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Grow Potatoes in Trenches, Mulch, or Containers

Potato growing in mulch
Grow Potatoes in trenches, mulch, or containers. Here potatoes grow in straw mulch.

Potatoes are easy to grow in holes, trenches, under mulch or landscape fabric, or in containers. Grow potatoes in full sun and well-drained soil or mulch.

Plant potatoes when the soil temperature is at least 50°F. Potatoes grow best when the air temperature is between 60 and 65°F.

Grow potatoes from seed potatoes—small tubers grown especially for planting to produce a crop. Keep plants evenly moist as tubers develop and enlarge.

New or baby potatoes (called “earlies”) are harvested early in the season 75 to 90 days after planting. Main-crop or mature potatoes require 135 to 150 days to harvest.

Potato Planting Times:

• The traditional time to plant potatoes is in spring as soon as the soil can be worked, about two to four weeks before the last expected frost. Spring planted potatoes grow best in beds covered with plastic or raised beds that warm quickly. Keep beds covered with compost or straw until plants emerge. Protect newly emerged plants from frost and insects by covering the planting bed with a floating row cover. Remove the cover 3 to 4 weeks after leafy growth appears.

• Potatoes for fall harvest are planted in summer. Plant fall harvest potatoes early enough that tubers can mature before the first frost.

• In mild winter regions, potatoes can be planted in fall or winter whenever the ground is workable.

Protecting Potatoes:

Protect growing potato tubers from light, fluctuations in temperature, pests, and injury by keeping them covered as they grow. Use soil, compost, mulch, hay, straw, or landscape fabric to keep tubers covered. As potatoes grow, tubers push upwards and are easily exposed to light. Tubers exposed to light turn green and contain a chemical called solanine which can be poisonous.

Growing Potatoes in Trenches:

Trench planting is the traditional method for growing potatoes. Dig a trench or hole 4 to 6 inches deep, put the seed potatoes in place one foot apart, and backfill with 2 inches of soil. When the plant grows to 6 inches tall, add soil to cover all but the top leaves; fill the hole or trench as the foliage grows on and continue to hill up loose soil around the plants.

Seed potatoes can be set on the surface of a planting bed and covered with soil; as with trenching, continue to hill up or mound soil above the tubers. At the end of the season, the plants will be covered by a low mound of soil.

Growing Potatoes Beneath Mulch:

Potatoes can be grown across the surface of a planting bed by simply covering seed potatoes with mulch. This method requires no digging.

Loosen a few inches of soil across the planting bed then lay seed potatoes on the soil cut side down about one foot apart. Each seed potato should have two or three eyes. Cover the seed potatoes with one foot of mulch—shredded leaves, leaf mold, or clean hay or straw.

When shoots and leaves have emerged from the mulch and grown about 6 inches, add more mulch—enough to cover all but the top most leaves. Repeat this process. After several weeks, begin to check under the mulch periodically for developing tubers. The mulch should always be several inches thick over the tubers keeping tubers from turning green.

Mulch, unlike soil, is not rich in nutrients so the yield may be less. Feed mulch grown potatoes with fish emulsion— after sprouts emerge and again just before plants flower.

To harvest new or mature potatoes, lift the mulch and take what you need; be sure to recover still growing tubers so that they do not green.

Growing Potatoes Beneath Fabric:

Potatoes can be grown under black landscape fabric with almost no effort. Place seed potatoes on the planting bed one foot apart then place black landscape fabric over the planting bed. The black fabric will exclude light as though the tubers were underground. As plants emerge they will begin to push up the fabric; cut slits in the fabric to allow the plants to grow up. Make sure that as plants grow, tubers are kept under the fabric and not exposed to sunlight. To harvest potatoes enlarge the slit or roll back the fabric to expose the tubers.

Growing Potatoes in Containers:

Potatoes are easy to grow in large containers: bushel baskets, wooden or plastic barrels, plastic or metal trash cans, wire cages, and even heavy-duty plastic garbage bags. A container for potato growing should be at least 2½ to 3 feet tall and 3 feet across with holes for drainage in the bottom and sides. A container 2 feet across can support four plants.

Place a few inches of soil at the bottom of the container then lay seed potatoes on the soil and cover them with a few inches of soil or aged compost. Once the plant has begun to grow and reached about 6 inches tall, add soil, compost, or straw mulch to cover all but 3 inches of the plant—just a few leaves poking through the soil. Again, let the foliage grow another 6 inches and repeat. Continue this process until the container is filled. If you use heavy-duty garbage bag, simply roll the bag up until it is filled.

When harvest time comes, turn the container on its side and let the potatoes spill out.

When to Harvest Potatoes:

New potatoes (baby potatoes) are ready for harvest when the potato plant begins blooming. New potatoes are sweet, moist, and tender because sugars in the tubers have not yet begun to convert to starch.

Potatoes tubers are fully mature when the potato vine begins to die back. Cut the vines back to soil level two weeks before you want to harvest.

More tips: How to Grow Potatoes.

 

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6 Comments

  1. I’m growing potatoes in wire cages. It’s about 2′ by 3′. I planted all of the seed potatoes I got in the bag, about 25. I guess I should thin them out? Will they be overcrowded and produce less with so many plants? Should I cut them down to 6 or 8?

    • Yes, you have overplanted; one or two seed potatoes would be sufficient for the size cage you are using. Remove some of the seed potatoes and replant them in another cage or in the garden. Crowding will result in small tubers.

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