How to Grow Sweet Peas

Pastel-Sweet-PeasThere are some plants I wouldn’t like to be without in my garden. Lathyrus odoratus commonly known as Sweet Peas are right at the top of my list. They were the first seeds I ever sowed in the garden of our first home. Growing them got me started gardening and I have grown them every year since then. If you are new to growing Sweet Peas then please take the hint from me and have a go! They are easy to grow and very hardy so you can’t go wrong.

Sweet peas are available in a range of colours either in mixed packets or as individual colours. If you want to grow white blooms for a wedding, striking colours to add warmth to your interior decoration or pastels for a special celebration then you can select the Sweet Peas to match your needs. I have grown many different Sweet Peas over the years and I think that these are some of the best:

Cupani-ThumbnailCupani has short stems and darkly dramatic blooms with a heavenly scent.
Cupani is probably the first ever Sweet Pea collected from the wild in Italy and sent here to the UK about 300 years ago.
Although the individual flower stalks aren’t very long the plants still easily grow to 2metres/7 feet tall so they need canes and netting support just like any other Sweet Peas. They are perfect for a small vase for the house.

You can read more about them in my post The First Sweet Peas


This bunch contains some of the fantastic Spencer Waved Sweet Peas including:

The-Best-Sweet-Peas Blue Velvet which is described as deep blue but seems more purple to me.
Noel Sutton is mid blue.
White Ensign
is pure white with wavy edges
High Scent has cream flowers with violet edges.
Mollie Rilestone is white with pink edges.

There are a couple more Spencer Waved in the photo below.
Leamington is lilac/lavender.
Geranium Pink is cerise pink.
Wiltshire Ripple has claret red markings on white flowers.


The best time to sow Sweet Pea Seeds.
If you want the best possible Sweet Pea plants next year then you will need to sow the seeds this autumn. Plants grown through winter develop nice strong roots and as soon as the temperatures rise in spring then woosh there’s a rush of growth and you will see lots of fresh new stems and lush leaves. The next best thing to an autumn sowing is to sow in January or February. You can sow Sweet Peas directly into the earth but I prefer not to. There are too many creatures in my garden that simply love Sweet Pea seeds… especially mice and voles. I always start my plants off in the house. Once the seeds have germinated the mice will leave the young plants alone.

Sweet Peas like a long root run. Growing tubes or root trainers are often recommended to get the seeds started. I have found that starting them off in small modules then moving them quickly to tall pots works much better for me. A bigger root run produces much sturdier plants which in turn seem to produce many more flowers.

Please use new compost and pots. I love the look of old wooden seed trays and I am committed to recycling but when it comes to seed sowing I have to insist that new is best. New pots, fresh compost, new seed tray inserts… you get the picture. Hygiene is very important whenever you sow any seeds to prevent fungal diseases killing your lovingly nurtured seedlings. Plastic seed trays, modules and pots are inexpensive and available in garden centres, supermarkets and DIY stores. I sow a lot of seeds and I don’t use any chemicals at all. I must stress that in the garden there are always many ways to achieve good results. You may already have your favourite way or sowing seeds. Here’s my step by step method to growing the best Sweet Peas.

How to sow Sweet Pea Seeds.

This will give you enough Sweet Peas to fill two x 2 metre rows with canes spaced at 20cm/8 inch intervals

  • Two packets of Sweet Peas each containing 24 seeds.
  • One deep seed tray (no drainage holes) with a clear plastic propagator lid/cling film.
  • Seed tray inserts ideally with 24 cells.
  • A small new bag of fresh compost.
  • Plant labels and a pencil or permanent marker pen.
  • 24 x 1L plastic plant pots.
  1. Fill one seed tray insert with compost and tap the tray to settle and level the contents.
  2. Sow two Sweet Pea seeds per module spacing them as far apart as possible.
  3. Push each seed into the compost with your finger to a depth of 1cm / half an inch and cover.
  4. Insert two labels with the name and date sown.
  5. Fill the deep plastic seed tray with tepid water and stand the seed tray insert in the water for two minutes.
  6. Tip the water away and dry the tray.
  7. Allow excess water drain out of the compost.
  8. Replace the seed tray insert into the seed tray and cover with the propagator lid or cling film.
  9. Put the tray somewhere warm (18°C ) and dark such as a boiler room or airing cupboard.
  10. Check for germination each day. Your sweet peas will send up a strong shoot in a few days.
  11. When most of the seeds have germinated move the seed tray outside into a greenhouse or cold frame.
    They need plenty of light and a temperature of at least 5°C to grow on.
  12. Allow the seedlings to grow until they have produced a good shoot and healthy white roots.
  13. Pot each pair of seedlings into a deep pot at least 1Litre in size.
  14. Pinch out the growing tip when there are 3 pairs of leaves so each plant develops strong side shoots.
  15. When the plants have well developed roots they can be planted outside for the winter – they are hardy.
  16. Plant each pot containing two Sweet Peas 20cm apart with a sturdy hazel rod or bamboo cane for support.


Sweet pea plants are just like small children I think. They need feeding (incorporate plenty of organic matter in the earth around them) and plenty to drink (give them a good watering once  each week) Then they will reward you with the most lovely flowers for months.

I do hope this inspires you to have a go at growing Sweet Peas and if you already grow them to try a new colour.

If you love country gardens and grow your own flowers then I hope that you enjoyed this. I appreciate your comments and I will try to answer all your questions. Thanks for visiting.


Happy gardening.    Gillian  🙂

8 thoughts on “How to Grow Sweet Peas

  1. Oh, I would love to be able to see these growing in my garden, but it is hot, hot, very dry, very dry, scorching here!!! I shall have to borrow yours!

  2. Good clear advice, thanks. I seem to mess up at the planting out stage, but next year I think I will plant them out in the vegetable plot where there will be empty space, rather than try to find spots in the border.

    1. That’s a good idea. We built a sturdy frame with timber and metal vine eyes then each year we just feed tall canes through the vine eye rings and peg some netting over the whole thing. If you already have the structure in place and add organic matter to the earth then that’s most of the hard work done.

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