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Is it too late to plant sweet peas?

Sweetpeas are a wonderful flower to grow, both looking and smelling absolutely amazing. In order to get the very best out of them you need to get them started early, this leads to many people wondering when it is too late to plant sweetpeas, well join me as I jump in and investigate this question.

When to plant sweetpeas?

This question will obviously vary based on the time of year that you are reading this article, lets’s start by listing the regular sowing dates for sweetpeas.

Oct – April Sow Indoors

This is the regular sowing time for sweet peas if you are growing them indoors or in a heated greenhouse. You can sow from October and overwinter the seedlings as is often done with regular pea cultivars.

March – Early May Sow Outdoors

You can sow direct into the soil outside where the plants are going to be growing from march onwards. This obviously varies depending on whereabouts in the country you are. I for example cannot sow sweetpeas direct to the soil in March up here in northern England, it is simply way too cold.

You can sow all the way up until May and get good growth and blooms, mid to late may however is a little late for me to simply plant some sweet pea seeds in the soil and hope they will grow in time.

Sowing in May

This is probably as late as you can get away with sowing sweet peas. Even now you may not get as many flowers on your sweet peas as you would if you had sown them earlier, it is still possible to get good displays, however.

If sowing this late there are some extra steps you should take to maximise growth.

To start with I would advise soaking the peas in water for 24 hours before planting the seeds. This should help to speed up germination a little and every day saved here is an extra day for growth before summer fully arrives.

I would also grow the plants indoors or in a greenhouse until they are well established. This will help to speed up the growth and allow the plants to catch up to ones sown earlier. Essentially you need to do all you can to promote fast growth at this stage so the flowers have a chance of growing well before flowering.

Mixed colours of sweet pea flowers
Mixed colours of sweet pea flowers


sweet peas, (Lathyrus odoratus) are a flowering plant belonging to the legume family. They are an annual flower that loves to climb and spread, in the right conditions and with the correct support they can grow to 2 and a half meters tall!

Unlike many other legumes which are grown to be eaten, sweet peas are grown for purely aesthetic reasons. There is evidence to suggest that the pea seeds from a sweet pea plant are actually toxic to humans and not fit for consumption even if this was desired.

Sweetpea FAQ’s

Are sweet peas perennial?

No sweet peas are an annual plant, they will not come back year after year.

Can you eat sweetpeas?

No, sweet peas are grown purely for their looks. Unlike many other legumes, they are actually toxic to humans if consumed.

Are sweet peas poisonous to pets?

Yes, as they are poisonous to humans they are also poisonous to pets, so make sure you keep an eye on your pets when they are hovering around sweet peas.

How high can sweet peas grow?

With the proper support, sweet peas can grow to 2m or even slightly above!

When do you grow sweet peas?

The traditional season for sweet peas is June and July but with the right care and attention, they can be both started earlier and grown later into the season. Regular deadheading of sweetpeas can massively prolong their flowering period.

How to germinate sweet peas?

I like to soak my sweet pea seeds in water for 24 hours before planting them in a seed tray. This soaking helps to break down the tough shell around the seed allowing them to germinate better.