Monty Don, the celebrated horticulturist and BBC Gardeners' World presenter, has issued an urgent warning for gardeners in July concerning one specific crop: potatoes. The expert warns that potato blight, a fungal disease, poses a serious threat during this month, especially in warm and humid conditions. Don shares his personal July birthday tradition of digging first early potatoes on July 8 and advises on how to prevent and manage blight.
Monty Don's July Birthday Tradition
In his personal blog, Monty Don describes July as "a month to relish" and a time of plenty with meals eaten outside in warm summer nights. However, he notes that the light begins to draw in, making every day precious. His yearly ritual involves digging first early potatoes on his birthday, July 8, for a celebratory meal. He now grows only first earlies due to the high risk of blight.
Understanding Potato Blight
Potato blight comes in two forms: early blight and late blight. Both can rapidly damage the plant and the developing tubers. Warm, humid conditions in July create ideal circumstances for the disease to develop. Don explains that the fungi develop very fast when temperatures are high and air is humid for 23 hours, conditions increasingly common in July.
Monty Don's Advice to Save Potatoes
To save the crop, Don advises removing foliage immediately after noticing telltale chocolate-colored circular areas on leaves. He recommends composting the foliage, as the fungi do not survive the composting process, and ensuring good soil covering over the tubers. Then, wait for a dry day to harvest. First and second early varieties are less likely to be affected because they mature faster.
Preventing Blight: Blight-Resistant Varieties
To minimize blight risk, gardeners should choose blight-resistant varieties from the start. Don recommends the Hungarian Sarpo range, Sarpo Mira, Cara, and Setanta potatoes, which are renowned for their resistance to viruses and late blight.
Other Preventative Measures
Gardeners should plant in an open location with proper airflow and adequate spacing between plants to help foliage dry quickly after rainfall, hindering blight transmission. Crop rotation prevents buildup of disease spores in the soil. Additionally, treating potato crops with a protective fungicide before blight appears is recommended, starting from June and reapplying after several weeks.
