Plant some sensational sweet peas

Plant some sensational sweet peas

While St Patrick’s Day (March 17) is considered the traditional date for sowing sweet peas, in warmer climate areas such as Perth, it’s safer to wait until April or May. Once the soil is cooler, there’s a lower risk of the seeds rotting before they germinate.

March 31, 2021
Colourful sweet peas

Sweet peas are one of the most popular winter flowering annuals. They put on a long-lasting display of vivid hues, from purples and pinks, to reds and white. Sweet peas make excellent cut flowers to brighten up your living spaces.


While sweet peas need plenty of sun, a Perth spring can produce very hot days. Your sweet peas will do better in a spot which gets the morning sun, and afternoon shade. Also, choose a spot with good drainage.


Sweet pea seeds are best planted directly into the garden bed about 3cm deep and 7cm apart into soil that is slightly alkaline. Add compost or well-rotted manure prior to planting. Potash is also good as it’s based on calcium carbonate and potassium carbonate. Calcium makes the soil slightly alkaline and potassium promotes healthy, vigorous growth.


Depending on the variety of sweet pea you choose, you may need to provide support for your plants such as an arch, teepee or trellis. The support only needs to be basic, as they are not heavy plants. Dwarf varieties don’t need support.

Tips for success

  • Avoid using too much fertiliser (particularly high-nitrogen feeds) or plants will produce lush green leaves but very few flowers.
  • Mulch and water well for good flower production. Once they start to produce, be sure to pick stems every other day to prevent seedpods maturing. The more you pick, the more flowers the plants will develop.
  • Pick flowers in the morning and place immediately into a vase of water if you want to display them indoors.
  • Avoid over-watering and wetting the foliage. Instead water at the roots.

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