As annual plants, sweet peas (Lathryus odoratus) complete their whole life cycle in a single growing season. This traditional flower germinates well in cool environments, but if the plants are not covered, frost and freezing temperatures can cause damage to sweet peas. Direct sow sweet peas outdoors in late fall in warmer areas to enhance winter and spring blooms. Young seedlings can survive cold snaps if they are shielded from abnormally low temperatures.
Tip
Sweet peas can withstand a slight frost, but immature seedlings can freeze in temperatures below 25 degrees Fahrenheit. To ensure your cutting garden flowers will endure chilly nights in the early spring, protect sweet peas when low temperatures are anticipated.
Do peas need to be covered for frost?
Peas can survive in temperatures as low as 28 degrees Fahrenheit (-2 C.) Peas and pea seedlings will be fine as long as temperatures don’t drop below this level.
Peas can withstand the cold in temperatures between 20 and 28 degrees F (-2 to -6 C), although they will experience some harm. (This is presuming that there is no insulating layer of snow when the cold strikes.)
If snow has fallen and has covered the peas, the plants can tolerate temperatures as low as 10 degrees F. (-15 C.) or even 5 degrees F. (-12 C.) without suffering too much damage.
The ideal temperature range for pea growth is between 50 and 70 degrees Fahrenheit (10 and 10 degrees Celsius) throughout the day and night, respectively. But even outside of these ranges, peas can still develop and bear fruit because these are the ideal conditions for their growth.
Folklore might suggest that you plant your peas by the middle of March, but it is always a good idea to consider your region’s climate and weather patterns before doing so.
The lowest temperature that sweet peas can withstand is what?
According to Gardeners’ World (opens in new tab), sweet peas should be treated like any other non-hardy annual: “Plant your sweet peas outside starting in late May, after all danger of frost has passed. Put them outside throughout the day and bring them inside at night to harden them off before planting.
The most recent edition of Sarah Raven’s podcast (opens in new tab) claims, however, that “Sweet peas are hardy and can go in the garden from the middle of March.”
Confused? So were we up till we learned the RHS’s excellent sweetpea-growing tips (opens in new tab) (watch in the video above). Sweet peas are in fact “extremely tough,” says Propagation Leader Sam Gallivan, and they can withstand frosts “with no issue at all.” They do struggle with extended cold and rainy times, though. Your young sweet pea plants could perish if you reside in a region where early spring can bring both low temperatures just above freezing and a lot of rain.
Because of this, you have two options: either hold off and plant them outside in April when the weather will be warmer, even if it rains, or keep them in a cold frame until the chilly showers stop. However, sweet peas are typically categorized as half-hardy annuals and can withstand dry frost up to -4C. (25F). You will need to cover them with horticultural fleece in the event that temps fall below that.
Can sweet peas survive a little frost?
I adore annual sweet peas and believe that they are the most alluring and unforgettable garden flowers because of their beautiful scent, ruffled, winged blossoms, and treasure trove of radiant hues. These fluted beauties are excellent for cutting, and a tiny bouquet of them will fill a room with a mouthwatering aroma that makes me think of orange blossoms and honey. Sweet peas’ delicate, alluring scent is one of nature’s best-kept secrets; it has never been artificially imitated and is never overbearing or cloying.
There are now a large number of options available in a wide range of colors, from the most delicate sweet pastels to rich, vivid deep hues, including stripes and bicolors. You have a choice of classic, tall, quickly-growing vining sweet peas, non-climbing, dwarf kinds for beds and borders, and variants that cascade 8 to 10 inches in containers. All will beautify and fill the garden with a divine aroma in the spring and summer.
Sweet pea horticulture has a lengthy and fascinating history. On an island off the coast of Sicily in 1699, Father Cupani, a botanizing monk, was the first to gather sweet peas in the wild. Eckford, an Englishman, started hybridizing and selecting sweet peas in the 19th century, bringing in larger varieties in a wider spectrum of hues. These “grandifloras,” which are now referred to as “old-fashioned” or “heirloom,” were highly praised as cut flowers.
In this time, cultivars that were more suited to American garden conditions were created by American seed producers who were growing sweet pea seeds for export to the English market and for American seed catalogs. The coastal region near Lompoc, California, which is chilly, moderate, and windy, is perfect for growing sweet peas because the climate prevents the usual bee visitors from visiting the blooms, preventing cross-pollination and allowing for the preservation of exceptionally pure seed strains. Today, that region, together with England, New Zealand, and Tasmania, continue to supply a large portion of the world’s sweet pea seed.
You will find growing sweet peas to be quite gratifying if you follow the right guidelines and timing for planting. Sadly, sweet peas have a reputation for being challenging to produce, especially in the Midwest and Southeast. However, after speaking with successful sweet pea gardeners around the nation for many years, I am confident that sweet peas can thrive everywhere in the nation. Their beauty and smell are definitely worth the effort even in the rare places where they are more difficult to grow. Knowing when to plant the seeds and how to take care of sweet peas effectively are crucial.
