To grow potatoes (Solanum tuberosum) in a container, plant chitted seed potatoes in a few inches of soil in a large pot, then keep adding soil around the stems as they grow so tubers form along the buried stem. Water steadily, feed once the plants flower, and harvest by tipping the whole pot out onto a tarp. A 15 gallon / 57 L container with drainage holes, full sun, and steady moisture will give a worthwhile crop from a balcony or paved yard with no open ground at all.
Potatoes were the first thing I ever grew in a pot, years before I had a proper plot. A single seed potato in an old builder’s bucket on a south-facing step gave me a meal of new potatoes that tasted far better than the work involved. The pot does something the open ground cannot. You control the soil, you control the water, and at harvest you tip the whole thing out instead of digging blind with a fork and spearing half the crop.
Step-by-step: growing potatoes in a container
Why a pot suits potatoes so well
Potatoes are one of the easiest crops to grow in a container, which surprises people who think of them as a field crop that needs acres. The plant does not care whether its roots are in open ground or in a fabric bag, so long as it has loose soil, sun, and water. A container gives you all three in a spot where you could never dig a bed.
The pot warms faster than the ground in spring. Soil in a black container sitting in the sun heats up within days of a warm spell, while open ground stays cold and wet for weeks longer in a zone 5 garden. That early warmth lets you plant a couple of weeks ahead of the ground crop and get new potatoes on the table sooner.
Harvest is the real advantage. A potato dug from open ground means forking through the soil and hoping you find them all without slicing any. A container crop comes out clean. You tip the pot onto a tarp, run your hands through the loose mix, and lift out every tuber whole. Children love this part, and it turns harvest from a chore into the best day of the season.
Choosing the right container
Size matters more than anything else with container potatoes. A small pot gives a small crop, full stop. The roots and tubers need volume, and a cramped plant in a 5 gallon / 19 L pot puts up plenty of leaf and almost no potato. A potato plant needs roughly 2.5 gallons / 9.5 L of soil volume to crop well, which is why 2 to 3 seed potatoes per 15 gallon / 57 L pot gives the best balance (University of Minnesota Extension).
Drainage is the second rule. The container must have holes in the base so excess water runs out. Potatoes sitting in soggy soil rot rather than swell, and a sealed pot with no drainage is the quickest way to lose a crop. If you reuse an old bucket, drill several holes in the bottom before you fill it.
Fabric grow bags have become my favourite for potatoes. They breathe, which keeps the roots cooler and stops the soil going sour, and they drain freely through the cloth. At the end of the season they store flat in a drawer, which matters on a small balcony. A rigid pot or a half barrel works just as well, only with more bulk to store over winter.
Container sizes and yield
| Container | Volume | Seed potatoes | Expected yield (early) / (maincrop) | Hilling depth |
|---|---|---|---|---|
| Small bucket | 5 gal / 19 L | 1 | 0.5-1 lb / 0.2-0.5 kg | 8-10 in / 20-25 cm |
| Standard grow bag | 10 gal / 38 L | 1-2 | 1-2 lb / 0.5-1 kg | 12 in / 30 cm |
| Large grow bag | 15 gal / 57 L | 2-3 | 2-3 lb / 0.9-1.4 kg (early), 3-4 lb / 1.4-1.8 kg (maincrop) | 18-20 in / 45-50 cm |
| Half whiskey barrel | 25 gal / 95 L | 3-4 | 3-5 lb / 1.4-2.3 kg (early), 5-7 lb / 2.3-3.2 kg (maincrop) | 22-24 in / 55-60 cm |
| Large dustbin or potato barrel | 30 gal / 114 L | 4-5 | 4-6 lb / 1.8-2.7 kg (early), 6-9 lb / 2.7-4 kg (maincrop) | 24-28 in / 60-70 cm |
The first year I grew potatoes in pots on the trial patio, I planted six seed potatoes into a single fifteen-gallon barrel because it looked half empty. The plants came up thick and green, and I congratulated myself. At harvest I tipped out a tangle of stems and a sad scatter of marble-sized tubers. The next year I dropped it to three seed potatoes in the same barrel, hilled them properly, and pulled out a respectable meal of full-sized potatoes from each pot. Fewer plants, more soil per plant, and a much better crop.
