paris” is aromatic.

Although the ordinary sweet pea is an annual, Lathyrus latiflolius, a perennial broad-leaved everlasting pea, is not fragrant. These clambering plants have a height of up to 6 or 7 feet, are hardy to zone 5, require little care, and bloom continuously from year to year.

  • An essential component of a late Victorian garden is the sweet pea. Because of their wide range of colors and aroma, Victorians adored sweet peas.
  • When the dew is still on the flowers in the morning, gather them. Their best aroma is at this time.

Can sweet pea seeds still be started?

Nothing is more pleasant for a gardener than planting sweet pea and other flower seeds in the winter. Getting out my sweet pea seed packets and seeing them germinate and sprout indoors is the most delightful thing to do when there is not much happening in the garden itself and I have been spending days indoors due to the cold, wet weather!

Therefore, if you’ve been considering that the only thing you can do for your garden is sit and observe it from the window, reconsider your position.

Early planting of sweet peas will repay you with delightfully scented and eye-catching blossoms. Sweet pea seeds must be started in late winter or early spring if you plant in a zone 7 or colder climate. Don’t hold off till the last frost! Generally speaking, you should start your seedlings inside 6 to 8 weeks before the final anticipated frost.

It might be too late to grow sweet peas and get decent results if you wait until after your final frost. In other regions of the nation, spring lasts only a few weeks before temperatures suddenly rise. Sweet peas require lower temperatures to grow well.

Before planting, are sweet pea seeds soaked?

  • Sweet peas can be seeded in the fall in warmer places (Zone 7 and above) where the winters are generally not too harsh. Other than that, plant seeds in late winter or early spring. Before planting, give the seeds a 24-hour soak in water. By doing so, the seed coat is softer and the sprouting process is accelerated.
  • Fill your planting containers with high-quality potting soil while the seeds are soaking. Use the deepest pots you can find because sweet peas develop a lot of roots. Ideal containers are 4-inch (10-cm) pots and root trainers.
  • In each container, plant two seeds by pressing a fingertip into the soil and a half-inch (1.25 cm) deep.
  • To boost humidity and hasten germination, cover pots with a plastic dome covering. Place in a warm greenhouse or a house window with good light.
  • Pinch out the center growth tip, just above a leaf joint, once plants are 4 to 6 inches (10 to 15 cm) tall, leaving just two or three leaf nodes. The plant will be encouraged to branch out strongly from the base as a result.
  • Because they use a lot of food, sweet peas need a little more care to produce in large quantities. Apply bone meal, a thick layer of compost or well-rotted manure, and a generous amount of natural fertilizer to planting beds to prepare them. Incorporate these elements thoroughly into the soil.
  • Vines require a sturdy foundation to climb and grow quickly. Affix Hortonova netting or 6-foot (1.8 m) tall metal fence to the tall poles spaced approximately 8 feet (2.4 m) apart down the row for them to climb.
  • Around the time of the final spring frost, plant seedlings outdoors in two rows, one on either side of the trellis, spaced approximately 8 inches (20 cm) apart down the row. It’s crucial to keep the vines bound to their supports as they erupt into lush growth. Sweet peas can grow more than a foot (30.5 cm) per week once the vines begin going.
  • Sweet peas adore water, and they can’t survive without regular watering. Set up soaker hoses as soon as you plant them to prevent their luxuriant development from being restrained. It’s important to maintain their thirst quenched during warm weather. Use diluted fish and seaweed emulsion to feed plants once a week.
  • Pick flowers when there are at least two unopened blooms remaining on the stem for the greatest vase life. To extend the life of the vase, add flower food to the water. It’s crucial to prevent plants from going to seed in order to prolong blooming, so be sure to regularly harvest and deadhead the flowers.

Can sweet pea seeds be planted directly in the ground?

Sweet pea seeds should be directly put into the garden in the fall from September through November in mild winter settings where the ground does not freeze in order to develop robust root systems and blossom in the spring. If you are unable to plant your seeds in the fall, start as soon as spring arrives in a well-drained area that provides some afternoon shade.

