Sprouting potatoes? What to do.

Why grow your own potatoes? Well for one thing, potatoes are one of those vegies that are good to eat organic and buying them organic can be expensive. They are a good use of garden space as a single plant can yield up to five pounds of potatoes. Also, they're fun to grow. This article will tell you how you can turn that scary tangle of sprouting potatoes under your sink, into a meal (or ten!).

Timing: Count backwards from when you wish to harvest your potatoes. Most varieties need between 17 and 19 weeks from planting to harvest. Add another two weeks for “chitting”. Chitting is a way to help the potatoes store up solar energy which makes them more likely to produce a big crop. Exposure to indirect sun hardens the sprouts so they are less likely to break. Also, the green in their skins is bitter and discourages pests from eating your seed potatoes in the ground.

This large potato was cut and allowed to dry on the exposed side before planting.

Sprout your potatoes: Potatoes must go through a natural dormancy before they can sprout again. This can be anywhere from four to six months. UNlike most crops, they are not sensitive to day-length but have an internal timing that can only be altered slightly to suit the farmer's planting cycles. If you wish to delay sprouting, keep potatoes in a cool, dry storage area. If you wish to hasten their sprouting, increase the temperature and moisture of their storage place. Layering them in damp leaves, in a tub kept in a heated part of your house will do the trick. The ideal sprout-length is about ¾ of an inch (10-15 mm). The longer they become, the more likely they are to break when you plant them.

If your potatoes have long, hairy sprouts: If your potatoes already have extensive sprouts, and the sturdy central sprout has many small root-hairs coming off the sides, it's important that you remove those, otherwise you'll get many tiny potatoes instead of a few large ones. These smaller side-sprouts also hasten the dehydration of the potato and weaken its ability to thrive. You can rub off the rootlets with your bare hands, they snap off easily. Multiple, thick sprouts are fine; just get rid of the fine hairs.

Potatoes on left ave too many rootlets. Ones on right have been stripped and are ready for planting.

Best size for seed potatoes: The optimal size for seed-potatoes is the size of a hen's egg. If you have larger potatoes, cut them so they have at least three “eyes” and sufficient flesh. Don't let the freshly-cut sides of potatoes touch each other as this may cause them to rot. (Some browning or blackening is normal for potatoes as they "skin over".) 
 

These are a good size for planting. Note the greenish hue from "chitting".

Chitting your potatoes: You can chit potatoes in your house near a window, or on a covered porch, or in a greenhouse (under a table). Don't put them in direct sunlight and, if there's danger of frost, cover them with a towel or cloth at night or bring them inside. After they have "greened up' a bit, and any cut parts have sealed over, they are ready to plant. 
 

Here are potatoes on a covered porch where they get indirect light.

Green potatoes are mildly poisonous so don't eat them after chitting.

If you have chitted your potatoes and its still too early to plant (the ground is too soggy or there's still snow on the ground) you can store them in a cardboard box or plastic tub, layered between leaves from last fall. You can also use straw. Or follow this link to an innovative way to extend the growing season of your potatoes. Link. We haven't tried this but it seems like it would work.

Some of our 2009 harvest, with seed potatoes stored in a paper sack (on the right).

How many potatoes should you plant? Depending on the variety, you can get five or more pounds of potatoes for each one you plant. You'll need about a foot between each plant in your garden and potatoes like lots of sun and loose, sandy soil. 

Links to our other potato blogs, go to:

Do I need to buy seed potatoes?

Can I Speed Up Potato Sprouting?

"Chitting" Potatoes
How to Plant Potatoes 
Planting Potatoes in Clay Soil