Extending Sweet Pea Flowering.
Sweet Peas a great cut flower for the home
Sweet peas (Lathyrus odoratus) are treasured for their beautiful colours and intense fragrance and easy to grow from seed , but their bloom period can feel all too short if you don’t give them a bit of extra care and planning. With the right techniques, you can significantly stretch the time your sweet peas produce flowers.
1. Pick Often — The Key to Continuous Blooming
Sweet peas respond strongly to deadheading and harvest. Removing old blooms prevents the plant from putting energy into seed production, which naturally slows and eventually stops flowering. So, the more you pick, the more flowers the plant will make.
💡 Tip: Always snip off the whole flower stem, not just the faded petals. This tells the plant it hasn’t completed its job yet and encourages more flowering. This practice is widely recommended in other UK gardening advice too — regular removal of spent blooms keeps plants productive.
2. Train Plants to Flower Freely with Early Pruning
When your young sweet pea plants are still small, pinch back the growing tips. Doing this encourages them to develop side shoots and a bushier structure, giving more places for flowers to form later. More side shoots = more potential blooms.
3. Feed Carefully for Longer Flowering
Sweet peas benefit from regular feeding once established:
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Use a dilute liquid fertiliser every two weeks during the flowering season.
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Avoid heavy feeding if the plants start producing lush leafy growth instead of flowers.
Feeding fuels the plant’s energy reserves, which supports ongoing bud formation and sustained flowering.
4. Use Artificial “Long Days” in a Greenhouse
Flowering in sweet peas is influenced by day length: longer daylight encourages them to keep blooming. If you’re growing sweet peas under cover (in a greenhouse):
📍 At the end of July, consider installing a normal lamp on a timer that stays on for about two hours after dusk.
🌙 This makes the plants “think” summer days are longer, helping them continue flowering later into the year.
While this is mostly useful for greenhouse growers, understanding the plant’s sensitivity to light helps you choose sowing dates and varieties that suit your climate.
5. Stagger Your Sowings for a Long Season
Instead of sowing all your sweet peas at once, stagger successive plantings over a period of weeks:
🌱 Sow the first batch in early spring or late winter (indoors/undercover).
🌱 Sow additional batches every 2–3 weeks until early summer.
This approach means you won’t end up with all the plants peaking at the same time — as the early plants begin to slow, the later ones are just getting going.
6. Environment & Support Matters Too
Although not mentioned in the original article, other practical care tips help extend flowering naturally:
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Supports: Sweet peas are climbers — give them sturdy trellis, netting or cane frames to climb.
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Airflow & spacing: Good airflow helps prevent disease and keeps plants vigorous.
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Water & nutrients: Regular watering and occasional balanced feeding ensure plants stay healthy and capable of sustained bloom production.
Stretching the Sweet Pea Season
To maximise your sweet peas’ flowering period:
✔ Deadhead religiously — pick more to get more.
✔ Pinch out growing tips early to encourage branching.
✔ Feed fortnightly with a weak liquid fertiliser.
✔ Use artificial lighting in a greenhouse to extend day length.
✔ Sow seeds in succession to keep blooms coming.
With these steps, you’ll enjoy fragrance and colour for as long as possible from these classic garden favourites — turning a few weeks of blooms into a much longer flowering display.
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