How To Grow Sweet Pea Flowers From Seed

If you have ever had the chance to smell a bunch of Sweet Pea flowers you will know how delicious their fragrance is, one of the best smelling flowers! 

Sweet Pea (Lathyrus odoratus) seeds are traditionally sown on St Patrick’s Day (March 17th) and throughout Autumn, but if you live in super cold frosty areas it's best to wait until Spring. 

There are 3 main types of sweet peas that need a certain amount of sunlight and will flower in different seasons. Elegance needs around 10 hours of daylight, and will flower in Winter if planted in Autumn. Mammoth need around 11 hours of daylight and will flower in Spring and Spencer need around 12 hours of daylight and will flower in Summer, Spencer varieties are heat tolerant.

Sowing Sweet Peas

  • Before sowing Sweet Pea seeds, it is essential you prepare your soil as Sweet Peas are heavy feeders. Digging in compost, rotten manure and organic fertizler will ensure your soil is rich in nutrients and keep your sweet peas happy, healthy and well fed! Sweet Peas also desired well draining soil. 
  • Soak the seeds overnight, this will soften the hard outer seed coat and help speed up germination (* soaking is not required on the sweet pea turquoise lagoon).
  • After soaking the seeds can either be direct sown straight into the prepared garden beds, 25mm deep. Alternatively they can be started in the greenhouse in single cell deep root trainer pots. Care must be taken when transferring seedlings as they can suffer from transplant shock.
  • When direct sowing the seeds, or transplanting your seedlings into the garden, plant them 20cm apart, a little room between plants will give airflow and help prevent powdery mildew. They are best planted in an open sunning areas with at least 6 hours sunlight, basically the flowers need plenty of sunshine but their roots to be kept cool.
  • The seedlings can be pinched out at 10cm (snipping the top off) for bushy plants, which will then produce more flowers.

Growing Sweet Peas

  • Sweet Peas are an annual climbing plant that can grow up to 2 meters, they will need a trellis to climb up and you will need to tie young seedlings to the trellis as they grow.
  • Protect Sweet Peas from wind. Making sure they are planted in a sheltered area. 
  • Feeding your sweet pea plants weekly seaweed treatments will help keep the nutrients up to the heavy feeders.
  • Sweet Peas require regular and deep watering.
  • For longer stems, make sure you cut the side tendrils of regularly.
  • The flowers will be ready to harvest when there are at least two un-opened blooms on the stem. The more you pick the more flowers they will produce. To extend vase life, change the water regularly and add in a spoonful of sugar.

Sweet Peas are a such an amazing beneficial flower, as they are in fact a type of legume and will add nitrogen to the soil.  

Saving Sweet Pea seeds is very easy, let the flowers turn into pod, once the pods have turned brown they can be collected and stored in a paper bag in a dry area.

Unlike normal Sweet Peas, Sweet Pea Lathyrus odoratus seed and seed pod are not to be eaten, as they are considered toxic to humans and animals.

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