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!
How deeply should sweet peas be planted?
To make a deep, narrow root run, some gardeners sow their seeds in toilet paper rolls.
Sweet peas are really simple to grow from seed. In the fall, you can sow them into compost pots and grow the young plants through the winter in a cold frame or chilly greenhouse. Alternatively, you can wait until spring to plant seeds in the ground or in pots.
The seeds should be prepared by leaving them on wet paper towels until they expand or sprout. The kitchen roll should be laid out in a sealed container and kept in a warm area. Although it expedites the process, moist soil will still allow your seeds to germinate successfully. In a pot, scatter a number of sweet pea seeds using high-quality compost. They should be buried about 1 cm deep, covered with compost, and well-watered.
Choose a tall container to give your sweet peas a strong start because they perform best when their roots are made to grow in a deep, narrow channel.
Is it necessary to soak sweet peas before planting?
- 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.
How are sweet peas grown from seeds?
One of the simplest flowering annuals to grow from seed is the sweet pea. In the garden, sweet peas are frequently direct-seeded. Give them a location with full to partial sun and rich, loamy soil that is deep, wet, and well-drained. To improve the soil and make it more friable, add lots of organic matter (compost, well-rotted manure, leaf mold, or humus).
When they are planted at times with colder temperatures, sweet peas thrive. The “season” for cultivating sweet peas is different depending on the location. To enhance winter and spring blossoming in western North America, sweet pea seeds should be sown from August forward. Although harsh freezes can cause sweet peas to die back, the plants can withstand frost without suffering too much damage. In the west, sweet pea blooms can be enjoyed well into the summer because of cooler nighttime temperatures.
Sweet peas can be started inside early for transplanting or planted right away once the worst of the weather has passed in the drier plains regions. Sweet peas have been successfully cultivated in Colorado’s hot summers by cut flower producers who mulch thickly as the plants mature and the temperature rises.
In the south, plant seeds in November or December for fresh cut flowers in early spring. In the non-coastal mid-west and northeast, start seeds indoors in February and transplant them outside after the ground thaws. In April, seeds can also be planted directly into prepared garden soil. The northeast’s coastline regions are also great places to raise sweet peas for the spring.
For sweet peas to bloom magnificently in your yard, you will need about 50 days of chilly temperatures (below 60 F). The seed coat of the sweet pea is tough and insoluble in water. There is no proof that sweet pea soaking will promote germination. A sweet pea seed’s outer layer can be punctured to allow for quick hydration, which speeds up and increases germination. The sweet pea seed coat can be easily nicked by scoring it with a nail cutter. When the soil is between 13 and 18 C or 55 to 65 F, sweet pea seeds will begin to sprout.
In holes that are about two inches (two knuckles) deep, plant seeds. Fill each hole with two to four seeds, and spacing them four to six inches apart. Till seeds have sprouted, thoroughly water and maintain soil moisture. Germination should occur within 10 to 21 days. Water the seedlings frequently once they start to grow to encourage robust, wholesome growth. Thin out the seedlings when they are three to four inches tall, spacing the strongest-looking plants four to six inches apart. You can enjoy your sweet peas for a longer period of time by sowing seeds once a week throughout a number of weeks.
Grow them in four-inch plastic or peat pots filled with a seed-starting mixture devoid of soil. Put two or three seeds into each container, each one being pushed an inch into the potting soil. Put the pots in a cool, dark location after covering with mix and water. Watch for new shoots to appear above the earth after about 10 days. Bring the plants outside into the sunlight at that stage. Keep them cool (below 55°F); if you keep them in a heated room, they won’t be hardy enough to move outside without a lot of time to harden off. Reduce the seedlings to one plant per pot until they have two sets of true leaves. As soon as the soil is workable, transplant into the garden about a month before the last date of frost because the shoots are hardy and won’t be affected by light frost. 12 inches should separate dwarf bushy forms, and 6 inches should separate climbing variety.
To avoid harming the roots, it is advisable to plant the stake or support with the seed or transplants when planting tall, long vine sweet peas. Although trellises are the most typical supports, there are various ways to climb. Sweet peas may climb on bird netting strung between two stakes, twine, string, or fishing line hung from the top of a split rail fence, a bamboo teepee, and brush stakes. If the support isn’t up against a wall, scatter seeds all around it to create a stunning display of blossoms that are visible from all angles. A four to six-inch layer of organic mulch will keep the roots cool and lengthen the growing season once the plants have been thinned out.
