Monty Don has revealed a simple yet effective method to prevent tomato blight: stripping off the lower leaves as fruits develop. In his July blog post, the gardening expert described this as the "best defence" against the disease, which can cause near-total yield loss in warm, wet conditions.
Why Blight Strikes in Late July
Blight is a fungal disease that affects tomato foliage and fruit, causing rot. It thrives in high humidity combined with warm days and nights, conditions that become more common from late July onwards. While greenhouse tomatoes are less susceptible, outdoor plants face significant risk. Monty Don explained: "From late July, the risks of blight increase, dependent as it is upon the combination of high humidity and warm days and nights."
The Best Defence: Stripping Lower Leaves
Don's recommended prevention is straightforward: "The best defence for outdoor tomatoes is good ventilation and stripping off the lower leaves as the fruits develop, which helps this." Removing lower leaves not only improves air circulation around the plant but also allows ripening tomatoes to receive maximum sunlight. This dual benefit reduces humidity around the foliage and speeds up fruit ripening, minimising the window for infection.
Additional Tomato Care Tips from Monty Don
Don advises planting outdoor tomatoes in June, then tying them up regularly as they grow. He also removes side shoots and waters thoroughly. For indoor tomatoes, he provides a weekly seaweed feed, noting that his outdoor soil is "plenty rich" and does not require additional fertiliser. Regular monitoring throughout summer is essential to catch any issues early.