When To Plant Sweet Pea Seeds
Sweet peas can be planted in the fall and again in the spring in regions with warm winters that experience prolonged rainy winters and cold summers, such as the Pacific Northwest. Sue, a gardener from Seattle and the creator of our website, plants seeds in April or May for “armfuls of blossoms” through September.
Plant seeds as soon as the ground is workable in rich, well-drained soil in locations with temperate winters, such as the mid-Atlantic states, which experience humid summers and early, unexpected summer heat. Don’t wait until you plant other annual flowers like sunflowers or cosmos or until the date of your last frost (sweet peas may withstand minor frosts). Your sweet peas won’t be developed enough to withstand the hot temperatures of early summer. If it doesn’t rain, make sure to water your sweet pea plants because they require constant moisture.
Nancy Hammer, a market gardener in Virginia, starts seeds indoors in jumbo packs or 4 inch pots in late March so that they can be planted outdoors as soon as they have two or three pairs of leaves. This allows her to get a head start on the season and prepare for the unpredictability of spring weather. In early to mid April, she also plants seeds straight in the ground. In this manner, she will be ready with healthy seedlings regardless of whether it is chilly and rainy well into spring or if sudden hot weather arrives.
Both Susan Keating in Maine and Jay Leshinsky in Vermont wait until the spring soil can be easily handled before planting, often in late April through mid May, in locations with extremely harsh winters like New England where the earth freezes hard and heaves. Additionally, they get a head start by starting seeds indoors a month to six weeks in advance and planting them outside as soon as the weather allows through May. In either case, keep in mind that sweet peas are unaffected by late, mild frosts. Sweet peas planted in the ground in northern regions in April and May will blossom fully in late summer and continue to do so virtually until the first frost. If the summers are particularly hot, choose a location where the vines will receive some afternoon shade and water if it doesn’t rain.
How hot can sweet peas tolerate it?
Currently, sweet peas are available in every hue but true yellow, including crimson, lavender, and navy blue, as well as certain flecked and streaked varieties. There are shorter varieties that are appropriate for containers that are only eight to 20 inches tall, but the majority of types trail for about six to nine feet.
Despite being regarded as an annual, there are a few cultivars of sweet pea that are perennial, but these lack scent. As does the everlasting pea, a related perennial plant (Lathyrus latifolius). Make sure the sweet peas you buy are scented if that’s essential to you because some breeding of sweet peas has actually preferred flower size over scent.
The essential thing to keep in mind regarding sweet peas, which are quite simple to produce, is that they prefer cool climates and need about 50 days of lows below 60 degrees to blossom properly. In colder climates, plant seeds outdoors as soon as the soil is workable in the early spring. Don’t worry if it becomes colder because seedlings can endure a little bit of frost. From spring through summer, and in some places, even into the fall, there will be flowering. A substantial layer of mulch will keep roots cool and maximize the length of the blooming period.
In the South, sweet peas can be planted outside in the fall, from early October to early November, or even in the late winter, from January to February (search for short-day types). Although they will produce roots, the tops won’t grow much until spring.
Can peas survive a little frost?
Wherever a chilly spring quickly transitions to a hot summer, as it happens in much of Minnesota, the pea growing season is brief. Areas close to Lake Superior and in the state’s far north may experience milder summer temperatures and have more time to grow peas.
Before being harvested, the majority of pea cultivars require 60 days of development. But they will stop growing and not produce flowers or pods once temperatures get above 85F, as often happens in June.
Despite the fact that the plants do require full sun, peas that are grown in hot weather may also be of low quality. It’s crucial to begin planting as soon as possible. It might be a good idea to prepare the planting space in the preceding fall.
Here are some recommendations for planting peas:
- As soon as the soil has defrosted and is usable, plant the seed.
- At the foot of the trellis, grow tall, vining variety in a single row. Trellises can have two vertical stakes connected by netting or rope.
- Close to a trellis, shorter shrub varieties can be planted in a single row. The plants will cling to and support one another if you plant them in a wide row that is between 12 and 18 inches wide.
- Be gentle with the pea seed. Cracked seeds are less likely to germinate, particularly in the early spring’s chilly, damp soil.
- Six to seven inches apart, spread the seeds out in a shallow trench. Spread the seed out over the prepared seedbed in a wide row, spacing the seeds about two inches apart in all directions.
- Put the seeds evenly into a small soil trench. Make sure they are evenly spaced apart, then add one inch of dirt to cover them.
- Over the seeds, compact the dirt. For a longer harvest period, you might plant again a week later and again a week after that.
Pea plants in their infancy can withstand brief light frosts and will thrive in any temperature above 40°F. The range of 55 to 65 degrees Fahrenheit is ideal for growing. Once the plants have started to flower and set a crop, frost can be damaging. Keep an eye out for any predictions of a late spring frost and, if required, cover the plants with sheets or row covers.
