Protecting Early Potatoes From Frost

Early potatoes are planted in spring precisely to get an early harvest — but this means their shoots emerge when spring frosts are still a real possibility. A hard frost can blacken and kill the haulms (top growth) overnight, delaying your harvest by weeks. With the right precautions, you can plant early, protect the emerging shoots, and still get that prized early-summer potato crop.

Why early potatoes are vulnerable

Potato foliage is frost-tender. When shoots emerge in March or April, overnight temperatures can still drop to -2°C or below, which is enough to blacken and kill the soft growing tips. The potato plant won't die from this — it will resprout from below ground — but set-back can delay your harvest by two to three weeks, defeating the purpose of growing earlies. Repeated frost damage progressively weakens the plant.

Earthing up for protection

The most effective and labour-free frost protection for potatoes is earthing up — drawing soil up around the emerging shoots with a hoe. This buries the vulnerable tips and insulates them from the frost while also encouraging more tubers to form along the buried stems. As shoots regrow and emerge again, earth up once more. You can repeat this process each time shoots appear until the risk of frost has passed, typically late May in most UK regions.

• Draw soil up over emerging shoots whenever frost is forecast.
• Repeat as shoots regrow — each time also increases yield.
• Aim for 10–15cm of soil cover over the shoot tips.
• Earthing up also protects tubers from greening in light.

Using fleece as backup

When a sharp frost is forecast and shoots are above soil level, draping horticultural fleece over the rows provides two to three degrees of frost protection. Pin it down at the edges to prevent it lifting in the wind. Remove the fleece the next morning once temperatures have risen — leaving it on reduces light and traps moisture. Fleece is particularly useful for container-grown early potatoes that cannot be earthed up in the same way.

What to do after frost damage

If frost hits and blackens your potato haulms, don't panic. Cut or remove the damaged foliage and wait. The plant will resprout from the crown and tubers below ground within one to two weeks. The damage is discouraging but not permanent. Continue earthing up the new growth to protect it from further frosts. In most cases, the harvest is delayed but not lost — though the timing advantage of early varieties is partially reduced.