I covet sweet peas for their heavenly fragrance and old-fashioned simplicity. These little vining flowers are a delight to see and smell. Sadly, they can be a tricky annual for me to grow. They prefer cool temperatures but won’t withstand a frost. If I sow the seeds in early spring in my zone 7 garden they are likely to get wiped out by a late frost. Unfortunately, mid-South springs tend to be short, so if I try sowing them any later, the plants melt in the heat before they have time to bloom.
The solution is to start the seeds in the greenhouse in February and move the pots outdoors after the threat of frost has passed. Starting the seeds indoors gives them the head start they need to bloom before spring ends.
Gardeners in climates with long, cool springs can sow sweet peas outdoors as soon as the threat of frost has passed. If you are like me and need to sow the seeds indoors, do this about 6 to 8 weeks before the last frost date in your area.
The secret to good seed germination is soaking the seeds in milk a few hours before you sow them. That’s right, milk. This helps to soften the outer covering of the seed.
Whether starting indoors or direct sowing in the garden, plant sweet peas in a spot that receives full sun. They like a sweet soil with a pH of 7 or 8, so if you know that your soil is acidic add garden lime to make it more alkaline. Be sure to following the package directions on the garden lime bag. Sweet peas have relatively extensive roots, so the soil should be friable at least 24 inches deep.
Provide immediate support for your young seedlings. Metal can get hot on warm spring days, so try twine or twigs.
Once they are up and flowering, you will want to do everything you can to keep the plants full of blooms. One of the best ways to encourage continuous flowering is to cut bouquets for the house. I like to cut the blooms about every other day. Flowers remaining on the plant will develop into seed pods. It’s a good idea to remove the flowers before this happens because you want the plant’s energy to go into creating more blossoms, not seed.