As soon as the sweet peas’ brittle, brown shells appear, start preserving the seeds. Sweet pea seedpods won’t germinate if you harvest them before they are fully developed. However, if you wait too long, the fragile seed pods will crack open and scatter their seeds all over the place. The procedure may take a few weeks, so keep an eye on them. You need to immediately pluck the pods if they start to split.
Sweet pea seeds are simple to collect. Remove the seeds from the seedpods and bring the plant inside. The seeds should dry for about three days on a level surface, such as a countertop or baking sheet, lined with newspaper. Once they are dry, store them to maintain their dryness in a freezer bag or Mason jar with a tight-fitting lid. Before planting, keep them in a cool location.
Do sweet peas reproduce on their own?
Although sweet peas can be grown in pots or hanging baskets, a larger in-ground growing area is typically preferable. These plants want lots of space both in breadth and depth because the size of the blossoms is inversely proportional to the size of the roots.
It is advised to use containers that are at least 18 inches deep because lesser sizes can stunt growth. Use smaller containers if you don’t care about this. In either case, the blossoms are lovely. Just make sure to water them regularly to prevent drying out.
Look for sweet pea seeds that are advertised as being suitable for container growth.
In a warmer climate, yes. It is definitely feasible for some sweet pea plants to self-seed the next year if you allow them to go to seed in the fall and let the seed pods burst open and release the seeds. This is known to occur in zones 7 or warmer. If the seed does not freeze throughout the winter, it might also occur in regions with lower temperatures.
With pinching back (selectively removing the tips of major stems) and deadheading (removing dead blooms and their stalks), sweet peas will grow more profusely, although it’s completely optional.
At the time of planting, install the trellis or arch. Make sure the plants are getting hold of the supports and nicely covering the trellis by checking on them every few days.
Yes. Pods will develop once the blooms have finished blooming. These pods will contain seedlings. When they are brown and dried and the pods are just beginning to open, they are suitable for harvesting.
Yes. The secret is to select sweet peas when the blossoms at the stem’s top are still closed. Make a precise incision through the stem. Put the freshly cut flower right into a vase filled with room temperature water and cut flower preserver. In a vase, they typically last for 4 to 5 days.
Can sweet peas be grown from seed?
Sweet peas should be planted in a well-drained but moisture-retentive soil in an open, sunny location. Sweet peas are ideal for container gardening. utilize a compost that is good, peat-free, and has a slow-release fertilizer added in.
How to sow sweet peas
From seeds, sweet peas are simple to grow in the spring or autumn. If you are planting in the fall, make sure you have space for them to grow until spring in a frost-free location.
Sweet pea seeds sprout fairly quickly. However, by nicking the seed coat with a knife and avoiding the “eye” region, you can encourage germination. Either plant seed in trays, root trainers, or 9cm pots (3 to a pot). Place the seed in a cold frame or greenhouse after sowing it in high-quality, peat-free compost.
View Monty Don’s instructional video on how to cultivate sweet peas from seed:
Planting out sweet peas
Once all risk of frost has passed, you can start planting your sweet peas in late May. Put them outside throughout the day and bring them inside at night to harden them off before planting. When young sweet pea plants are around 10 cm tall, pinch out the tips to promote bushy growth.
In the spring, you can purchase sweet pea plug plants. Under a support, such as a wigwam made of bamboo canes, plant them in rich soil. The average sweet pea will reach a height of 2 meters. Until they have a healthy growth, water them well. Don’t worry about separating individual plants; simply space sweet pea plugs or pots about 20 cm apart.
Watch Monty as he demonstrates how to put out store-bought plants while planting sweet peas. Find out the advantages of giving them a nice drink after planting as well as why it is best to plant them out just once the soil has warmed up:
Choosing sweet peas and perennial peas
The major consideration is whether or not aroma is crucial to you when deciding between perennial Lathyrus and sweet peas. Decide if you would then like an annual or perennial plant. There are several color choices available as well as climbing and bushier varieties.
