How to Grow Potatoes in Bags

Growing potatoes in bags is perfect for small gardens, patios, or anyone who wants to try growing vegetables without digging. It is easy, fun, and produces delicious results.

What you need

• Potato growing bags, large pots (at least 30 litres), or heavy-duty rubble sacks with drainage holes.
• Multi-purpose compost or a mix of compost and garden soil.
• Seed potatoes (not supermarket potatoes, which may carry disease).

Choosing seed potatoes

Seed potatoes come in three types:

• First earlies: Ready in 10-12 weeks. Good for bags as they are harvested before blight becomes a problem. Examples: Rocket, Swift, Lady Christl.
• Second earlies: Ready in 13-15 weeks. Examples: Charlotte, Kestrel.
• Maincrop: Ready in 18-20 weeks. Need more space and are more prone to blight. Better for open ground.

For bags, first and second earlies are the best choice.

Chitting (optional)

Chitting means letting seed potatoes sprout before planting. It gives them a head start.

1. Stand potatoes in egg boxes or trays with the end with most eyes facing up.
2. Keep in a cool, light, frost-free place.
3. Wait until sprouts are 2-3cm long (usually 4-6 weeks).

Chitting is not essential – potatoes will grow without it, just slightly later.

Planting

1. Fill the bag with about 15cm of compost.
2. Place 3-5 seed potatoes on the surface, sprouts facing up.
3. Cover with another 10-15cm of compost.
4. Water well.
5. Place in a sunny spot.

Plant first earlies from mid-March (or later if frost is still a risk). Second earlies can go in from early April.

Earthing up

As the shoots grow, add more compost to cover them, leaving just the top few leaves showing. This encourages more potatoes to form along the buried stems.

Keep earthing up until the compost reaches near the top of the bag.

Watering

Potatoes in bags need regular watering, especially once they start flowering. The compost should stay moist but not waterlogged. In hot weather, you may need to water daily.

Harvesting

First earlies are ready when the plants flower or shortly after – usually 10-12 weeks from planting. You can check by feeling in the compost for potato-sized tubers.

To harvest, tip the bag out onto a sheet or into a wheelbarrow and pick out the potatoes. It is like a treasure hunt!

Common problems

• Frost damage: Cover emerging shoots with fleece if frost is forecast.
• Blight: Brown patches on leaves, usually in wet summers. Harvest immediately if you see it.
• Green potatoes: Caused by exposure to light. Inedible – earth up properly to prevent.
• Small harvest: Usually caused by not watering enough or not earthing up.