What sort of potato grows best in what sort of pot? Well, there are no hard and fast rules, but varieties have their own peculiarities.
Don't use containers deeper than about 12 inches. The compost will probably go stagnant.
Most potatoes produce their tubers in a layer about 6 inches deep, with the seed tuber at the bottom of the layer.
OPTION 1: 3-GALLON BUCKETS
Varieties where the yield justifies a full 3 gallons of compost are usually big maincrop plants, for example: PICASSO, MARIS PIPER, GOLDEN WONDER, ROOSTER, BRITISH QUEEN, PINK FIR APPLE (in a good year), SALAD BLUE, SHETLAND BLACK, NADINE, SARPO MIRA or AXONA. Expect around 3lb tubers per pot. On hot days you must water very heavily.
I have found these containers give low yields for HIGHLAND BURGUNDY RED, RED DUKE OF YORK, ANYA, HARLEQUIN, MIMI, and most earlies.
One other arrangement you can try with really big plants is to use a bottomless pot: remove a six inch diameter hole from the bottom of the bucket using a jigsaw (do not do this unless you are competent with tools!). The yields are 10-15% higher, and you don't need to water quite so often once the plants are established. The plants get aditional moisture from the ground by sending down a few roots. All of the tubers develop inside the container.
OPTION 2: TRAYS (2½ gallon)
I've found MARIS PIPER loves this arrangement (I have had 6lbs tubers from 4 seed). It needs very heavy watering so you won't be able to go away on holiday! Generally I use 4 seed, one in each corner, but if the seed is really tiny I might use six. Heap the compost up well in the centre.
PICASSO is excellent like this (I've had 4lb), also SALAD BLUE, but the plants are a bit big and may need support. Other suitable spuds: HIGHLAND BURGUNDY RED, SHETLAND BLACK, MIMI, DUNLUCE ELITE, RED DUKE OF YORK, ANYA, HARLEQUIN, ROOSTER. Most earlies also do well in trays.
Really big plants, however, do better with a bit more depth to the compost.
OPTION 3: FLORIST'S BUCKETS
One other container worth mentioning is the florist's bucket. These are black containers used for delivering flowers to shops; they have a capacity of about 2 gallons and no handle. They are particularly good for earlies, where the yield is lower than for maincrops - say 2lb per container. Make the shop owner an offer; otherwise he'll probably have to dump them. 5 for £1, perhaps?
Suitable varieties for these containers: ANYA, SWIFT, RED DUKE OF YORK, HARLEQUIN, EDZELL BLUE, ROCKET, MAYAN GOLD/TWILIGHT. Avoid large-haulm varieties like Salad Blue, Golden Wonder, Majestic. They'll grow OK, but in a wind they will blow over, especially swhen they need watering. This becomes tiresome when it happens every day.
So- cancel your summer holiday, and start growing spuds in containers. We grow about 50 containers-worth, plus about the same number in the ground. The containers enable us to double our yield and try many different sorts. You will become aware of a world of different flavours.
If, like us, you decide to grow a serious quantity, keep newly sown potatoes further from the house; bring the containers nearer to the watering point as they develop. This will minimise walking distances when watering.
Wash and dry them straight away, and they will store (if kept cold and dark) until new potatoes come again.
Potatoes of this quality sell for around £2 per punnet, if you can get them.