Do peas get hurt by frost?
One of those wonderful crops that does best when planted in the winter is the pea (Pisum sativum). Peas may resist some frost and can be planted in late winter for an early spring harvest, despite not being the most cold-hardy of the popular winter crops. Peas don’t overwinter well in colder locations, unlike certain winter vegetables, although they are typically the first crop that may be grown once winter ends. According to the Old Farmer’s Almanac, you can grow them in the majority of USDA zones, from 2 through 9.
Pea plants do well in cooler climates, so a few light frosts or even a layer of snow that can really protect the plants won’t harm them. The seedlings and flower buds, however, can perish in a harsh cold.
What temperature kills peas?
Beans, cantaloupe, corn, cucumbers, eggplant, okra, peas, pepper, potatoes, sweet potatoes, squash, tomatoes, and watermelon would typically all perish in a frost (31-33 degrees F).
How to sow sweet pea seeds
Sweet pea flower seeds are frequently advised to be nicked or chipped before planting, as well as to soak in water or damp paper towels for the night, although none of these steps are necessary. Sweet peas thrive in root trainers, which are unique tall plug trays, or 9cm pots since they prefer to have a long root run. But a toilet paper roll’s cardboard interior will also work.
Individual seeds can be sown in toilet paper inners or root trainers, or two to three seeds can be planted in a 9 cm pot. The container should be filled with seed compost, dampened, and then the seed should be pushed in with your finger to a depth of about 1 cm. Add some compost to the top and gradually water. Put the pots in a protected area that is well-lit. Unlike other seeds, they do not require additional heat from a propagator. When the seedlings emerge, place the pots somewhere sunny and cold, ideally between 5 and 10 degrees Celsius, or else they will grow long and lanky.
What month do you plant sweet peas?
Sweet peas can be purchased as plug plants or are produced from seed. If starting from seeds, you can plant them in the spring (February to April) or the autumn (usually October or November), and then nurture the seedlings into little plants.
Those sown in autumn and early spring need a frost-free place such as a cold greenhouse or cold frame to grow. It is better to wait and plant the seed later, in April, when you can start them off easily on a windowsill inside, if you don’t have a place that is cool and light like this. Alternately, in late April and early May, direct-sow outdoors in larger pots or the ground.
best varieties of sweet pea flowers
- The two-toned, dark pink and purple blossoms of Lathyrus odoratus ‘Matucana’ have one of the greatest fragrances of any sweet pea. BUY NOW
- The strongly fragranced Lathyrus odoratus ‘Erewhon’ blooms in exquisite mauve-pink and pastel blue hues. BUY NOW
- Lathyrus odoratus ‘Lord Nelson’ has deeper navy-blue to purple flowers that are smaller but intensely fragrant and produced in greater numbers per stem. BUY NOW
- An antique variety of annual sweet pea with vivid reddish-pink blossoms is called Lathyrus odoratus “King Edward II.” BUY NOW
- Lathyrus odoratus ‘Painted Lady’ is a popular early-flowering sweet pea with dark pink and pale pinky-white petals.
- BUY NOW
- Hardy perennial sweet pea Lathyrus latifolius ‘White Pearl’ has all-white blooms. It doesn’t have a perfume yet consistently returns year after year and blooms until the fall. BUY NOW
How to grow and care for sweet pea flowers
When your sweet pea seedlings are about 10 cm tall after spring sowing, you can pinch out the tips to help them develop into vigorous, bushy plants with lots of flowering side shoots. Just above a pair of leaves, place the growing point at the top of the stem between your finger and thumb, squeeze it, and snip it off. Avoid pinching the tips of plants seeded in the fall.
Prepare your seedlings and plugs for growing outdoors by hardening them off after there is no possibility of frost, often starting in late May. To help them get acclimated to the cooler weather, this entails leaving them outside during the day and bringing them inside at night for about a week.
Their final growing location should be in a sunny, open area with fertile soil that has good drainage. Because they climb, annual sweet peas require a support to develop. trellis, netting, a cane teepee, a border obelisk, or a garden arch are typical examples. Plant the sweet peas 15-20 cm apart, 5 cm from the base of the support you’ve chosen.
If grown in pots, plant the compost with some slow-release fertilizer to keep the plants healthy all season. Keep the plants well-watered and keep an eye out for slug and snail damage.
Sweet pea blossoms should be secured to their support as they enlarge using garden twine or support rings. Once the sweet pea blooms begin to bloom, routinely treat them with tomato fertilizer. Continue picking flowers throughout the summer because the more you pick, the more are generated.
Do sweet peas come back every year?
Sweet pea blooms come in annual and perennial varieties. Lathyrus odoratus, an annual plant that must be sown from seed every year, is typically a climber with a strong fragrance. Every spring, the perennial or “everlasting” varieties of Lathyrus latifolius reappear, however the majority of them have little or no perfume. Some don’t climb; they are bushy.