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Growing Potatoes in the Home Garden

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Overview:

Potatoes are one of those mystery crops that develop out of sight, underground. You never really know how you’re doing until you harvest - and then it’s too late to change things. The potatoes we eat are starchy tubers that grow under ground, swelling and getting larger as the top half of the plant matures. The humble potato can be very finicky to grow, because of pest and disease problems.

Potatoes are relatively inexpensive to purchase, but growing your own is the best way to ensure they will not have been exposed to excessive chemicals to offset their growing problems. Plus you'll have a lot more varieties to choose from. Oval baking potatoes and red potatoes have dominated the market, but there are actually over 1,000 different varieties of potatoes available for growing. The texture of potatoes, even more so than the flavor, is very variable from variety to variety.

Latin Name:

Solanum tuberosum

Common Name: Potato

Hardiness Zones:

Since potatoes are grown and harvested as an annual, USDA Hardiness Zones do not apply.

Exposure

To keep the top growth growing and feeding the tubers, potatoes should be planted in full sun to partial shade

Mature Size:

The plants grow a couple of feet tall, but the size of the actual potatoes will vary widely with variety, from large baking types to tiny fingerlings.

Harvesting:

Days to Harvest: 2 - 4 Months.

The entire crop is ready to harvest once the tops of the plants die off. You can leave the potatoes in the ground for a few weeks longer, as long as the ground is not wet.

New potatoes are small, immature potatoes. You can harvest a few of these without harm to the plant, once the plant reaches about a foot in height. Gently feel around in the soil near the plant and lift them out.

Harvest carefully, by hand or with a shovel. Turn the soil over and search through for treasure. The tubers can branch out and digging in with a fork is a sure fire way of stabbing a potato or two.

Pest & Diseases:

Beetles & aphids will defoliate the plants. Monitor early in the season, before they become a major problem. The Colorado potato beetle larva, pictured in the 2nd photo, is easy to spot. Also check for egg masses on the undersides of leaves. (Photo 3.)

Thin, red wire worms attack underground. I wish I had a better solution, but rotating crops is the only thing that has worked for me.

A low soil pH will help control scab, a common potato disease that can look like a raised corky area or sunken holes.

Late blight, the cause of the Irish potato famine, turns the foliage black, then moldy. Burn the foliage. The potatoes can still be harvested, but you should wait several weeks. Use certified disease-resistant seed potatoes.

Three Cultural Practices to Lessen Potato Growing Problems:

  1. Buy certified disease-free seed potatoes. Planting potatoes from the grocery store is a gamble. Besides the disease problem, potatoes, like many produce isle vegetables, are often treated with a growth inhibitor to keep them from sprouting.

  2. Grow your potatoes in soil with a pH between 5.0 and 6.0. Potatoes grown in soils with a higher pH seem prone to a disease called 'scab', which produces rough spots on the potato. Adding compost or peat will help.

  3. Don't plant your potatoes where tomatoes or eggplant were grown the year before. These are in the family as potatoes and can attract similar pests and problems.

Suggested Varieties:

  • Irish Cobbler - Early season potato that can be planted as soon as the ground dries.
  • Kennebec & Katahdin - Good for storing.
  • French Fingerling - Long, slender red-skinned potatoes that don’t need peeling.
  • All Blue - Fun to surprise people with. Good keeper. (Photo 3)

Growing Tips:

What to Plant: Seed potatoes aren’t really seeds at all. They are full-size potatoes that are allowed to start producing shoots in the potato eyes. You’ve probably seen this happen when you’ve stored potatoes in the kitchen for too long.

Seed potatoes can be planted whole or cut into pieces, with each piece containing an eye or two (or three). Because potatoes can rot if the soil is too cool or wet, many gardeners prefer to allow the cut pieces to callus over, by leaving them exposed overnight. You can also purchase a powdered fungicide for dusting onto the pieces, to avoid rotting

Cold climate gardeners plant potatoes in mid to late spring. Warm climates do best planting in either late summer or late winter, so the plants aren’t trying to grow during the hottest months.

If you’d like to extend your potato growing season, choose an early variety and a later, main season variety.

How to Plant: Choose a sunny spot with well draining, loose soil, so that the roots and tubers can develop. .

  • Trench Method: A traditional potato planting method involves digging a shallow trench, about 6" deep and placing the seed potatoes in the trench, eyes facing up. You then cover the potatoes with a couple of inches of soil. As the potato plant grows, soil is continually hilled up along the sides of the plants. This keeps the soil around the developing tubers loose and keeps the surface tubers from being exposed to sunlight, which will turn them green and somewhat toxic. Hill soil whenever the plants reach about 4-6" in height. You can stop tilling when the plants begin to flower.

  • Scatter Method: Some gardeners prefer to simply lay the seed potatoes right on the soil and then cover them with a few inches of mulch. You can continue laying mulch as the plants grow. If you have a rodent problem, this method is probably not your best choice.

  • Container Method: The container method makes hilling easy and takes up less space. Plant your seed potatoes in the bottom of a tall container, like a clean garbage can or whiskey barrel. Put about 6" of soil in the bottom first, then spread out your seed potatoes. Keep adding soil as the plants get taller. I’ve tried this several times using just a bale of peat and it worked quit well.

Maintenance: Potatoes don’t like a particularly rich soil. If you have a good amount of organic matter in the soil and the pH is good, the potatoes should be happy. What they do rely on is a steady water supply. Water them at least an inch a week.

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