Expert garden advice from the RHS: when is the best time of year to sow sweet peas?

The experts at the RHS answer your gardening questions...

Question: I have sown sweet peas for the first time, last autumn, because I read it was preferable to sowing them in the spring. However they are already looking rather leggy. Should I give them up and sow another lot this spring? I read you got better and stronger plants if you sowed the previous autumn.

Answer: It is a good idea to sow sweet peas in autumn, for weather-tolerant, sturdy plants. The key is to sow in a cold greenhouse in October. The seeeds will germinate with no extra heat and the seedlings can be hardy to well below freezing.

Once the plants have three sets of leaves, pinch out the growing tip, just above the second set of leaves. This will encourage bushiness and stronger stems bearing more flowers. As long as the ground is not frozen or waterlogged, you can plant out from now onwards.

If you sweet peas have been grown in the house, they will become leggy, with long stretches of stem between leaf joints. It's lucky that now is the perfect time to go again, sowing into pots and keeping in a cool room before hardening off to much cooler conditions once the seeds have germinated. Growing them on the hard side will pay off in the end.

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