Seven Grower’s Secrets:
How to Grow Unusually Beautiful Sweet Peas
#1 How to Know When to Plant
When to plant sweet peas is important to their success. Sweet peas will blossom profusely with superior quality flowers when planted so that they have a long growing time in cooler weather. A general rule is to plant sweet peas six weeks BEFORE the last frost date in your area. In South, Southwest or areas with hot summers – Planting seeds in fall is recommended. In more moderate climates – Sweet peas will give you glorious results if planted October – April. In areas with cold winters and hot summers – Pre-starting plants (see tip #4) is beneficial, allowing sweet peas the longer growing time needed.
#2 How to Know Where to Plant
Sweet peas will flourish if planted in a sunny spot. These climbing annuals will need vertical support. For best results, plant in well-cultivated soil, rich with composted manure.
#3 How to Ensure Good Germination
Use clean, fresh seed. Soak seeds overnight. To hasten germination, any seed not swollen after soaking may be chipped (use a razor blade to chip or break through skin on seed).
#4 How to Get a Jump on the Season with Hardy Plant Starts
Start seedlings in an unheated greenhouse, cold frame or outside in a protected area. Don’t baby this hardy frost-tolerant annual.
#5 How to Keep Plants Free of Pests and Stimulate Plant Growth
Foliar feeding of plants with a weak manure tea will make foliage distasteful to aphids as well as stimulate plant growth and keep them a healthier green color. Guard against aphids, as they may transmit disease to plants.
#6 How to Prolong Blooming
Flowers will bloom for a couple of months with frequent pickings. The more bouquets you cut, the more the plants will blossom. Remove seedpods.
#7 How to Grow Unusually Long-Stemmed Flowers Throughout the Growing Season
After sweet peas have been blooming for awhile, flower stem length will naturally shorten. To regain longer stem length, add a small amount of bloodmeal to the soil by sprinkling it alongside the plant, cultivate in and water thoroughly.
Frequently Asked Questions
How many seeds will I need?
Plant sweet pea seeds – one seed every 6 inches. For a 10 foot fence or wall you will only need 20 seeds.
What should I use for a trellis for my sweet peas to climb?
Sweet pea vines will need vertical support - use wire, string, or plastic trellis netting. These Spencer sweet peas will climb 6 – 9 feet tall – so trellis should be about 6 feet tall. One of the best ways to grow sweet peas is to plant them on a freestanding trellis. Plant on both sides of the trellis to double the amount of flowers. For maximum sunlight, place the trellis so it runs from north to south.
Will sweet peas grow in a container?
Sweet peas can be grown to bloom beautifully in a container. Choose a container that is at least 10 to 12 inches deep. This may be the best way to take advantage of your yard’s best sun. Container grown sweet peas will still need a trellis.
Foolproof germination - use the "wet paper towel method” of starting seeds.
Moisten a paper towel so that it is saturated and very wet. Lay it flat on a counter. Place sweet pea seeds in the center of the paper towel and fold into a rectangle with seeds inside. Place in a plastic bag (I use a 6-1/2’ x 5-1/2” plastic sandwich bag). Leave in plastic bag for 5 – 6 days. Open up bag to check seeds – all should have germinated or swollen up. Plant seeds in either a seed flat, pot or directly in the ground. Any seeds that are still small and hard should be “chipped” with a razor blade. This means taking off a small piece of the skin of the seed to reveal lighter color underneath. Plant these seeds too.