We’ve begun the season for planting Irish potatoes in Louisiana, with prime planting days from now until the end of February, says LSU AgCenter vegetable expert Kiki Fontenot.
The best way to plant potatoes is to dig a shallow trench about 4 inches deep, place sections of seed potatoes about 12 inches apart and then cover the trench.
“People often cut seed potatoes too small, and they can rot if the soil stays wet too long,” Fontenot says. “Cut baking-size potatoes into quarters and small potatoes in half — about the size of a silver dollar. The bigger the piece, the better.” Each piece should have at least one eye, which is the sprout that grows into a plant.
Potato plants need plenty of room.
“The bushes grow 2½ to 3 feet tall and look perfectly manicured like mushrooms,” she says. “The only thing you really need to do to get a good potato crop is to water and fertilize.”
Preplant fertilizer, such as a 13-13-13, followed by another light application when the plants begin to bloom are all that are needed.
A light frost shouldn’t hurt the plants. And even with a freeze, only the tops of the plants will be affected, which may delay harvest. If rainfall is sparse, especially during bloom when the tubers begin to form, an extra watering or two will help assure larger potatoes.
When the tubers begin to grow, some may peek out of the soil. The sun will cause the skin to turn green and produce alkaloids, which can cause stomach distress if they’re eaten. To prevent this, mound soil around the bottoms of the plants or lay down a heavy mulch, like leaves. In raised beds or containers, you can add bagged soil to the planter, Fontenot says.
The potatoes are ready to dig about 90 to 110 days after planting.
If long-term rain threatens, it’s best to dig the potatoes when they’re small rather than allow them to remain in saturated soil where they may rot.
Recommended varieties for Louisiana are Red LaSoda, a red-skinned potato, and Kennebec, a brown-skinned tuber. Others include Golden Yukon, which has a yellow flesh, and Purple Majesty, which has a purple skin and flesh. Both do well in Louisiana.
“Potatoes are easy to grow,” Fontenot says. “I’ve never had a problem them.”
Got a gardening question? Write to GardenNews@agcenter.lsu.edu.