You can buy seed potatoes and many recommend this process. I have never done so. Those who do claim that the potatoes sold in supermarkets are treated with a chemical to inhibit sprouting. It is also said that even though you may buy potatoes that have some eyes on them, and even some that are sprouting, they are still possibly treated … but sprouting anyway. It has also been said that using potatoes that have been treated will slow the growth of the plants and produce less potatoes.
I don’t know. I can’t prove it but I want to test this theory and hopefully I’ll do it this summer (2013). I want to buy some seed potatoes and grow them on in a barrel doing the same with some grocery store bought potatoes and treat both the same throughout the test. I’ll post the results here.
**** I did test this theory this year, 2013, and here is what I found. Now this was not a “scientific” experiment and the actual growing conditions were not scientifically controlled to be exactly the same. I planted three barrels with potatoes I got at the grocery store, and one with seed potatoes. The barrel with the seed potatoes produced a harvest at least three times that of the other barrels. All conditions were basically the same. I used the same soil, a mix of compost and garden soil with some old horse manure I had. I watered them all equally, at the same time, and they were all exposed to sun and rain the same amount. I was surprised by this, although I suppose I should not have been. My advice … purchase seed potatoes or save some of your own from year to year. I’ll never bother with store bought potatoes again. Another possibility may be from farmers markets where the local farmer does not treat the potatoes to slow their eye growth. I will re-write this post at some point in the future. ****
All potatoes will have eyes or sprouts on them although not all will actually show the beginning of their growth. The eye looks like a small root beginning to grow out of the potato. It will be a sand color and as it grows it will turn green as it becomes a leaf. You have probably seen this happen to your potatoes that you have in your home, at some point in time.
Seed potatoes are sold, often as organic, as treatment free so they will readily grow into potato plants. Growers will certify that they have not been treated. Potatoes from your grocer will not say if they have been treated or not. I have to wonder if the high end grocers sell the treated potatoes while the cheaper or discount grocers do not. It would be an added cost so the discount grocers may provide untreated potatoes.
Some also recommend to use the whole potato and select smaller potatoes with only one or two eyes. I cut my potatoes up into pieces that have one or two eyes. I’ll cut these up as small as a golf ball, although I guess they are usually about twice that size, and larger. I’ve never had disastrous results with these small sizes but if I had to make a statement I’d go with the larger size producing better results. So, I’ll recommend keeping the size to about that of two golf balls to one tennis ball size for best results. You can use whole, uncut potatoes if you wish. There is no problem with that. If you do cut the potatoes into pieces with one or two eyes, let them sit out, preferably in the sun, for a couple of days to “heal”. This means to let the cut surface of the potato dry up. It becomes almost leathery. This will reduce the number of your seed potatoes that rot after being planted.
That is it about seed potatoes. Buy them, or use your own to make your seed potatoes.