Avoid overfertilizing to avoid producing lots of very deep green foliage but few blooms. For the initial plant development, a 20-20-20 slow release fertilizer combination that is balanced works well. As an alternative, sweet peas benefit greatly from organic fertilizers. Composted manure mulching will help keep the soil moist and supply nutrients for healthy plant growth and blossoming.
When flowers start to fade, deadhead the plant if blooms are not frequently pruned. The plant will produce fewer flowers overall if seedpods are allowed to develop. More flowers will result from removing spent blooms.
Similar to other direct-sown seeds, the first difficulty for sweet peas is avoiding being devoured by rapacious birds, mice, squirrels, and other animals. Sweet pea seedlings are particularly susceptible to bird, slug, and snail damage if planted in the fall in a warm area.
Preventative actions frequently stop a problem in its tracks before it really has a chance to begin. For healthier plants, abide by these recommendations. Sweet peas should be planted in a region with sufficient airflow. Wet leaves are a magnet for fungus, so water early in the day so they are dry by dusk. Consider sweet peas as a type of food crop. Planting locations should be rotated so that sweet peas are only cultivated in one location every four years. Do not plant sweet peas where other legumes are flourishing or were previously planted. Garden peas, all varieties of beans, peanuts, and clover are examples of legumes.
In particular, certain specialized nurseries or garden centers may sell sweet pea plants. There might be sweet pea plantings in ready-made containers, creating an instant garden. When buying sweet peas, search for plants in individual peat or earth-friendly pots as they require special care when transferred. The better, the bigger the pot. Snip off any blooms or flower buds just before planting. Now is the moment to establish the roots thoroughly so they can support the needs of the developing plant. You will gain larger plants with a profusion of bigger flowers even though you give up early blossoms.
Plant in a pot or in garden soil that has been prepared. To protect the priceless roots from damage when transplanting, it is even more crucial to place the support first. Attempt to maintain the root ball’s unity. It should be planted at the same depth as when it was first emerging. Water it after gently firming the dirt around it. A week to 10 days should pass before mulching. Till the plants are well-established, make sure to maintain the mulch at least an inch away from the stem of the plant. Otherwise, you run the risk of suffocating the stem or potentially fostering bugs, illnesses, and insects.
Sweet peas entered the world of containers when “Cupid,” the first dwarf sweet pea, was introduced at the turn of the 19th century. Their small size makes them ideal for use in pots, urns, hanging baskets, window boxes, and other types of containers. Numerous varieties of dwarf sweet peas are offered in store-bought seed packets or through mail-order catalogs.
Sweet peas that climb are excellent container plants as well. Instead of placing one or two seeds in the center of the pot, place a circle of seeds an inch inside the rim of the pot, spaced a few inches apart. It is simplest to plant the support first, then scatter the seeds around it, in the constrained space of a container. Tomato cages make excellent supports for larger containers; the legs can be pressed into the potting soil. You can put a container of sweet peas in the garden in the early spring because sweet pea shoots aren’t affected by frost (at the same time youd plant seeds outside.)
Start trimming flowering stems for indoor bouquets when the first blooms show. You’re encouraging the plant to produce more flowers in addition to enhancing the lovely scent in the home. Every other day, during the morning hours when they are freshest, trim the stems. For climbing kinds, trimming lateral shoots that emerge from the base of the leaves will slow vegetative development, boost flower production, and improve airflow around the plant.
When you first arrange the stems, they will appear full. As the early blooms fade, the remaining buds will open. Make sure to get rid of any leaves in the vase that are submerged in water. If the base of each stem is trimmed off by 1/4 to 1/2 inch, a bouquet of sweet peas will easily last a week indoors. The water should also be changed every day.
The National Garden Bureau provided permission for this information to be republished. The person who wrote this fact sheet is Cathy Wilkinson Barash. Renee’s Garden provided the sweet pea image “Pastel Sunset,” while Bodger Seeds Ltd. provided the sweet pea images “Ocean Foam” and “Streamers Mix.”