How to Grow Sweet Peas From Seed

How to Grow Sweet Peas

How to Grow Sweet Peas From Seed

When sitting down to write growing instructions, I thought long and hard about how I germinate, plant and grow my sweet peas and I also read through at least 10 different How to Grow Sweet Peas instructions from other sweet pea experts. What I found was varying ways of growing sweet peas and sometimes conflicting advice.

Many of the growing instructions you will find online from expert growers (especially in the United Kingdom) are aimed towards producing sweet peas grown for exhibition or sale and may seem a little intimidating for a new gardener or sweet pea grower. With this in mind, I decided to write 'Basic' and 'Advanced' (coming soon) directions – sweet peas are actually very easy to grow and lengthy growing instructions should not turn any prospective grower away!

My advice is to try growing sweet peas this year, and then grow them again next year (and all the years after – they are addictive!) and you will find a way to grow them that suits you and the area you live in.

Basic Growing Directions


Sweet pea seeds
Fresh potting mix
Well rotted manure
Trellis (or some other support for the sweet pea vines)
4” pots or other small pots you have
Plant labels


  1. Fill your pots with potting soil and moisten thoroughly. I find it easier to pre-moisten potting mix by placing it in a bucket, adding water and mixing with a stick and then placing it into pots. Add enough water to make the potting soil feel like a wrung out sponge.
  2. Press the potting mix lightly into the pots.
  3. Use a pencil to create 2 holes in the potting mix and place 1 seed in each hole. The seed needs to be covered by no more that 1/4”, so don't poke the holes too deep.
  4. Place a plant marker in your pot with the name of the sweet pea variety.
  5. Place your pots on a bright windowsill and let the seeds germinate. Keep an eye on the potting mix and don't let it dry out. You should see shoots within 2 weeks or less.
  6. When your sweet pea plant has reached about 4" in height, it's time to plant it outside
  7. Dig a hole for your sweet pea and add the well rotted manure - mix it in with your soil. Remove the sweet pea from the pot and plant in the ground at the base of your trellis or other support.
  8. Water it in using the rose on your watering can or light spray from a hose.
  9. Protect from slugs, snails and birds.
  10. As the plant grows you will need to 'tie it in'. Simply use twine or some other garden string to secure the vine to your trellis.
  11. Cut flowers regularly as they fade to keep the blooms coming.
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Choose Your Pot

The deeper the pot, the longer you can wait before planting out your sweet peas. The middle pot is a 4" pot - usually available from a good garden store.

To Soak or Not to Soak?

Some sweet pea experts advise soaking the seeds before planting. Other experts say that this is not necessary or can lower the germination rate. I conducted a small test to see whether or not I should soak my sweet pea seeds.

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Carol gilson (not verified)
January 1, 2019 at 2:44 pm

Sun, shade, partial?

January 1, 2019 at 5:30 pm

Full sun.

Amy (not verified)
December 28, 2018 at 1:42 pm

How far apart do different varieties (in the same family) have to be planted so they do not cross pollinate? (First time grower here, in cotati)

December 29, 2018 at 10:37 pm

Lathyrus odoratus pollinate themselves about a couple of days before the flowers open, so it is very difficult for them to cross pollinate. 

Sweet Pea Bouquet

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