How and when to earth up potatoes

There are few more satisfying achievements for a gardener than reaping the rewards of their labours.

For some, that might be the simple pleasure of sitting back and enjoying the glorious vision of a full, blossoming flower bed. For others, it might be digging up your produce to cook up for dinner. And nothing really tastes sweeter than home grown potatoes.

But how and when do you earth up potatoes to ensure your crop is the best it can be?

Spring is the best time to plant potatoes and this can be done right up until the end of May. To grow well, potatoes prefer to be positioned in full sunlight and planted in loose, well-drained soil which is kept watered and which is rich in nutrients. Sandy soils and loose loam soils are favoured but potatoes can also thrive in peat and clay soils as long as water can drain off. What potatoes cannot tolerate is soil which becomes waterlogged as the tubers will rot.

Growing potatoes is a game of two halves with work going on both under the ground and above. As they grow underground, potatoes develop roots and lots of small tubers – or potatoes. A good plant can produce up to a kilo in tasty spuds.

Overground, thick, green shoots will grow to a height of 60 to 100cm. A technique called earthing up will protect these shoots from frost damage and ensure the developing potatoes are not exposed to light which will turn them green and inedible.

Earthing up potatoes involves building up the soil around the leafy shoots when they reach about 10cm tall. To do this, loosen the soil between the rows using a garden fork. Then use a rake or spade to draw the soil into a ridge along the length of the row around the emerging stems of the potatoes. Rake up the soil until only 5cm of stem is left visible above ground. It is also a good tip to leave a shallow trough along the row at the top of the ridge so any water can be channelled down feed to the developing tubers.


As the potatoes continue to grow, the shots will appear again so the vigilant gardeners should repeat this earthing up method twice or three times when the plant reaches 10 to 15cms above ground – usually about every three weeks.


The technique can also be employed for potatoes grown in pots. Make sure you only half fill your pot with compost before planting your potatoes and then you can put more compost in as the shoots grow above the earth.


The result…beautiful spuds for everyone to enjoy.


For more advice, or if you have any questions about potatoes or any other gardening queries, speak our friendly team in store or get in touch on [email protected]