TO START OUTDOORS: In late spring, once weather is warm and settled and nights stay above 50°F (10°C), plant seeds in a sunny spot in ordinary garden soil 6 inches apart and 1/2 inch deep. Firm soil over seeds.
TO START EARLY INDOORS: Sow indoors 5 to 6 weeks before last expected frost in individual pots of seed starting mix. Cover 1/2 inch deep and keep warm and moist. Provide a strong light source until seedlings are ready for outdoor planting. Transplant very carefully once nights stay above 50°F (10°C). Thin or transplant seedlings 10 to 12 inches apart. Do not disturb delicate roots.
GROWING NOTES: To speed germination, soak seeds for no longer than 8 hours in tepid water. Plant immediately after soaking. Erect well-anchored supports at least 8 feet tall at planting time; strong netting, a wood or wire fence or a sturdy trellis serve well to hold these vigorous climbers that bloom hard from midsummer.