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.
Do sweet peas withstand frost?
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.
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.
Do pea plants require protection from 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.)
The plants can survive temperatures as low as 10 degrees Fahrenheit (-15 degrees Celsius) or even 5 degrees Fahrenheit (-12 degrees Celsius) if snow has fallen and covered the peas.
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.
Should sweet peas be covered?
Sweet peas climb by wrapping its tendrils around the support frame, however sweet pea support rings are useful for directing them.
As your plants begin to run off, keep an eye on them and continue to tie them in as they grow. Over the course of the entire growth season, you must perform this every 7 to 10 days. For straighter cut flower stems, encourage the plants to grow vertically up the frame.
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.
When are peas too chilly to eat?
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. However, as temperatures get beyond 85°F, as they frequently do in June, they will stop developing and cease to produce blooms or pods.
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. Frost can be harmful to plants once they have begun to blossom and produce a yield. Keep an eye out for any predictions of a late spring frost and, if required, cover the plants with sheets or row covers.
Do sweet peas return each year?
Although Lathyrus odoratus, the most popular sweet pea variety, is an annual, there are also perennial forms available (Lathyrus latifolius).
- 1. Annual sweet peas are plants that go through their entire life cycle in a single growing season. They grow, produce seeds, and perish within the span of a year, just like other annual crops. The next year, you must replant new plants in your garden if you want to grow them again. The majority of sweet pea species are annuals.
- 2. Perennial sweet peas: These flowers reappear each year. After the growth season is over, you don’t need to replant them because they will keep growing for a longer period of time. Although there are fewer types of perennial sweet peas available and they tend to lack the traditional sweet pea aroma, they may be simpler to grow.
spring
- From March to May, you can easily plant your young sweet pea plants outside. Before planting out, sweet pea seeds sown in the winter or autumn need to be potted up into larger containers. Spring-sown seeds can be transplanted from their rootrainers.
summer
- Pick your sweet peas, then put them in indoor vases. Remove the seed pods from your sweet peas to continue deadheading them. You’ll need to harvest and deadhead them frequently when they’re at their height.