Why Grow Early Potatoes in Bags?

If you have a patio, balcony or small courtyard, you can still enjoy the unbeatable flavour of home-grown new potatoes. Early potatoes—also known as first earlies—are the quickest cropping type, ready in as little as ten to twelve weeks. Growing them in bags is clean, space-saving and ideal for UK gardens where soil may be heavy, stony or simply unavailable. You can move the bags to catch the sun, protect them from late frosts, and harvest without a fork. Best of all, you avoid many soil-borne pests and diseases that plague open-ground crops.

Choosing and Chitting Your Seed Potatoes

Start with certified seed potatoes, not ones from the supermarket. Good first early varieties for the UK include 'Rocket', 'Swift', 'Lady Christl' and 'Pentland Javelin'. These are bred for earliness and reliable yields in our climate. Buy them in January or February and set them to chit. Stand each tuber upright in an egg box, with the rose end—the end with most eyes—pointing up. Place in a cool, light, frost-free spot, such as a windowsill or shed. In four to six weeks you will see short, sturdy green or purple sprouts. If more than four appear, rub off the weakest to focus the plant's energy.

What You Need for Planting

Gather your materials before planting time, which is usually late March to mid-April, once the risk of hard frost has passed. You will need:

• Large bags: 40–50 litres minimum. Purpose-made potato bags or strong compost sacks with drainage holes.
• Compost: multipurpose compost mixed with a little garden compost or loam for body. Avoid heavy clay soil.
• Feed: a handful of potato fertiliser or fish, blood and bone per bag.
• Drainage: a few stones or broken pots at the bottom of each bag.

Fill each bag with about 15 cm of compost. Sit three or four chitted tubers on top, sprouts facing upwards, spaced evenly. Cover with another 15 cm of compost and water gently until moist but not soaking.

Earthing Up: The Secret to a Bigger Harvest

As shoots emerge and reach about 5–10 cm tall, cover them with more compost, leaving just the top leaves exposed. Repeat this every week or two until the bag is nearly full. This process, called earthing up, encourages the plant to produce more tubers along the buried stems. Never let tubers be exposed to light, or they will turn green and become inedible. Keep the compost consistently moist—like a wrung-out sponge—but never waterlogged, as soggy compost rots tubers.

Caring for Your Growing Crop

Water regularly, especially once flowers appear, as dryness at this stage reduces yield. Feed every fortnight with a liquid potato fertiliser or a general tomato feed. In cold snaps, throw fleece over the bags or move them into a greenhouse, porch or cold frame. Early potatoes usually escape potato blight, which tends to strike later in summer. Watch for slugs and aphids, and pick them off or use a barrier. A sunny, sheltered spot gives the best results.

Harvesting and Enjoying Your Early Potatoes

First earlies are ready about ten to twelve weeks after planting. The signal is when flowers open or buds drop. For true new potatoes, harvest while the foliage is still green. Tip the bag out onto a sheet or reach in carefully with your hands. Take only what you need, leaving the rest to grow on. If you want to store them, cut the foliage down and leave the tubers in the compost for a few days to firm their skins, then brush off dirt and keep in paper sacks in a cool, dark place. Nothing beats the taste of your own buttery new potatoes, straight from patio to plate.