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Growing Sweet Pea

If your hands are feeling idle and you find yourself longing to get your fingers back into the dirt, sweet pea should be at the top of your list for spring planting. Sweet pea are tall elegant vining flowers long used in Victorian and cottage gardens for their fragrant and colorful blooms. Long stems also make sweet pea ideal for cutting gardens. While not the easiest flowers to grow, you can successfully grow sweet pea by following these five simple steps.

Five Steps for Growing Sweet Pea: Soak, Sew, Cut Back, Plant, Feed

Sweet pea prefer cooler weather and may be planted outside after the last frost date. Many gardeners prefer to get a head start by planting seeds in trays inside, which can be done six to seven weeks before the last frost date. You can check the last frost date for your area on the Farmers Almanac website at by entering your zip code in the search bar. Then, follow these five simple steps.

1. Soak Seeds

Sweet pea have round hard seeds that look like peppercorns. Before planting, first soak seeds in room temperature water for 24 hours. Some gardeners also nick the surface of the seed with a knife to encourage them to grow.

2. Sew Seeds

Sew seeds in a sunny area one inch deep and six inches apart. If planting in trays, place the seed tray under a sunny window or a grow light. Plants generally need eight to ten hours of sunlight daily to grow. Sweet pea seeds germinate within one to two weeks of planting. During this time, the soil should be kept damp but not wet. Overwatering can cause root rot or plants to dampen off (turn yellow and die).

3. Cut Back

Once seedlings emerge and sprouts reach six inches tall, pinch or cut off the top one inch. Cutting seedlings back is a necessary step to encourage thicker stronger stems and will cause plants to branch out (for fuller/bushier plants).

4. Plant Seedlings

If started inside, plant seedlings outside after the last frost date. Remember to harden plants off before planting them outside. (Bring trays outside during the day and inside at night for one week to allow plants to adjust.) Sweet pea should be planted in a sunny location with a minimum of eight to ten hours of sunlight per day, spaced six inches apart. Because most sweet pea varieties reach six to eight feet tall when fully grown, plants will require support (with a bamboo stake, tee-pee, obelisk, or trellis). If using stakes, consider attaching garden netting to the stakes to support a wider area of plants. If using pots, plant seedlings along the perimeter of the pot and insert an obelisk or other support structure in the center. Secure plants with string to the support structure.

Because plants grow as much as one foot each week, check them weekly and tie up new growth as stems grow taller.

5. Feed Flowers

Sweet pea are generally considered hungry plants and will require monthly feedings of high potash fertilizer. (Tomato feed generally works well.)

Flowers should emerge 90-120 days after vining. To encourage new growth, cut flowers regularly. Sweet pea typically bloom from June through October, depending on where you live and when plants were started. Flowers will last up to four days in a vase with water.

Save seed pods in the fall for planting the following year. Sweet pea are not edible plants but the seed pods do look like the edible variety namesake.

2 thoughts on “Growing Sweet Pea

  1. Great post! Sweet pea flowers have always been my favorite in the garden. Do you have any tips for keeping pests away from sweet peas, such as aphids or slugs?

    1. Hi Brent, I use soapy water with a spoon to knock aphids off plant leaves. I’ve also read planting nasturtium near plants that need protecting is a helpful distraction. Because aphids are attracted to nasturtium, they’ll go there first.

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