In regions with difficult winters, plant about a month before the last date of frost after the worst of the weather has passed. If spring arrives early in your region and becomes hot and muggy, mulch seedlings well and place them where vines will have some afternoon shade.

1. Before planting, you could decide to nick your sweet pea seeds. The seed’s outer layer can be broken off by giving it a quick cut with a nail clipper so it can quickly absorb water. This will result in a higher percentage of your seeds germinating and a few days earlier sprouting.

This is how: Between your thumb and forefinger, hold a seed. Clip your seed by holding the clippers at an angle with the other hand so that you can only utilize the tip of the blade. Not taking a chunk out of the seed is your goal; it is to slice through the brown top layer of the seed. Sometimes the nick you caused is barely visible, and other times a bit of the seed coat cracks off revealing the interior seed’s lighter color. Both are true.

2. Since sweet peas require fertile, well-drained soil, add some aged manure or other finished compost to your garden bed before planting. Work the material into the soil and rake the bed to level it out. Make a furrow with a stick or a tool. Make sure your furrow is 1 inch deep since it’s crucial to plant seeds at the correct depth (for sweet peas, this is 1 inch).

3. When planting your seeds, space them 2-3 inches apart in your furrow. You have a better chance of getting a full bed of plants with no gaps if you sow your sweet peas at this spacing. You will thin your seeds later, when they have grown, to the desired spacing.

4. After sowing, fill in your furrow with earth to cover the seeds. You should only transfer enough soil to fill in the trench without building up a mound above the seeds since you want your seeds to be positioned one depth down.

5. Lightly mist the seeds you covered. To stop the water from washing away the soil, use a watering can or hose with an attachment that diffuses the water so that it showers gently like rain.

Tall sweet peas require a sturdy support in order to ascend. Build one now so that it is there when your seedlings are prepared to begin climbing.

6. You must keep birds, snails, and slugs away from your sweet pea seedlings. In order to prevent these typical predators from discovering your sprouts and eating them before you even realize they are up, you should do this as soon as possible after sowing your seed.

Use netting for birds. Using flexible, black plastic irrigation tubing, often known as polytube and sold at most garden centers, we create our own support hoops. It should be cut into lengths that correspond to the width of your garden beds. To create arches over your sweet pea bed, bury the ends of the cut tubing in the ground. These arches should be covered with bird netting, which should be secured at all edges to prevent openings. Before your sweet peas grow large enough to attach themselves to the netting, remove it.

We choose the product Sluggo for snails and slugs because it is safe for use on people, pets, and wildlife.

7. If you started your seeds indoors, the seedlings must be hardened off before being transplanted into your garden. Hardening off is the process of gradually exposing your plants to the elements they will experience outside, with temperature and direct sunlight being the most important factors. If you don’t, your seedlings can have transplant shock once they are planted in the garden.

When your plants have around 3–4 pairs of leaves, you can begin the hardening off procedure. Place your plants outside where they will receive morning sun in full force and afternoon shade. If you don’t have access to such a place, you will need to relocate your plants every day so that they are in the morning sun and out of the afternoon sun. Move them to a location where they will receive direct sun all day after about 3–4 days. You can move them into your garden in a few more days.

8. We advise deadheading to prolong the blooming period of your sweet pea plants. This entails removing wasted flowers before they have an opportunity to use their energy to produce seeds rather than other blossoms. Deadheading is best done right when the bloom has peaked and is just starting to fade. Cut the entire flower stem off at all times.

9. The blossoming on this plant is completely through. When you can see, the plants begin to slow down and eventually stop flowering altogether as the discarded blooms turn into seedpods. Whether you deadhead or not, all sweet pea plants eventually reach the end of their flowering season. However, you can extend the bloom time by removing spent blossoms.

10. The flowers are, of all, the whole idea of cultivating sweet peas. Remember to cut some and bring them inside; they make lovely, sweet-smelling bouquets. Additionally, the plant will produce more blossoms the more you cut!