I live in Upstate New York and planted potatoes very late in the season. Some of the potatoes have sprouted and others have not. For the one's that did not sprout, I carefully dug up my seed potatoes and they are very mushy. Is this normal and if not what should I do?
I agree with Stormy; part of the problem may be poor drainage. Best and easiest potato crop I ever had was purely by accident. I tossed some old, sprouting potatoes into my composter one May. In July, I noticed potato sprouts growing through the mix of leaves, grass clippings, and vegetable waste from the kitchen. I waited until September and then pulled up the plants along with about three pounds of potatoes; some were scarred by slugs but all were fit to be eaten with a little trimming here and there. I was amazed that the potatoes would grow without actual soil, but they seemed to do just fine.
If you planted late, and some did not sprout, and those that did not sprout are basically rotten, you are probably doing about normal for a late planting and should enjoy, encourage and weed/mulch the ones that DID sprout. In the future, try to plant earlier, and be sure to let cut seed potatoes "cure" before planting. You can't do anything about that for this year.
Cut seed potatoes that are larger than a chicken egg into pieces about 1 inch across or slightly larger. Each piece should have at least one “eye” (the bud where the stem will grow from) -- preferably two eyes. Egg-sized and smaller tubers can be planted whole.
Traditionally, cut seed potato pieces are allowed to cure for a few days to a few weeks before planting. This is because the cut potatoes need high humidity, plenty of oxygen and temperatures between 50 F and 65 F to heal quickly. If you have excellent, well-drained soil that meets those conditions, you can plant the seed pieces without curing. But if conditions are not right, the seed potatoes will rot in the ground.
From: http://www.gardening.cornell.edu/homegardening/scenec6be.html which just happens to be your local land-grant university and extension program. If anyone knows what works in your area, they would be it, and they are happy to help.
I should read these questions more carefully. You are saying that you dug up (gardener in the making for sure!) the seed potatoes that have not sprouted? And they are mushy and kinda slimey? If they were not overwintered then we have a drainage problem. Are the ones that are successfully growing planted shallower or deeper than the ones that have gone mushy? Those seed potatoes are food for the new potato plant and what the plant doesn't need after it has green growth photosynthesizing to make food for itself, what is left of the seed potato will become sorta mushy and not necessary anymore. If the seed potato was larger and had more eyes did you plant them whole or did you cut them up? Some seed potatos are very small and I just plant the entire thing. Otherwise to cut them into 2 or 4 sections is necessary. Gotta see where and what type of soil you are using. Gotta have drainage, great organic matter and consistent (not lots) of water...and fertilizer. A more ACID soil! Check the pH! I had no idea that potatos love acid soil and I've been lucky I guess for decades. There are ways to grow potatos vertically with straw that helps grow more in less room. Fine to start potatoes later as they do not take long to grow. When the tops start dying, it is time to harvest. Even before the tops start dying you can begin to sneak baby potatoes to eat. Truly need lots more information, potatoes are such a cool crop to grow.