When you lift your crop will depend on the growing season, weather conditions and size of potatoes you want.
• First Earlies can be harvested as ‘new potatoes’ after at least 10 weeks when the plants begin to flower.
• Second earlies should be ready after about 13 weeks
• Maincrop varieties 16-20 weeks after planting.
Potatoes will generally get larger the longer they grow.
Maincrop potatoes are usually left in the ground for at least two weeks after the leaves and stems have withered – this allows the skins to harden, which helps them store better.
Cut the stems off to just above the soil surface when the leaves die back.
You should also cut the stems and leaves off if they show signs of blight (a disease affecting potatoes – brownish black spots appear on leaves and stems). Doing this stops the spores washing into the soil and affecting the tubers. Don’t compost stems and leaves from blighted crops.
Try to harvest on a sunny day when the soil is dry. Leave the tubers on the surface of the soil for a few hours to dry and help the skins harden. When they are dry store them in paper or hessian sacks in a cool, dark place. Don’t store them in plastic bags as they will sweat and rot.
If growing in a bag or container, once you have harvested your potatoes empty the compost onto the garden or into a compost bin if you have one. You need fresh compost/soil each time you plant new seed potatoes