How to Grow Potatoes in Bags Planting
potatoes in bags is the perfect way to grow potatoes in small gardens as well as on patios and balconies. Potatoes grown this way are also less susceptible to pests and diseases, so you have a better chance of getting great results. Here’s everything you need to know about growing potatoes using this easy and space-saving method.

When to Plant PotatoesSeed potatoes, especially early and second early potatoes, benefit from “chitting.” This is the process of allowing them to “germinate” before planting to produce faster growth and heavier plants. Second crop potatoes do not need to be picked and can be planted immediately.

To harvest your seed potatoes, place them in a cool, bright and frost-free place (10°C/50°F). A reliable and tried and tested method is to arrange them in empty egg cartons or seed trays. You will notice the immature shoots sprouting from one end of the potato – the so-called rose end. Seed potatoes are ready for planting when the chips reach a length of 25mm (1 inch) and should always be planted with the rose end facing upwards.

Seed potatoes are usually about the size of a chicken egg, but don’t worry if your potatoes are different sizes – it won’t affect your harvest. In fact, during World War II, people often cut larger seed potatoes in half or even into smaller pieces to make them last longer.

If you decide to cut your seed potatoes, that’s no problem, but let them dry for three to four days before planting as normal. Provided each piece has an eye or two for new growth to develop, these tuber divisions will still harvest well.

How to plant potatoes in bags

In the past, growing potatoes in bags always required the traditional process of “soiling”: you planted your potatoes in minimal compost at the bottom of the bag and added more as the plant grew.

But while some gardeners still swear by the “old school” method, recent trials here at Thompson and Morgan show that this isn’t necessary, as long as you make sure your plants are protected from sunlight by soil and leaves. Remember: Green potatoes are inedible and should be discarded.

How to plant your potato sacks:

Fill an 8-litre potato sack with good quality, multi-purpose compost to about 1″ (2.5 cm) below the rim.
Gently submerge a single shredded potato tuber, shoots side up, into the compost to a depth of 5 inches (12 cm) above the soil surface. Carefully cover the tuber with compost.


Place the potato sack in a bright, frost-free location, water regularly and wait for your plants to grow.
Feed the potato plants with potato fertilizer every two weeks and water the bags when the compost shows signs of drying out.
When to harvest your potatoes

Harvest times vary depending on the growing season and the size you want your potatoes to be. The table above provides a rough guide for each crop, but as a rule of thumb, as ‘early potatoes’ you should start harvesting early, when the plants start to flower, around 10 weeks after planting.

For main crop varieties, allow the leaves and haulms (stems) to wilt before cutting them off at ground level and discarding them. Now wait two weeks before harvesting your potatoes to give the skins time to set properly. You should also cut off and destroy foliage if you notice any signs of rot.

Second crop tubers – or Christmas potatoes – are usually ready to harvest from late November, but you can leave them in the ground until Christmas. Cut back the foliage when the leaves start to wilt and turn yellow, and protect your potatoes from frost by either covering your potato growing bags with a thick layer of straw or bringing them into your shed or greenhouse.

If you’re not sure if your potatoes are ready, a quick way to find out is to gently dig beneath the surface to check how big they are. If they’re too small, just leave them for another week or so, lift them up, and enjoy!