You can get a surprisingly large haul of delicious new potatoes by growing them in a simple sack on your patio. What’s more, if you plant them in August or September, you could be harvesting them on Christmas morning! Generally speaking however, first early potatoes planted in February can be ready around 10 weeks from the planting date, while second earlies take a fortnight longer. Maincrop potatoes, planted from March to mid May, usually take around 15 to 20 weeks to harvest. To speed up the process (especially with first and second earlies), people often ‘chit’ the potatoes. This simply involves placing each tuber in an individual hollow of an egg box or seed tray, with the eyes facing upwards. Place the tray in a cool, bright, frost-free position. You’ll soon notice lots of little sprouts appearing. Once they’ve chitted, fill your bag up to a third high with organic compost. Place a couple of chitted potatoes on top, then fill another third and add two more. Finally fill to the top with compost, and water thoroughly.

Planting seed potatoes ‘Charlotte’ in a growing bag – Water well once foliage has formed – © Maxine Adcock/GAP Photos
If the bag is placed in a sunny position, green sprouts will soon be visible over the top of the compost. Water regularly and feed with potato fertiliser every fortnight. The time it takes to harvest varies according to the type of potato you planted and whether you want baby new potatoes or you’d rather wait for larger tubers. Once your plants begin to flower, it’s a good sign that the first earlies can be harvested as new potatoes. If you gently scrape away some of the soil at the top of the bag, you’ll see how large the tubers are – if they’re still too small, cover them back up with compost and wait another fortnight. Maincrop potatoes are generally left for a fortnight or more after the foliage has started to dry up and die back. If foliage is turning yellow or brown you can cut it with secateurs and add it to the bonfire. Avoid composting potato foliage as this can spread blight.

Planting seed potatoes ‘Charlotte’ in a growing bag – Harvesting the potatoes – © Maxine Adcock/GAP Photos
When the potatoes are ready to harvest they should be spread regularly throughout the bag. A great advantage of growing them this way is that they are very unlikely to be damaged by pests such as slugs and eelworms – so almost every tuber will be blemish free. Carefully check through the entire bag as there are bound to be a few elusive marble-sized spuds. Brush off any lumps of compost. You may want to eat some of your harvest right away, but place the other tubers in a dry, airy spot to allow the skin to harden and dry out. Then you can store them in hessian sacks or paper bags. Avoid using polythene bags to store potatoes as this encourages them to rot.
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