Sweet peas are one of the few annual flowers with enduring appeal and rural charm. They appear to be the exact opposite of our hurried life as they twine languidly around a rustic trellis. Sweet peas are fantastic flowers for gardens and bouquets thanks to their alluring scent. For information on how to plant and care for sweet peas, read our Sweet Pea Growing Guide!
About Sweet Peas
The sour pea Lathyrus odoratus is an annual flower that looks great twining on a trellis or arch, growing in a cutting garden, border garden, or woods. Today, a wide variety of hues, from pearly white to ice cream pastels to ritzy magentas and inky purples, are available for the blooms.
Only their honey and orange blossom fragrance matches their delicate winged flowers. Their appeal has been ensured by the combination of their exquisite aroma and their capacity to generate a large number of flowers for the house over an extended time of cutting.
One of the keys to cultivating sweet peas is to sow them early. Sweet peas are incredibly tough, despite the way they appear fragile. Plant them in very late winter or early spring in USDA Hardiness Zone 7 or colder, as soon as the soil is dry enough to work with. (Don’t plant seeds after the last frost.
When Dr. Robert Uvedale, a teacher from Enfield, Middlesex, received seeds of this exceedingly fragrant annual in 1699 from a Sicilian monk named Francis Cupani, he brought the first sweet peas to Britain. In North America, they gained enormous popularity as garden plants and cut flowers. By the late 1800s, producers in California, especially W. Atlee Burpee, were exporting trainloads of sweet peas across the nation and creating numerous new varieties.
Some people liken the process of producing sweet peas to that of preparing pie dough. Some individuals are gifted, while others are not. This plant sprouts from large, manageable seeds that resemble peas. They are still rather challenging since they take a while to germinate. It’s worthwhile to experiment with various seeds every year.
When to Plant Sweet Peas
- Sweet peas should be planted as soon as the soil is dry enough to work in very late winter or early spring in most places where frosts occur frequently (Zone 7 and colder). (Start sowing before the last frost! Most certainly, it will be too late.)
- Plant sweet peas in the late fall (November) if you garden in a region with a mild winter climate (Zones 8, 9, or 10), so they can grow and blossom in the late winter and early spring. Six weeks before you plant the seeds, dig a trench and fill it with compost or well-rotted manure to obtain the greatest show. Sweet peas are gregarious plants that require a lot of nutrient-rich materials to flourish.
Sowing Sweet Peas Indoors
- Start sweet peas inside in a seed tray to get a head start on the season in the coldest regions of the nation. Sweet peas can withstand light frosts, so plant out as soon as the soil can be worked in early spring, around 6 to 7 weeks before the last date for frost.
- The seeds’ outer layer is softened and helped to germinate by soaking them overnight. Using a nail file to lightly score the outer shell can also be beneficial.
- 2 seeds to a module is fine to sow the seeds, but keep in mind that their lengthy roots have a propensity to tangle and can make separation challenging. Sow the seeds around half an inch deep in each cell of a seed tray.
- Scoop them out gently after they start to sprout their first pea-like leaves and place them in a larger container to harden off. One of the most reputable growers of sweet peas gave me the following piece of advice: “Treat the seedlings like I would treat my husband: put them in an unheated greenhouse, neglect them, and they will thrive.
- Plant them outside as soon as the soil can be worked.
Sowing Seeds in the Ground
- Sweet peas thrive when their roots are firmly planted in cold, wet soil and their heads are exposed to sunlight. Plant low-growing annuals in front of them if you can to provide shade for the roots.
- Pick a spot that drains effectively. If your soil tends to be acidic, it is recommended to add some powdered lime to the surface.
- Mix liberal amounts of compost or well-rotted manure into the ground to a depth of two feet to create a rich soil. (Learn more about adding amendments to the soil and getting it ready for planting.)
- You should dig a beautiful, deep “compost trench” that is around 4 inches deep before planting.
- After digging the trench, use a pencil to cut holes, place the seeds inside, and then press down on the earth to compact it and block out any light.
- The seeds should be soaked in water for 24 hours prior to sowing. To hasten sprouting, nick the seeds with a nail file before planting. In a temperate climate, seeds don’t need to be soaked.
How to Grow Sweet Peas
- Depending on the soil temperature, germination after planting can take anywhere from 7 to 15 days.
- Fill in the trench gradually as the seedlings appear and develop. Hoe additional dirt toward them.
