Now is the time to start Sweet Peas for winter and early spring production. Sweet Peas (Lathyrus odoratus) are members of the legume family Fabiaceae which hail from Southern Italy, Sicily and the Aegean Islands.
Henry Eckford of Scotland is responsible for the incredible crosses which produced many of the famous heirloom varieties known today. The noted beauty and fragrance is a direct attribute of the careful breeding by Eckford in the late 1800s through 1906. The breeding production of today focus on stem length and lasting abilities of cut flowers.
Sweet Peas require scarification (nicking or abrading the seed coat to enhance seed germination). Warm water soaking of the seeds may also enhance germination.
Use a nail file or nail clippers to nick the seed coat. The nicking or “chipping” will speed up the germination process. By the way, this is a tedious process. Make sure you give your self plenty of time to keep on schedule for your planting area.
Planting in large cell packs or 4″ pots for transplants is a proper way to plant exactly where you desire. Start the process by using a soiless soil mix with generous compost added. Make sure the soil is adequately moist and plant the seed 1″ deep. I usually plant two seed per cell or pot. Once planted, water in the cell packs/pots and place where the soil temperature is 65° to 68° (F). I know that sounds pretty cold but that is what sweet peas prefer.
The correct germination temperature will insure proper germination in 7 to 10 days. When most of the seeds have germinated move the seed flats to a much cooler area (45° to 55° (F)). A mildly heated greenhouse, coldframe or hoop house will do the trick. Sweet pea seedlings can take it down to 32° (F). The added benefit is stronger and cold tolerant seedlings.
Sweet peas may be bothered by aphids when planted outside. The aphids spread disease and stunt the plants and subsequent production. The other area for concern is powdery mildew. Powdery mildew is caused by too much shade and poor air movement. Watch cultural practices (such as full sun and planting further apart to provide air circulation) to prevent the scourge of this pernicious disease.
Be careful with sweet pea seeds! They are toxic for consumption. If you have small children the seeds could be enticing!
I will keep you posted on future development.