Growing sweet peas: Problems and solutions

If you’re experiencing flowers falling off sweet peas, the chances are it’s not caused by insects or disease. Instead, it’s likely to be caused by the weather and the environment.

Hot, sunny weather can lead to the soil around the plants becoming dry which can cause dropping of flowers. Both runner beans and sweat peas are prone to flower drop if the soil gets too dry.

Early in the season it’s more likely that we’ll experience warm days and cold nights which can have an impact on the plants. So, to stop this being a problem for your sweet peas, delay planting by about two weeks to reduce the likelihood of flowers dropping.

If there’s a temperature drop forecast, protect the young plants that are already outdoors. Also, be sure to harden off plants raised indoors before planting out.

Equally, ensure the water being used to give moisture isn’t icy cold because this can shock the plant and cause the flowers to drop too.

As a solution, remove any seedpods that are forming because this will direct the energy back into the plant’s growth, and keep watering deeply and well to moisten the soil. The trick is to water during the evenings when it’s cooler and ensure the soil is covered with mulch at about 10cm thick which will retain moisture, insulate the roots, and suppress weeds.

Seedlings of sweet peas might begin to grow leggy. This is when they grow upwards and have a slightly scraggly appearance rather than looking full and healthy. This can be caused by insufficient light and excess warmth. If this seems to be the problem, seedlings can be moved to a cooler and brighter spot.

However, you can also encourage side shoots to grow by pinching out the tips of the plants by snipping off the top of the stem slightly above a set of leaves. This will therefore support dense and bushier growth to make the plant more sturdy.

If the sweet peas are growing on canes or trellis, the long stems can be trained along the ground and tied into a separate cane for them to grow upwards on.

Unfortunately, young sweet pea plants are prone to slug and snail damage, but there are a few ways to control or prevent this from happening.

If you spot slugs and snails on the foliage, physically remove them by hand or using chopsticks to rid them of the area.

Alternatively, take advantage of companion planting methods by planting strong scented plants like lavender, rosemary, and fennel as a deterrent. The other option is to offer sacrificial plants that slugs and snails do like to encourage them to those rather than feasting on your sweet peas. Good examples are nasturtiums and hostas, that slugs will appreciate.

If you’ve found that the leaves of your sweet peas are turning yellow, this is likely down to overwatering which has resulted in root rot. On the other hand, it could be a sign that the compost is too nutrient rich, which has led to the roots burning.

Therefore, before planting ensure the soil is well-drained rather then heavy and wet. Once planted, water as necessary to keep the compost moist but not wet. In the UK this will probably mean extra watering isn’t necessarily needed unless there are prolonged dry spells.

• When growing sweet peas from seed, water the seedlings and young plants regularly until they are planted out and established. Mulching can help to keep the compost moist too.
• A tomato fertiliser that’s high in potash is ideal to encourage more flowers rather than a fertiliser that’s high in nitrogen that encourages more foliage.
• Remove spent flowers and seedpods because sweet peas won’t produce new buds whilst there are still old flowers and seedpods on the plant.