- Keep the soil wet. Summer rains may be plentiful. Sweet peas can have bud drop; if you stick your finger into the soil bed to its first joint and the soil is dry, water them at the soil level and do so in the morning.
- You won’t need to fertilize if you plant with a lot of compost and aged manure. Use high potash feeds if you do want to supplement the diet because nitrogen feeds promote excessive top development.
- Mulch well once plants are planted to keep the soil cool and moist. Unless the soil becomes dry, you might not need to water your sweet peas if you mulch.
- Pinch off the tops when plants are 6 inches tall, not sooner, as this will promote the production of side shoots too early.
Provide Supports
- When temperatures rise above 65°F, sweet peas will begin to fade since they like chilly days and nights.
- Sweet peas are true climbers, with the exception of the bush forms. Provide them with sufficient support for at least 6 feet. Some species can reach heights of nine or ten feet. A braided willow obelisk, bamboo poles in the tee-pee design, or a trellis are examples of other attractive supports. If you don’t have a fence or trellis, give them something to cling on, such chicken wire, bushy twigs, or brush.
- Give the plants a good start by tying the first few stems to the support; the rest will follow. When they reach a height of 4 to 8 inches, use your thumb and forefinger to pinch out the middle growing point. Plants will grow stronger as a result.
Picking Flowers
- Pick flowers frequently for bouquets so that the plant will focus its energy on producing additional blooms rather than seeds. Up until the first frosts, the more you pick, the more they produce.
- Allow a couple of the final blossoms to mature into seedpods when the leaves begin to lose their color. On a windowsill, dry them, and then keep in an envelope in a dry location to sow the following year.
From miniature bedding kinds ideal for pots and borders without support to 8-foot-plus scramblers, there are sweet pea varieties for every setting.
These decorative peas are native to Sicily, where they have flimsy stems and a powerful orange-jasmine-honey aroma. Modern hybrids feature larger blooms and stronger stalks.
However, some of these contemporary kinds, despite having larger blossoms and more fashionable colors, lack the earlier sweet peas’ perfume. Sweet pea ‘Cupani’ is still rightfully well-liked and simple to grow. It has bi-colored flowers with maroon upper petals and violet “wings.”
The decadently fragrant “America” is an antique from 1896. When its petals open, beautiful red and white wavy stripes are revealed.
Look for antiques like the Sicilian “Old Spice” collection. Shades of white, cream, pink, lavender, and purple can be seen in this strain’s blossoms.
A new cultivar with enormous, creamy-yellow blooms with violet shading called “April in Paris” is aromatic.
Although the ordinary sweet pea is an annual, Lathyrus latiflolius, a perennial broad-leaved everlasting pea, is not fragrant. These clambering plants have a height of up to 6 or 7 feet, are hardy to zone 5, require little care, and bloom continuously from year to year.
- An essential component of a late Victorian garden is the sweet pea. Because of their wide range of colors and aroma, Victorians adored sweet peas.
- When the dew is still on the flowers in the morning, gather them. Their best aroma is at this time.
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.
When are sweet peas too cold to grow?
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 sweet peas require stratification in the cold?
Some seeds, like perennial Sweet Peas or Pansies, require special care in order to break dormancy and germinate. If you’ve ever questioned why certain seeds from brand-new plants never seem to germinate, cold stratification might be the answer.
Stratification sequences may differ, according to Master Gardener Susan Patterson: “Some seeds demand a warm and moist treatment, while others require a cool and wet treatment.” Other seeds, however, need a mix of warm and cool treatments, followed by a warm treatment, or a warm and cool moist combination, followed by a dry cycle and a warm phase. Before starting any seed stratification endeavor, it is essential to understand what seeds need to emerge from dormancy. In order to expose the seed to air and moisture, certain plants also require stratification from heat, such as from fires.
Cold and moisture are the two main conditions for cold stratification. It is better to plant when winter is expected to last, depending on where you reside. The seed coat can break down and there may not be much germination if you sow when it’s too warm.
However, if you are starting in the early season, soak your seeds for 12 to 24 hours before placing them in a plastic bag or other airtight container with sand, peat, or an equal mixture of the two. Label and date. See if they are sprouting frequently. Some seeds must be stored in the freezer for a longer time than others.
According to Pinetree Garden Seeds, “soaking them in cold water for 6 to 12 hours prior to beginning the process can help reduce the overall stratification time needed. Additionally, this aids the seed in absorbing some of the moisture it needs for the upcoming chemical processes.
