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.”
In Colorado, when can peas be planted?
At Denver’s Fairview Elementary School, an onion seedling pushes its way through the planting material. The month of March is ideal for starting indoor vegetable and flower seedlings.
Cool-season crops like peas and greens can be planted if your soil is 45 degrees or warmer.
Just be ready to protect them from any unexpected freezes.
In March, look for new growth on any ornamental grass you may have in your garden. It’s time to mow the lawn for spring if you notice the first signs of green. At the Denver Botanic Gardens in the late summer, this Pennisetum “Karley Rose” was in full bloom.
when to plant sweet peas
When between October and April, plant sweet pea seeds. Aim for late October or late November or late February or early March for the best outcomes because midwinter temperatures and light conditions aren’t the optimum. In April or May, sweet peas can also be planted directly into the ground. During a moderate period between March and May, sow your sweet pea seeds and plants.
What degree of heat can sweet peas tolerate?
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.
Are sweet peas cultivated in Denver?
A wonderful, vintage flower that your grandma might have planted is the perennial sweetpea. The keeled pea flowers grow in a clump atop tall stalks and range in color from flushed white to a rich rose pink. Grass is scant on lanky vines. If spent flowers are removed, bloom will continue from now until the beginning of fall. The spherical, spiral pods will suddenly twist open when allowed to mature, releasing their seeds high into the air and seeding a large number of new vines in your yard.
While the more common annual sweet peas struggle in Colorado’s unpredictable weather, this perennial variety does well. The plants have a lengthy lifespan; by the end of the summer, they are six feet long, and by winter, they have withered back to their roots. Some supporting netting is useful because they cling with tendrils.
Perennial peas are difficult to locate in nurseries as plants, but they are simple to grow from seed. Plant the seeds in typical garden soil in full sun to part shade after soaking the seeds overnight to speed up germination. Go gentle on the watering.
The vines go nicely with clematis and roses because of their cottage garden look, or you can grow them on a fence. They work well as cut flowers as well. The absence of the sweet peas’ lovely scent from the blossoms is the main downside.
In Colorado, when should I begin planting?
The timing of your planting is crucial because Colorado’s growing season only lasts an average of 157 days. We advise you to start all of your cold-season crop planting in April. Although it’s ideal to plant during the first week of April, cold crops can be planted at any time in April or even May.
For planting, we have created a Master Planting Document with nearly all the information you require for planting each specific plant (date, seed depth, plants per square, seed vs transplant, etc.). We advise you to print it each year for your records.
How late can peas be planted?
When should garden peas be sown? A common adage in the gardening community is to “plant peas as soon as the ground can be worked.” Sadly, it implies mid- to late March in my garden! But our lucky neighbors in the South can frequently begin planting in January and February. See my pea planting advice wherever you live.
When to Plant Peas
Garden peas (Pisum sativum L.) are a cool-season crop that can resist minor freezes and frosts but not the heat and humidity of the summer. Therefore, as soon as the land can be handled in the winter or spring, we all sow the seeds fairly early.
Check the Planting Calendar of the Almanac, which is based on your zip code, to get a basic idea of when to plant peas.
Wherever you live, plant peas as soon as you can stick your finger into the rich, dark-brown, crumbly soil because that indicates that the soil is normally ripe for planting.
The temperature of the garden is crucial. It was 52 degrees two inches down. (My soil thermometer is fantastic!)
The first crop I grow outdoors from seed is peas, which can germinate in soil as chilly as 40 degrees. We utilize raised beds so I have never had a problem with them rotting, even in a wet year. Early planting makes for soft peas.
I always had horrible peasparse and tough because I was reared in New England under the “never plant anything before Memorial Day” guideline.
That is why it is true to say that you should plant peas “as soon as the ground can be worked.” They would be fine even if a foot of snow fell on them after planting—which it frequently did.
Poor Man’s Fertilizer
My neighbor referred to it as “poor man’s fertilizer.” Really? This bit of gardening lore has some basis in reality. As the snow melts in the sun, ammonia in the air is absorbed by the snow and breaks down, releasing a little amount of nitric acid into the soil. In the past, French peasants thought that a spring snowfall was just as good as a layer of manure. Farmers in the past went a step further and plowed a spring snowstorm under.
Peas, like all legumes, can absorb nitrogen straight from the atmosphere with the aid of soil microbes that fix nitrogen. In order to help these beneficial bacteria, try moistening the seeds and rolling them in a powdered legume inoculant before planting.
To bulk up my seeds and give them a head start on germination, I soak them overnight.
If you want sweet, soft peas, put your edible-podded or classic English shelling peas to mature before really hot weather arrives.
To get the highest flavor and sugar content, plant in full light. Once the plants are well-established, a thick layer of mulch or a hilling of the soil around the base of the plants will assist to keep the roots cool and extend the harvest.
It goes without saying that a half inch of poor man’s fertilizer dropped a few days after I planted my peas! Do you have your peas yet?
For details on planting, caring for, and harvesting peas, consult the Almanac’s Pea Growing Guide!