Sweet peas are one of the great joys of summer gardening, a quintessentially English flower that is now grown by gardeners worldwide. The sweet pea's colorful blooms and spicy scent make for perfect cut flower arrangements, and it is generally easy to grow, provided the plant gets enough water.
But did you know that watering incorrectly will have a detrimental effect on sweet pea flowers? Learning how to grow sweet peas is all about making sure they have adequate moisture – but it turns out it really does matter where your water comes from. Professional sweet pea grower Derek Heathcote explained why in a recent episode of Gardeners' World.
The one thing you must never do when watering sweet peas
Derek owns the specialist sweet pea nursery Eagle Sweet Peas and has, by his own admittance, grown sweet peas all his life, following in his father's footsteps (he also had been a gardener).
While describing his growing sweet peas as a life-long passion bordering on obsession, Derek admits that growing sweet peas isn't always straightforward. In particular, he explains that sweet peas 'shed their buds when the conditions aren't correct for them.' Extremely frustrating for a beginner sweet pea gardener.
The shedding of buds can happen for several reasons, most commonly during spells of unseasonably cold weather, during a heatwave, or even after a thunderstorm, as Derek points out. But while there's not much you can do about what nature has in store for summer weather and the effect it has on your container gardening ideas, there is one fully preventable reason sweet peas shed their buds.
'One thing you must never do is water them from the [cold] tap, or with a hose pipe', cautions Derek. The water is too cold, and the buds shed themselves.'
What is the correct way to water sweet peas?
Derek says that his top tip for watering sweet peas is to 'keep the ground moist at all times.' As with watering plants in general, allowing the roots to dry out will have dire consequences for these thirsty flowers. Sweet peas in particular love moist soil and will decline quickly if allowed to dry out.
The best way to water them is out of a watering can (as demonstrated in the Gardeners' World episode), but you will want to feel the tap water first. If it's very cold, mix in a little hot water. You want the effect of warm summer rain, so aim for room temperature.
