Planting Sweet Peas

Posted in Gardening Tips on March 15 2011, by Sonia Uyterhoeven

Sonia Uyterhoeven is Gardener for Public Education.

A month ago we discussed the history of the sweet pea (Lathyrus odoratus) with the focus on uncovering which sweet peas will grow well in the short springs and the warm summers in the New York Area. Some varieties are definitely more heat tolerant than others and the new day neutral varieties such as ‘Winter Elegance’ and ‘Velvet Elegance’ flower up to 2 weeks earlier than older varieties.

So what are the basics for getting your sweet peas in the ground and growing? If you live in a cool climate and would like to get an early start then you can plant them indoors 6-7 weeks before the last frost date. If you would like to wait and direct sow then wait until a month or so before the last frost date. In the New York area you will be sowing them outdoors somewhere between the beginning and middle of April.

Sweet peas will germinate faster if you either nick the seed coat or soak them for several hours in lukewarm water. Sweet peas like to be planted in full sun although if you live in a place where the summers get hot quickly you can try morning sun and bright afternoon shade.

You will improve growth is you amend the soil ahead of time with either compost or aged cow manure. Sweet peas prefer good drainage. Plant your seeds one inch deep and space them 2-3 inches apart. Once they begin to grow, thin them out to 5-6 inches.

You will encourage lateral branches and get a fuller plant if you pinch your sweet peas back when there are 3-4 sets of leaves. Pinch back to 2-3 sets of leaves just above the leaf node.

Young seedlings are in danger of being eaten by slugs, snails and birds. Cover the young plants with bird netting and used your favorite slug repellent when the seedlings are young and tender.

Mulching and keeping your sweet peas well watered will improve their growth. Once they start to produce flowers make sure you pick them on a regular basis to promote more blooms.

Smaller dwarf varieties such as ‘Pink Cupid’ can stand on their own, but most sweet peas need vertical support to thrive. Remember that sweet peas have tendrils that like to cling to and wrap around supports. Galvanized wire cages make easy supports. Bamboo trellises or teepees also provide good places for peas to climb.

Sweet peas are not related to edible peas – they are poisonous and should not be eaten. They make wonderful cut flowers and their fragrance is one of the nicer fragrances that you will find in the spring.