I recently had to order some more seed potatoes (these are hard to find) as my batch from last year was lost in the earth due to the intensely wet summer we had. I lost all of my root vegetables in fact, they just turned to mush in the ground. I have a penchant for the Blue Aidorondack variety though there are other purple hued potatoes on the market.
When spuds arrive you will usually get what really just looks like whole potatoes. It was so tempting not to eat them, but for the growth and betterment, they must be planted. It is estimated that for each seed potato piece that you plant, you can gain 10 pounds of new potatoes from just that one seed.
What is a "seed?" Well, when you let a potato sit too long it starts to sprout "eyes" when left in a cool, dark place these eyes will pop and start growing vine-y type of shoots. This is a good thing because for each "eye" that is essentially your "seed." If a potato is covered with eyes, you cut it up and plant each piece as a seed effectively gaining up to 10 or more pounds of yield per cut piece. (usually at least 2-3 per well sprouted spud).
Once your time is up, you can plant. There are so many methods to planting potatoes, and everyone will tell you their method is best. These potatoes are no exception. I have had tremendous success planting these directly in well worked ground, but, in a wet year you will loose them all as root crops rot in the ground when it is too wet for too long.
This year I am using a grow sack, you can just as easily use a plastic storage tub with some drainage holes drilled into the bottom, or even a plastic trashcan with drainage holes.
Simply fill your container with a healthy grow medium (I bought a bag of composted cow manure for $5, and no, there is NO odor to it at all). Start by filling your container only about 1/2 to 3/4 full as you will add more dirt/compost after the shoots of green start to show up.
You will know that it is time to check on and dig your potatoes when, nearing the end of summer your green leafy vines start to yellow and die back. At this point you can gently dig down with your hands and feel for the spuds, if you feel fully formed spuds/potatoes, just lay down a tarp and dump out your container to collect the potatoes.
You need to let the potatoes "cure" for a few days in a cool, dry place. This will allow for better and longer storage time. After that, enjoy your bounty!
** Note** I purchased my seed potatoes from Pinetree Garden Seeds this year, their customer service is top notch and they have beautiful catalogs for free as well.