I grew them for the first time this year. They don't like to be transplanted, but since I have a short season here, I did start them indoors in pots I made out of newspaper. By the time I planted them out, after the last frost, they had roots coming out the bottom of the paper pots, and I just planted the whole thing. They grew great and bloomed all summer. I grew them up a trellis made of chicken wire. There are still some blooming right now.
Cheryl

I read and tried two years ago this little tip: dig in manure about a foot deep, a few inches below the seed depth in the sweet pea row/bed. Plant them early, they can take the cold. Out here we're supposed to plant them in Feb or March but of course I didn't get off the dime until April- they are still blooming now when normally they'd die back in mid to late July. Easy to save seeds on these if you keep a few flowers.

Support is essential. Chicken wire or netting would be easiest.

Definitely a cool season to start. Sow as soon as the ground can be worked in the spring. If you have heavy soils, prepare the ground in the fall, make a kind of raised bed and mulch it. When first nice days come in spring, pull the mulch aside to let the ground thaw, then plant ASAP. Once the plants are up, you can replace the mulch to keep the ground cool around the roots.

Normally, you'd expect the sweet peas to quit producing once really hot weather arrives in your area. Some mid to late afternoon shade may prolong the bloom period, but we rarely get away with all-season bloom in our areas.

Yes, you can transplant if done very carefully although the general recommendation is direct seeding.

Last spring/early summer I discovered "wild" sweet peas growing in an old field behind on of my fields. They must be perrenial. They had a good vase life but no fragrance. The stems were only about 8-10" long. But I sold mini bouquets with them in it. Are these just re seeding themselves or are they truly a perennial. I am in Mass, in zone 5. HEIDI

These are a perennial sweet pea. THey grow in white, pale pink and deep pink. No one will buy them in a bouquet here because they grow in massive quantities along our roadways

Prepare the bed in the fall, 6-8" deep with humus or peat moss. Before planting fertilize with a low nitrogen fertilizer, sweet peas are a legume. Roll the seeds in an inocculant and plant on St. Patricks day. Water well and cover with 6" straw. Be sure to get seeds listed as cutting flowers. Cut off the blossoms as they bloom.

Oh, I am so happy to read about sweet peas. My first time writing here, have registered a long time ago, but up til now only read all the different topics. I am German, would give my left arm, not right, to grow the flowers here in KY. After reading the tips from everyone, I will order the most fragrant sees and start next year early. Tried once before, had to kneel down to inhale one faint scent from one or 2 plants. I am exited to read the letters, what beautiful and knowledgable gardners they are. My father greww them in Berlin, I always wanted that heavenly scent here, just never could succeed, anyway, I may report back next year.
Thank you, Hildegard