Sweet peas are cheery little blooms that will brighten up a landscape, growing atop leafy green vines that will climb over a fence or twine around a trellis. Although sweet peas prefer full sunshine, their blooming season is longer in cooler climates. The bright blooms look like little butterflies, and when they fade, they will be replaced by pods that will provide plenty of seeds to save for planting next year.
Allow a few sweet pea blooms to fade naturally on the vine. The blooms will fall off and be replaced by long, bright-green pods.
Keep an eye on the sweet pea pods. As they dry, they will turn greenish-yellow. When the seeds inside are fully developed, the pods will be dry and pale brown in color. If you shake the pods, you can hear the seeds rattling inside.
Remove the dry pods from the plant and put them on a tray. Put the tray in a cool, airy place to let the pods continue to dry for a few more days.
Break the pods open with your fingertip, if they haven't already split, and the tiny, grayish-brown seeds will fall out. Put the sweet pea seeds in a regular white envelope, label the envelope, and put it in a cool, dry place until spring.