You don’t need a vegetable patch to grow potatoes. A few grow bags on a patio, balcony, or driveway will produce a surprisingly generous harvest of fresh, flavourful spuds that taste nothing like the waxy things from the supermarket. Growing in bags is simple, requires minimal space, and is one of the most rewarding things a beginner gardener can do.
Why Grow in Bags?
- No digging required — just fill, plant, water, harvest
- Works anywhere — patio, balcony, driveway, even a sunny doorstep
- No soil-borne disease risk — fresh compost each year means no blight carryover from previous crops
- Easy harvesting — tip the bag out rather than digging
- Brilliant for beginners — potatoes are one of the most forgiving crops to grow
Choosing Potato Varieties
Potato varieties are classified by how long they take to mature:
| Type | Plant | Harvest | Time to Harvest | Best Varieties for Bags | Best For |
|---|---|---|---|---|---|
| First Early | March | June–July | 10–12 weeks | Rocket, Swift, Casablanca | New potatoes, salads |
| Second Early | March–April | July–August | 13–15 weeks | Charlotte, Kestrel, Nicola | Salads, boiling |
| Maincrop | April | August–October | 18–20 weeks | Maris Piper, King Edward, Sarpo Mira | Roasting, mashing, chips |
First earlies and second earlies are best for bags — they mature faster, take up less space, and are harvested before blight typically hits in late summer. The RHS potato growing guide has comprehensive variety recommendations for UK conditions.
What You’ll Need
- Seed potatoes (not supermarket potatoes — buy certified disease-free seed potatoes)
- Potato grow bags (40–50L capacity) or large hessian/polypropylene sacks
- Multi-purpose peat-free compost
- Liquid tomato feed (for feeding from flowering onwards)
- Watering can
Step 1: Chitting (Optional but Recommended)
Chitting means encouraging the seed potatoes to sprout before planting. It gives them a head start and can improve yields, especially for first earlies:
- In late January or February, stand seed potatoes upright in an egg box or seed tray
- Place in a cool, light position (a windowsill in an unheated room is ideal)
- Wait 4–6 weeks until sturdy shoots appear (10–25mm long)
- When planting, handle carefully to avoid breaking off the shoots
Step 2: Planting
- Fill the grow bag about one-third full with compost
- Place 3–4 seed potatoes on the compost, shoots pointing upward, evenly spaced
- Cover with another 10–15cm of compost
- Water well until water runs from the drainage holes
- Place the bag in a sunny position
Step 3: Earthing Up
As the shoots grow and emerge above the compost, add more compost to cover them — leaving just the top few centimetres of foliage showing. This is called ‘earthing up’ and it’s crucial: potatoes form along the buried stem, so more buried stem means more potatoes. Repeat this process 2–3 times as the shoots continue to grow, gradually filling the bag to near the top.
Step 4: Watering and Feeding
Potatoes in bags need regular watering — the compost dries out much faster than open ground. Check daily in warm weather and water whenever the top 5cm of compost feels dry. Don’t let the compost dry out completely or you’ll get small, cracked tubers.
Once the plants start flowering (or would be flowering — some varieties don’t produce obvious flowers), start feeding weekly with a diluted liquid tomato feed. The high potassium content promotes tuber development. The Gardeners’ World container potato guide covers feeding schedules in detail.
Step 5: Harvesting
For first earlies, harvest when the flowers open (or about 10 weeks after planting). For second earlies and maincrops, wait until the foliage starts to yellow and die back.
The beauty of bags is easy harvesting: simply tip the bag onto a tarpaulin or large sheet and pick out the potatoes. It’s immensely satisfying — like a treasure hunt. Expect 1–2.5kg per bag for earlies and 2–4kg for maincrops, depending on the variety and growing conditions.
Common Problems
| Problem | Cause | Solution |
|---|---|---|
| Small potatoes | Too many per bag, or insufficient watering | Max 4 seed potatoes per 40L bag. Water consistently |
| Green potatoes | Exposed to light | Earth up properly. Don’t eat green potatoes — they contain solanine |
| Blight (brown patches on leaves) | Fungal disease, common in wet summers | Grow first earlies (harvested before blight), or blight-resistant varieties like Sarpo Mira |
| Slugs | Slugs tunnel into tubers | Less of an issue in bags than ground-planted. Use organic slug pellets if needed |
| Spindly, weak growth | Insufficient light | Move bags to the sunniest position available (6+ hours direct sun) |
What to Do with the Compost Afterwards
Don’t reuse compost for growing potatoes the following year — this builds up disease. However, the spent compost is excellent as a soil improver for borders and flower beds, or for mixing into your general compost heap. If you grow potatoes every year, you’ll build up a fantastic supply of enriched garden soil as a by-product.