1) If your plant reseeds, you can simply disperse your seed as soon as it seeds if it doesn’t matter where the new growth appears. Any unruly plants that sprout up against your garden plan can be moved to where you might decide you want them, given away as a last resort, or eaten if it is acceptable, or composted. For breadseed poppies, I employ the broadcast technique. However, occasionally you might change your garden layout to make room for what you hope will turn out to be a magnificent display of beauty!
If you have a seed packet, a more formal approach would be to choose the location, prepare the soil, and scatter your seeds there in the fall. Put a tag on the location, date, and information. Keep them moist; when they are ready, they will sprout.
Floods or drastically changing weather, such as cold, hot, and cold, could be risks of these two strategies. Just in case, keep some extra seeds on hand. Then you move on to way #2, or you can practice both method 1 and method 2 just in case.
2) You might apply the paper towel technique. Put the seeds on one side of the towel, moisten it, then fold it over to cover them. Place the towel inside a plastic bag and zip it up. Place it in the refrigerator and wait. Some advise checking every two to three days and getting rid of any mold. Others advise waiting 10 days. Some estimate that it could take a month or two. They should be thrown away if they develop brown spots around them or begin to smell musty. However, the key goal is to keep that towel damp!
If you already have a seed package, here is myseedneeds’ recommendation for poppies for the lazy gardener! We advise a brief cold stratification period of 6 to 12 weeks, but gardeners who don’t want to deal with damp paper towels and plastic baggies can just store their seed packets in their crisper drawer for a few months.
You could also soak your seeds first. Put equal amounts of sand and peat in a pot and add worm castings to aid with germination. Place your seeds in. Put the pot or container inside the refrigerator, on the ground in a protected area, or buried up to the pot’s top on the north side of your building, which is more exposed to the elements. Keep those seeds moist at all times.
Restoration Seeds published this thorough guide to How to Germinate Your Seeds on Permaculture News. It gives more alternative Cold Stratification methods and incorporates them! starting at the Cold Stratification section. Great advice! Read this!
Harold and the Cats of Alchemy make a crucial point about sustainability: “Seeds…won’t come up all at once, way the seeds of most cultivated plants are bred to do.” Because they are more like to the wild and hence have a solid motive to stagger their germination, seeds that use cold to germinate are more likely to survive and produce more genetic variation. This implies that there will be a higher possibility of receiving plants that will thrive in your environment.
On a seed packet, terms like “self-sowing,” “perennial,” “cold hardy,” or “cold stratification” are signs that your seeds might benefit from cold treatment.
Numerous Common Domestic Flowers are significant companion plants, including Sweet Peas, Zinnia, Johnny Jump Ups, BreadSeed Poppy, Cosmos, and Pansies.
Wildflowers! Here is a great MAP to help you choose local wildflowers that need to be cold-stratified before being planted in the spring in your area. United States Meadows Native wildflowers make excellent companion plants because they draw local bees. Make sure to start early enough to allow for planting time because they need to stay in your fridge for 4 to 5 weeks. Your seeds will grow nicely and germinate more quickly. For monarchs, don’t forget to plant native milkweed!
Numerous perennial common herbs serve as significant veggie companion plants, food for pollinators, and companion plants: Sage, Rosemary, Lavender, and Calendula
Make careful to look up each plant separately to learn about its unique requirements, such as length of time and temperature. An illustration of the perennial Oriental poppy (Papaver orientale) can be seen at SFGate. Some poppy varieties are easy to plant, whereas Oriental poppy varieties require special care!
- In a plastic bag, put 2 tablespoons of perlite or sand. It should be mildly dampened with water, but not made soggy.
- Mix 1 tablespoon of poppy seeds with the perlite or sand before adding them to the bag.
- For two weeks, store the sealed bag in the fridge. Check on it every so often, and if additional water is required, give it some, to keep it moist. Keep it from drying out.
- Take the bag out of the fridge, and keep it somewhere cool and dry for a week. Put the bag back in the fridge for an additional two weeks.
- For six weeks to three months, repeat this cold-thaw cycle. In the early spring, scatter the layered poppy seeds over moist soil. When the soil temperature is between 55 and 60 degrees Fahrenheit, they will begin to sprout in about two weeks. [Therefore, begin your procedure well in advance!]
Cold stratification is a straightforward method that, while it may need some commitment, definitely pays off!