Growing potatoes in bags is a space-saving way to get a great harvest on UK patios and balconies. Bags warm up fast in spring, reduce slug damage, and make harvesting simple—just tip them out.
Best varieties for bags
- First earlies: Swift, Rocket, Pentland Javelin (fast and reliable)
- Second earlies: Charlotte, Maris Peer (great for salads)
- Mains: Maris Piper (bigger bag, more feed and water)
What you need
- Fabric potato grow bags (35–50L) with drainage
- Peat-free multi-purpose compost mixed with 20–30% perlite
- Seed potatoes (chitted)
- Organic potato fertiliser (high in potassium)
Planting step-by-step
- Fold bag sides down and add 10–15cm compost.
- Place 2–3 chitted seed potatoes, eyes up, evenly spaced.
- Cover with 10cm compost; water well.
- As shoots reach 10–15cm, earth up by adding compost to cover stems. Repeat until near the top.
Watering & feeding
In warm weather, water daily or every other day. Compost in bags dries quickly—aim for evenly moist, not soggy. Feed every 2–3 weeks with a balanced liquid fertiliser, then switch to high-potash feed when plants flower.
Position & frost protection
Place bags in full sun (6+ hours). In March/April, protect foliage from late frosts with fleece or move bags to a sheltered spot overnight.
Harvesting
- First earlies: 10–12 weeks after planting; harvest when flowering begins.
- Second earlies: 13–15 weeks.
- Maincrop: 16–20+ weeks; wait for foliage to yellow and die back.
Common problems & fixes
| Issue | Likely cause | Fix |
|---|---|---|
| Small tubers | Underfeeding or low light | Increase feed; move to sunnier spot |
| Green potatoes | Exposed to light | Earth up to keep tubers covered |
| Scab | Dry compost during tuber set | Keep evenly moist, especially after flowering |
Tip: Reuse bag compost for flowers, not next year’s potatoes (helps reduce disease risk).
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