August and September are sweet pea planting months for us here in the mild-winter west. A great selection of sweet pea seeds are available to choose from including the earliest bloomers and the very popular Old Fashioned varieties. Old Fashioned sweet peas are particularly fragrant.
Sweet peas are cool weather annuals. Sweet peas germinate when the ground temperature is a uniform 55-65 degrees. Once germinated, the plants thrive at temperatures from 70 to 80 degrees. Above 85 degrees, they really struggle. They hate hot, dry winds. If you live in an area where the transition from cold winter temps to hot summer temps happens quickly, you should consider starting your seeds indoors and transplanting. Start your plants six to eight weeks before you plan to transplant them.
Sweet peas planted now, in a manure-rich soil, will sprout and establish themselves well before winter cool temperatures arrive. The earliest ones can actually bloom as soon as January as they require just 10 hours of sunlight per day to set buds. The later varieties will be nice large plants by the time early spring arrives and will set a profusion of blooms. Sweet peas are beautiful and fragrant and they make great cut flowers.