It’s the peak of the growing season with gardeners busy planting flowers, fruit and vegetables up and down the country. This will include tomatoes, which are one of the most popular crops to grow.
They can be grown from seed or purchased as young plants to be grown outdoors or in a greenhouse, where they grow especially well. Like potatoes, tomatoes are susceptible to blight so need plenty of care, especially if grown outdoors. There aren’t any fungicides against blight available for gardeners.
Tomato blight is caused by a fungus-like organism which affects leaves and fruit in warm, wet weather. The Royal Horticultural Society (RHS) describes blight as “very serious” for tomatoes grown outside, with those indoors less likely to be affected but still susceptible.
Guy Barter, Chief Horticulturalist at the RHS, told the Express there are three tomato varieties which are deemed resistant to blight. These are crimson crush, cherry crush and honey moon.
Such cultivars aren’t usually totally immune. They will probably succumb to blight to some extent during prolonged spells of the kind of weather the disease thrives in. However, they may still give a “good” yield compared to more susceptible cultivars, according to the RHS.
Blight symptoms usually start with rotting leaves, which shrivel and turn brown. A white, fungus-like growth might also appear on the underside of leaves. You might also spot fungus on affected leaves, which is a grey-brown colour.
Light green lesions are further signs of blight, as are brown lesions, which can develop on stems and leaf stalks. Green fruit can see patches of brown in another sign.
The RHS advises against adding material from infected plants to compost bins and recommends putting them out for green waste collection or burning them.
Any equipment that has come into contact with an infected plant should also be cleaned with a disinfectant before being used again to help contain the disease.
Picking off infected leaves might slow blight’s progress, but it won’t get rid of it, according to the RHS advice.
Keeping foliage dry in greenhouse grown tomatoes can also help keep blight at bay. The BlightSpy website is one way of getting ahead of the disease as it forecasts when blight will be active locally.
The RHS advises against using soil or compost from an affected crop to grow tomatoes next year.
Most infections are from wind-blown spores coming from other gardens and allotments, as well as from commercial potato crops.
In the UK, outbreaks can happen from June onwards and are usually seen first in the South West.
Outdoor tomatoes are especially susceptible to certain weather. Blight is less of a problem under glass because the spores have to find their way into a greenhouse. However, high humidity in a greenhouse often results in the disease rapidly taking hold.
For more information on how to guard against blight, visit the RHS.
