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  • Growing Sweet Peas- A Beginner's Guide

    December 29, 2022 5 min read 0 Comments

    sweet peas

    Sweet peas make the perfect cut flower to grow from seed

    Even if you are not an experienced gardener, you will have no trouble growing these beautiful, sweet-scented flowers. The sweet peas seeds are large enough to handle and germinate pretty easily. 

    Sweet peas come in a large variety of colors, making them perfect to pair with other flowers for early-season bouquets from your cut flower garden. You can choose from the standard size, which will grow to about 6 ft, or you can pick bush varieties. 

    Sweet peas have various types: the scented and annual growing Lathyrus odoratus and the unscented and perennial Lathyrus latifolius. Be sure you are buying seeds of the kind you want to grow. This information should be on the packet of seeds. 


    Depending on your growing zone, you will either plant sweet peas in the late fall or late winter to early spring. For warmer zones, zone 7 and above, you can plant sweet peas in the late fall. For colder zones, sow in late winter or early spring. 

    Sweet peas are a cool-weather plant. So it is crucial to get them blooming before the heat of the summer comes. Sweet peas are a cold-hardy annual and can handle a light freeze but need protection when temperatures fall below 25⁰F. 


    Sweet peas have a harder outer shell. Some of the seeds will be harder than the rest of the package. This hard outer shell is nature's way of ensuring the seeds stay viable until the weather is more favorable for them to grow. Sweet peas benefit from being soaked in water for 24 hours before planting to help break down the outer shell. The seeds will swell after they have soaked. If you notice that some seeds have not swelled, take them out and scratch the seed with a nail file or clippers. Place those seeds back in the water until they have soaked up water before planting. 

    grow from seed


    You can get a jump start on their growth by starting sweet peas indoors. You will be able to get earlier blooms and ensure good germination rates. 

    Start sweet peas indoors 4-6 weeks before planting them out. You do not need to start them any earlier as they do not like becoming root-bound. Growing them in 2.5" seed starting pots gives them the space that the roots need to grow healthy. Sweet peas germinate in darkness; they will need to be buried deep enough that 1/2 inch of soil is covering the seed. 

     Using a humidity dome will increase humidity and speed up germination. Place your tray of newly sown sweet peas under grow lights or a very sunny window. Once germinated, remove the humidity dome to ensure proper air circulation. 

    When seedlings are about 6 inches tall, you can pinch the growing tip and transplant them into the garden. They will tolerate a light freeze, but if you expect a hard freeze, use frost fabric to protect them. 


    Sweet peas will need a trellis to climb, and it is best to put this in place at the same time as planting the seeds. You do not want to disturb the roots later. Sweet pea seeds need to be planted ½ inch deep for proper germination. They need the darkness to germinate—space seeds out to every 6 inches. 


    Once the plants are about 6 inches tall, pinch off the central growing tip to just above a leaf joint. Be sure to leave 2 or 3 leaf nodes. You can use garden snips for this or simply use your thumb and pointer finger. Pinching sweet peas will encourage branching growth, resulting in bushy plants and more blooms.

    Sweet peas like to grow up towards the sun to receive as much light as possible. Pinching encourages the plant to redirect all of its energy into growing more stems and leaves, resulting in more blooms. And more bouquets as well! 

    sweet peas


    Sweet peas need a steady supply of water. They do not like to dry out. Setting up a drip system is a great way to ensure they are getting the water they need. You can also mulch with organic material. My favorite mulch is shredded leaves. They are free and provide nutrients to the soil as they decompose. 


    Soil richness is essential when growing sweet peas; you will want to be sure you give them plenty of nutrients. You can add compost to the top layer of soil, organic fertilizer, or work in cow or chicken manure. If you feed them well, they will produce strong stems and lots of blooms. 


    Sweet peas are a cool-season crop, but they also need lots of sun. Spring can sometimes be tricky to work out this balance. Growing crops under and around sweet peas can help keep their roots cool, and while they climb the trellis, they will still receive lots of sunshine. You can plant small annuals near your peas like calendula, marigolds, or pansies. 

    How to keep sweet peas flowering

    To keep sweet peas flowering, you will need to cut the flowers. Cut flowers for bouquets when there are at least two flower buds unopened. If you do not cut them for bouquets, be sure to deadhead them before they begin producing seed pods. Once they produce seed, the plant has done its job by reproducing and will not continue to give new blooms. 


    If you want to prolong your harvest of flowers, succession planting is the way to go. Plant out small batches every couple of weeks and support once grown with trellis netting. This will lighten the workload and stretch out the harvest dates. 

    Growing Sweet Peas for Bouquets

    There is something special about being able to go out to your garden and cut your homegrown flower bouquets. Sweet peas benefit from cutting the flower stalks. The more you cut, the more beautiful, sweet-smelling sweet pea blooms the plants will produce. 

    A freshly picked bouquet of sweet peas can last around 5 days in a vase and will have your home smelling beautiful early on in your growing season. When you need to discard the spent bouquet, more flowers will be waiting for you to harvest. 

    Sweet peas aren't difficult to grow as long as you give them the right circumstances. Be sure they have good rich soil, a trellis to grow on, and pick them often, and you will be on your way to falling in love with growing these every spring in your garden. 

    Written by Robin Lapping @robinsroots