In hot, sunny weather, the soil around plants can become especially parched, and for sweet peas, can cause them to drop their flowers. Take a look at this Quick Tips video with Catherine Mansley, BBC Gardeners' World Magazine, as she provides advice on how to both treat and prevent this problem.
Sweet peas, and their relatives runner beans, are prone to dropping their flowers if the soil is too dry – and during warm weather, this becomes a serious problem.
Remove any seedpods that form, which can sap the strength of the plant, then concentrate your efforts on watering well. Water in the evening and then ensure that the entire root area is covered with a 10cm-deep mulch of organic matter. This will improve soil water retention.
Next year, dig in lots of compost before sowing.