Fragrance
Choose sweet peas (Lathyrus odoratus), which are generally very fragrant, if you enjoy a pleasant garden and sweet-smelling flowers for indoor use.
Lord Anson’s blue pea (Lathyrus nervosus), a perennial Lathyus, is an exception to the rule since it does have a perfume.
How long the plant lasts
After setting seed, sweet peas (Lathyrus odoratus) only have a one-year lifespan. However, don’t let this deter you because they are quite simple to grow from seed. Lathyrus latifolius is an example of a perennial species that returns every year, however there are fewer options and they typically lack smell.
Colour
The annual sweet pea (Lathyrus odoratus) has a large variety of blossom colors, including bicolored varieties. However, the perennial varieties do come in some uncommon colors, like yellow and orange.
Habit
The majority of Lathyrus are climbing plants, therefore support them with canes, netting, or allow them to climb over a bank or through a bush. For ground cover and pots, clumping varieties like the spring-flowering Lathyrus vernus and dwarf bushy sweet pea varieties like “Snoopea” and “Bijou Mixed” are excellent choices.
Buying sweet peas and perennial peas
Although many garden centers also sell a few sweet pea seeds in packets, the largest assortment of sweet pea seeds may be acquired from internet seed suppliers. In the spring, several nurseries and garden centers sell pots of germinated sweet pea seedlings that can be divided into individual plants and raised in pots before being planted outside.
There are a few seed specialists who sell perennial Lathyrus seeds, like Lathyrus latifolius, but many gardeners opt to purchase the plants instead. The plant you’re looking for can be found using our Find a Plant tool.
When to plant sweet peas and perennial peas
- Annual sweet peas should be sown either in late January or early April and planted out in April.
- Sow perennial Lathyrus in the spring or the fall.
Where to plant sweet peas and perennial peas
Locate a sunny area where there is room for the plant to grow or to bush out (depending on its habit). Also acceptable is a little light shade, especially for Lathyrus grandiflorus.
How to plant sweet peas and perennial peas
- To avoid cold shock, indoor seedlings should be hardened off for 10–14 days before being transplanted outside.
- Ideally, four weeks before planting, enhance the soil by incorporating a soil conditioner like garden compost or manure.
- Sprinkle general-purpose fertilizer, as directed on the pack, into the area where you plan to plant it, such as Growmore, Vitax Q4, or blood, fish, and bones.
- Before planting, water your plants thoroughly to hydrate the roots.
- Remove pots from larger plants and ease seedlings out of modules or pots while being careful not to snap or crush the stems.
- Plants should be separated by 20–30 cm (8–1 ft).
- Place climbing plants near to their intended support (within 5-7.5cm or 2-3in), with two plants at the foot of each cane if they are climbing a wigwam.
- After planting, water once more to help the soil surrounding the roots settle.
Use garden twine or sweet pea support rings to secure young climbing plant shoots to canes, pea sticks, netting, trellis, or shrub shoots that they will be growing up. Tendrils in contact with supports will naturally start to cling on, but if any are straying or in danger of snapping, keep tying in new shoots.
In dry weather, check on plants in the ground every 3 to 4 days and on those in containers every day because they won’t flower as well if they become too dry. Each time you water, be sure to use enough water to completely moisten the roots.
Apply a high potassium liquid fertilizer, such as tomato feed, once or twice a week on light or infertile soils. This promotes flowering, particularly in annual sweet peas (Lathyrus odoratus).
Pick or remove dead flower heads as frequently as you can once flowering starts. For annual sweet peas (Lathyrus odoratus), which will stop flowering if seedpods are allowed to form, this is especially crucial.
Pinching out
When plants are around 7.5 to 10 cm tall, pinch out the shoot tips of new spring-sown sweet peas for gardening (3-4in). This promotes robust side branching. Autumn-planted seedlings frequently naturally branch.
