Monty Don, the renowned horticulturist and BBC Gardeners' World host, has issued an urgent warning for gardeners to harvest their first early potatoes immediately or risk losing them to potato blight. In his July gardening advice, Don emphasizes that warm, humid weather creates ideal conditions for the fungal disease, which can quickly destroy both foliage and tubers.
Monty Don's Birthday Tradition and Potato Blight Risk
Don, whose birthday falls on July 8, has a personal tradition of digging up first early potatoes on that day for a celebratory meal. He notes that the harvest varies depending on planting time and weather, but the ritual is a practical response to the high risk of blight in July. According to Don, potato blight is a fungal disease that first rots the haulms (stems and leaves) and then, when washed into the soil by rain, attacks the tubers, making them inedible or unstorable.
“I now only grow first earlies because the risk of blight is so great,” Don shares. He explains that the fungi develop very fast when temperatures are high and humidity persists for 23 hours—conditions increasingly common in July. The crop can be saved if foliage is removed immediately after telltale chocolate-coloured circular areas appear on leaves, which quickly spread and cause collapse.
How to Protect Potatoes from Blight
Don advises gardeners to remove all affected foliage and compost it, as the fungi do not survive the composting process. He also recommends ensuring good soil coverage over the tubers, then waiting for a dry day to harvest the crop. First and second early varieties are less likely to be affected because they mature faster and are ready for harvesting earlier in the season.
Potato blight comes in two forms: early blight and late blight, both of which can damage plants and underground potatoes. To prevent the disease, gardeners should take preventive measures at the sowing stage, such as choosing blight-resistant varieties like the Hungarian Sarpo range, Sarpo Mira, Cara, and Setanta potatoes, which offer excellent resistance to viruses and late blight.
Preventative Measures for Healthy Crops
Additional steps to reduce blight risk include selecting an open planting site with adequate airflow and allowing sufficient space between plants. Improved airflow helps foliage dry quickly after rainfall, hampering the spread of blight. Crop rotation also prevents accumulation of disease spores in the soil and ensures infected plants do not grow from overlooked tubers from the previous year's harvest.
Gardeners may also treat potato crops with a protective fungicide before signs of blight emerge. Don advises beginning treatment in June, particularly during wet weather, and reapplying after several weeks to safeguard new growth. By following these expert tips, gardeners can enjoy a healthy potato harvest despite July's challenging conditions.
