How to Grow Potatoes in the Ground and in Bags

Start with seed potatoes

Buy certified seed potatoes from a garden store, not potatoes from the grocery aisle. Certified seed is checked for disease, while grocery potatoes can carry rot and viruses that ruin a crop, and many are sprayed to stop sprouting.

About 2 to 3 weeks before planting, sprout them first, a step called chitting. Set the seed potatoes in an egg carton in a cool, bright spot until short, stubby sprouts form. Sprouted pieces come up faster and give you a head start.

• Buy certified seed potatoes, not grocery ones.
• Chit them 2 to 3 weeks before planting in a bright, cool room.
• Cut large seed potatoes so each piece has 2 to 3 sprouts, then let the cuts dry 1 to 2 days.

Plant deep and give them room

Plant seed potatoes 4 inches deep with the sprouts pointing up. Space the pieces 12 inches apart in the row, and keep rows 36 inches apart so you have soil to mound up later and room to walk.

Wait until the soil has warmed to about 50 degrees Fahrenheit. Cold, wet soil rots the seed before it can grow.

• Plant 4 inches deep, sprouts up.
• Space 12 inches apart in the row.
• Keep rows 36 inches apart.
• Wait for soil near 50 degrees Fahrenheit.

Hill as they grow

When the plants reach about 8 inches tall, mound soil up around the stems and leave just the top few inches of leaves showing. This is called hilling. Repeat every 2 to 3 weeks as they grow.

Hilling matters because tubers form along the buried stem, so more covered stem means more potatoes. It also keeps tubers in the dark. Any potato that pokes into the light turns green, and green parts are bitter and not safe to eat, so cover them up.

Grow them in a bag

Short on space? A 10 gallon grow bag holds 1 to 2 seed potatoes and fits on a patio or balcony. Start with about 4 inches of soil, set the seed potatoes on top, and cover with a few inches more.

As the plants grow, add soil the same way you hill a row until the bag is nearly full. Water often, since bags dry out faster than the ground, and aim to keep the soil damp but not soggy.

• Use a 10 gallon bag for 1 to 2 seed potatoes.
• Add soil as plants grow, like hilling a row.
• Check water daily in hot weather since bags dry fast.

Harvest and cure

Most potatoes are ready about 90 days after planting, once the leaves and stems yellow and die back. For new potatoes, you can dig a few early while the plants still flower.

Dig on a dry day and brush off the dirt, but do not wash them yet. Cure the potatoes in a single layer in a cool, dark, airy spot for 1 to 2 weeks so the skins toughen. Then store them in the dark, where a good crop keeps for months.

• Harvest around 90 days, after the tops die back.
• Dig on a dry day and do not wash them.
• Cure 1 to 2 weeks in a cool, dark, airy spot before storing.