Cordons
Pick the strongest shoot and keep pinching out all the tendrils and other sideshoots as they grow whether you want to enter your sweet peas in a local show or just want to maximize the size of blossoms for cutting. By using this technique, the plant directs its attention to the blossoms. The term “cordons” is used to describe these single-stemmed plants.
One stem per bamboo cane or tall stake needs to be tied to them on a regular basis. To keep the shoot in place as it grows, you can use twine looped in a figure-eight pattern around the cane and stem. Use sweet pea rings, which are wire loops that wrap around the stem and cane and are lightly squeezed until they hold, to make things simpler.
Cordons have the potential to grow much taller than the typical 2 m (6 1/2 ft) estimated height.
Cutting back
Cut perennial Lathyrus back to the ground in the fall, or better still, wait until February to do it so the dead stems can serve as wintertime cover for wildlife. When flowering is ended at the end of the summer, annual sweet peas can simply be pulled out and composted. This might happen a little bit sooner during hot, dry seasons.
Methods
Sweet peas can be immediately sown into the ground in April, or they can be planted in seed compost pots in the fall or spring. Although it takes more time, pot-sowing is typically more dependable than direct sowing. If you plant in the fall to enhance your chances of getting early blooms, keep seedlings in a coldframe or cold greenhouse over the winter to protect them from growing lanky. Keep the coldframe’s lid elevated unless a strong frost is anticipated. Sweet peas planted in the spring flower in 12–14 weeks.
Sweet pea seeds frequently have a tough outer covering that makes them more challenging to germinate. Place your seeds on a layer of damp vermiculite or kitchen tissue and store them in an airtight container in a warm area. As soon as the seeds swell or start to sprout, plant them. Some gardeners like to soak the seeds overnight instead, but if you don’t plant them right away thereafter, they might rot. With a sharp penknife, chip off a little portion of the hard seed coat to allow moisture to enter and promote germination on recalcitrant seeds that haven’t swelled.
- Individually sow seeds in seed compost-filled rootrainers or 9 cm (3 in) pots. As an alternative, sow five to seven seeds per 13 cm (5 in) pot, spacing them 2-3 cm (3/4-11/4 in) apart.
- Add 1 cm (1/2 in) of vermiculite or compost to the top of the seeds.
- Add water and maintain at around 15C. (59F)
- It is optional to cover the pots with clear polythene or glass to reduce the likelihood that they will dry out, but keep in mind to remove the covering after the seeds have germinated.
- Once they have grown to around 3.5 cm (11/2 in), carefully transplant single seedlings into 9cm (3 in) pots if you have seeded them several to a pot.
- Use your thumb and finger to pinch out (remove) the top of the shoot just above a healthy leaf when the seedlings are 7.5–10cm (3–4in) tall. This will promote side branches, which are always stronger than the core stem that has been removed.
- At least four weeks before planting, remove all weeds from the soil and add a soil enhancer, such as garden compost, manure, or composted bark.
- Only plant seeds as the soil begins to warm, typically around April.
- To create a wigwam, plant any temporary supports, like pea sticks or bamboo canes, in the ground.
- Take out a shallow drill of dirt 2.5 cm (1 in) deep for rows of sweet peas, and plant a seed every 5 to 7.5 cm in it (2-3in)
- Seedlings should eventually be spaced 20–30 cm (8–1 ft) apart to provide the plants enough room to flourish. The extra seedlings may seem like a waste to compost, but unless treated carefully, their roots are typically too damaged to recover.
- Push two seeds into the ground at the base of each cane to a depth of 2.5 cm (1 in) when sowing around a wigwam of canes.
Perennial peas
In the spring or the fall, divide bigger plants. If you want to divide Lathyrus vernus in the spring, wait until after flowering.
Unfortunately, very few of the issues with sweet peas and perennial peas are extremely problematic.
- Powdery mildew, which is brought on by drought or insufficient hydration, results in a grey leaf coating.