Potato blight is a devastating fungal disease that begins by attacking the haulms, but if left unchecked, it is quickly washed into the soil by rainfall, causing the tubers themselves to rot, which renders them either inedible or impossible to store long-term. This fungus thrives and spreads rapidly during periods of high temperature and high humidity—specifically when those conditions persist for around 23 hours—a climate pattern that has become increasingly frequent throughout July.

The good news is that your crop isn’t necessarily doomed if you act decisively. If you spot those characteristic, circular, chocolate-colored patches appearing on your leaves, you must immediately remove all the foliage. This step is critical, as those spots are an early warning sign that the disease is spreading and will soon cause the plants to collapse. Once you have cleared away the affected tops, you can safely compost them because the fungus cannot survive the composting process. To provide extra protection, ensure there is a thick, solid layer of soil covering the tubers to prevent the spores from washing down onto them. From there, simply wait for a dry day before lifting your harvest to ensure the best possible outcome.

If you are looking to avoid this stress in the future, it is worth noting that first and second early potato varieties are generally far less susceptible to blight. Because these varieties reach maturity much faster than their late-season counterparts, they are typically ready to harvest well before the high-risk conditions of mid-to-late summer take hold. By prioritising these earlier types, you can often enjoy a successful harvest while avoiding the peak window for fungal outbreaks entirely.