But you can have masses of cut flowers for at least six weeks in spring and early summer, and that is enough compensation for any trouble they might be. Sweet peas can be grown, and will flower, if you just put the seeds in the ground and give them some support. However, the best results are obtained by preparing the soil in the fall. Spring sowing must be very early, usually before the frost is out of the ground and before it is any condition to be worked. Dig the ground in the fall to the depth of about a foot and if you have some good compost or manure, mix it with the soil to increase the capacity to hold moisture.
Sweet peas require alkaline conditions.
In regions with acid soil, the easiest procedure is to sprinkle enough lime on the surface to give a light-powdered appearance. They often take 3-4 weeks to germinate. I prefer sowing indoors in germinating mix in fiber pots 3 weeks before setting outdoors. That way, germination is quick and sure. Soak the seeds overnight before sowing.