The hilling that makes the crop
Hilling is the single technique that separates a heavy container crop from a poor one. Potatoes form their tubers along the underground part of the stem, not just at the original seed potato. The more stem you bury, the more length there is for tubers to form along, and the bigger the harvest.
Start the container only part full, with the seed potatoes covered by 4 inches / 10 cm of soil. When the stems reach 8 inches / 20 cm tall, add more mix around them so only the top few inches of leaves show. Keep repeating this every 2 weeks as the plants grow, topping the pot up in stages until the soil reaches the rim. By the time you stop, you have buried 18 to 24 inches / 45 to 60 cm of stem, all of it carrying tubers.
Do not bury the leaves completely each time. The plant needs green foliage above the soil to photosynthesise and feed the growing crop. Cover the lower part of the stem and leave the top growth exposed. Done in stages through the season, hilling roughly doubles what a single uncovered seed potato would yield.
Watering and feeding
A container of potatoes drinks far more than people expect. The pot is packed with foliage by midsummer, all of it transpiring water on a hot day, and the soil dries from the surface down within hours. A pot that dries out at the wrong moment gives a small, cracked, knobbly crop, since the tubers swell unevenly when water is on and off. A 15 gallon / 57 L container of potatoes in full leaf can use 1 to 2 gallons / 4 to 8 L of water on a hot July day.
Check the moisture daily in warm weather. Push a finger an inch into the soil, and if it feels dry, water until it runs from the drainage holes. The aim is steady, even moisture, never a swamp and never bone dry. Self-watering containers with a reservoir take some of the daily pressure off, which helps anyone away at work all day.
Feeding starts once the plants flower, which is the sign that tubers are forming below. A liquid tomato feed every 2 weeks supplies the potassium that drives tuber growth. The potting mix holds some nutrients at planting, but a heavy crop in a confined pot exhausts that supply, so the extra feed pays off at harvest.
Choosing varieties for pots
Early varieties suit containers best. They crop fastest, often 10 to 12 weeks from planting, and they get out of the pot before the worst summer heat and before blight arrives in a damp year. First and second earlies such as ‘Charlotte’ (a firm, waxy salad type), ‘Maris Bard’ (a heavy-cropping white), or ‘Red Duke of York’ (a red-skinned early) all do well in pots and give those prized new potatoes.
Maincrop varieties grow in containers too, and they store better for winter, but they need a bigger pot and a longer season. ‘Maris Piper’ and ‘Desiree’ are reliable maincrop choices that store well through winter. They sit in the container for 16 weeks or more, which ties up the space and the water for most of the summer. If your main aim is a quick, tasty crop from a small space, stick with earlies and replant for a second go.
Always start with certified seed potatoes from a garden centre rather than potatoes from the kitchen. Supermarket potatoes are often treated to stop them sprouting and may carry diseases that build up in the soil. Certified seed is grown to be virus free and gives a healthier, heavier crop for the small cost.
Common problems and fixes
Green tubers are the most common complaint. A potato exposed to light turns green and produces a bitter, mildly toxic compound called solanine that makes it inedible. The fix is the same as the hilling that builds the crop. Keep the tubers covered with soil so no light reaches them, and at harvest store the potatoes in the dark.
Sparse, leafy plants with few tubers usually mean too many seed potatoes crammed into one pot, or too little sun. Thin to two or three per fifteen-gallon container, and move the pot to the brightest spot you have. Potatoes need at least 6 hours of direct sun to crop well, and they sulk in shade.
Blight (Phytophthora infestans) can strike in a warm, wet summer, blackening the leaves and rotting the tubers. There is no cure once it takes hold. Cut off and bin the foliage at the first dark blotches, and harvest the tubers straight away before the rot spreads down the stems. Growing earlies that finish before blight season is the simplest way to dodge it altogether, which is another reason to favour first and second earlies in containers.