It happens every spring. As I go through the pantry to organise empty canning jars, I discover a few sprouting potatoes searching for light in drawers or shoe boxes (my favourite storage containers for potatoes). Those that are so far gone that the brittle shoots crumble in my hands get composted, while better looking sprouting potatoes get planted in containers kept indoors until freezing weather passes. These plants produce a very early crop of tender new potatoes.
Note that this is but one method for growing potatoes, best suited to the special situation of having seriously sprouted potatoes on hand a month before they can possibly be planted. If you’re just getting to know garden potatoes, please review How to Grow the Best Potatoes in the World. There is more than one way to grow potatoes!
Any potatoes that show bulging sprouts have broken dormancy, and are actively converting their starches into sugars and other nutrients needed for growth. Early-maturing potatoes tend to have shorter dormancy periods than late maturing varieties. You can eat slightly sprouted potatoes as long as they feel firm and you remove the sprouts first. Just like green potato skin, potato sprouts contain solanine, a bitter compound that can make you sick.
Tubers that have just broken dormancy, like those in the photo at the top of the page can simply be placed in a well-lit place to green up. A few weeks of greening up, or chitting, triggers the production of more solanine, which deters feeding by voles and other critters and delays rotting. Chitting or greening up potatoes is standard practice with my main crop, but seriously sprouted potatoes demand immediate attention. If they’ve started to shrivel, sprouted potatoes are fair game for my earliest planting, which is started indoors.
A sprouting potato is a marvel of reproductive botany. With a hand-held magnifying glass, you can see numerous rounded root buds near the base of any sprout, with pointed leaf buds at every stem tip. In tissue culture work, tiny bits of potato meristem (growing tip of a sprout) have been used to grow plants that produced normally. Since I grow only a few plants this way, I root the fittest potato sprouts and compost the rest. They root quickly! The white roots grew on the cutting at right after only three days in moist soil.
Containers for Sprouted Potatoes
Indoor growing space gets tight in spring at my house, yet potatoes grow best in roomy containers with somewhat breathable root space. My cheap solution is to root sprouting potatoes in double-thick paper lunch bags filled with potting soil. By the time the plants are set out in the garden, the bags are ready to decompose.
One of the newer products being offered by garden suppliers are potato grow bags made out of porous landscape fabric. Also called patio potato bags, these reusable pots can get pricey, but if you can sew at all you can make your own. This Instructables video shows how to cut and sew several in less than an hour.
I don’t recommend growing your main crop of potatoes in potato bags or any other containers unless you live in a cool climate, because warm roots (unavoidable in containers) cause potatoes to stop setting tubers. This is not much of an issue when you’re pushing the season to accommodate seriously sprouted potatoes in early spring. Besides, as any gardener knows who has lifted and moved volunteer plants, potatoes are infinitely transplantable.
Rooting Sprouting Potatoes
Most of the sprouted potatoes I must deal with came from my garden, and gardeners are often cautioned to start with certified disease-free seed potatoes because replanting your own can be an invitation to disease. I agree, but not when it comes to my extra-early crop. Besides, if there is any question about the health of the mother potato, you can carefully remove the stems and root them in moist potting soil. Propagating potatoes this way greatly reduces the risk of transmitting viral diseases, and eliminates having a chunk of rotting potato in your pot.
My little fingerling potatoes seem to benefit from being rooted with a bit of potato intact, but I plant very robust sprouts with no bit of potato attached. And, though I don’t think twice about planting small chitted potatoes whole when planting my main crop, I try to limit how much mother potato goes into a container to reduce risk of root rots.
Sprouted potatoes can be ugly or beautiful, depending on whether or not you find a place for them in your garden, or perhaps in containers on your deck or patio. Tender new potatoes grown from sprouted spuds make a great prelude to your main crop, and prove that there are many ways to grow great potatoes.
By Barbara Pleasant