At Kings we just love sweet peas mostly because they do a bunch of things. They are reasonably easy, they grow during the cooler months, they can climb or ramble or not, they are very cut-able and they smell wonderful. Here are a few tips on sweet peas so you can have fun and success.
When to plant: As mentioned, Sweet Peas like the weather on the cool side, on the other hand, they need a bit of warmth to germinate and eventually bloom. In Sonoma County you may direct seed into the prepared soil in August, September and October. This gives the plants time to sprout before it gets cold. Normal frosts will not kill the plants. Indeed, during the cool winter, the roots continue to grow providing strength in very early Spring. If you have missed the direct seeding time, you may start them indoors and plant them outside anytime during the Winter and all the way through early Spring.
Location: Full Sun to no less than half a day of full sun.
Germination: Most folks find this pretty easy. In the ground, care should be taken to prepare the soil deeply, to about 12” or more if you are energetic. After working the soil, add MasterNursery Pay Dirt and Master Start and work again. Water so the soil is moist, not soggy and plant the seeds about an inch deep.
Keep evenly moist, but not soggy. Over watering can rot them. Another method would be to prepare the bed early and plant the seeds right when the Winter rains are starting. For indoors we use MasterNursery Potting soil right out of the bag, filling six pack, small pots or greenhouse/flat kits designed for starting seeds. Again the seed is placed about an inch deep and watered several times thoroughly. Then we cover the flat with a layer of newspaper and moisten the paper. After this whole thing stops draining, I bring it inside to a warm cozy spot with some bottom heat if you have it. The top of the refrigerator, back of the stove, nice window. Water thoroughly again when it is dry. There is no need for daily water, only when necessary. Germination can happen as soon as 7 days. Once sprouted, remove the newspaper and put them in a sunny location until a couple of inches high, then outside to a sheltered spot, then into the garden or containers. Some folks soak the seed overnight before planting, we find that this is generally not necessary. However, some seed packets are marked nick before sowing. In this case you can soak the seeds or slightly chip the seed coat with a sharp knife on the opposite side of the seed eye.
Growing: Most sweet peas need a structure. The exceptions are dwarf and knee high varieties, which can be grown with or without support and even in hanging baskets and on the sides of containers of you do not mind the sprawl look. Your structure can be as plain or as fancy as you like, but please make it sturdy and bit bigger than you think that it ought to be. We have used bamboo hoops for smaller varieties, large wigwams of willow or tied together wigwams of bamboo or redwood. Trellis against or tie to fences or wire frames. We have also attached a trellis to a large container with great success. Whatever the method you choose, remember that when the young peas reach out for support, they will need to be gently tied, especially at first and in a timely manner. As the stems age they can become a bit brittle, making the job difficult. We find that once they are started out on the right track they keep on track fine just by themselves. Spacing for new plants should be about 6 to 8 inches apart in your prepared soil. Please remember to work the soil. Your ultimate results are always tied to the soil. Subsequent feeding can be any complete food. We recommend slow release Osmocote or MasterNusery Bud and Bloom. Whichever you choose, please do it. Those nasty snails can be a problem when your plants are young and defenseless. We now have pet-safe snail baits as well as the traditional type, put that out when transplanting.
Other Stuff: Keep the flowers cut. This is important and fun. Sweet peas are cool season annuals and will produce armloads of flowers if you cut the spent ones off as soon as they start to drop petals. This will provide you with non-stop bouquets with room-filling fragrance, and will bloom for weeks and weeks. As the weather warms in Spring, please water your peas consistently as this will also increase length of bloom.
At Kings we carry 30 to 70 different varieties of sweet peas depending upon the time of the year. We have standard varieties such as Winter Elegance and Royals. These are also many times available as plants. Also available are some very old fashioned varieties dating to the 1700’s. These usually have substantially smaller flowers but are wildly fragrant. We also have, and specialize in, English Spencer varieties that have enormous wavy flowers and extra long stems along with fragrance. These are the varieties that are featured at the world famous Chelsea Flower Show. Have fun, plant some of each.