How to Grow Potatoes

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The great thing about growing potatoes (Solanum tuberosum) is that they are incredibly easy to grow in just about any space, but there are other benefits to planting potatoes at home as well. For example, you might be surprised to know that just like a homegrown tomato, a homegrown potato tastes wildly better than a store-bought one.

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Potato plants produce massive yields and can even be grown from scraps of grocery store potatoes, making them a wonderfully inexpensive solution for feeding even the largest, hungriest families. This annual root vegetable is very hardy and produces delicate white, purple or yellow flowers near the end of the growing season, sometimes developing poisonous green fruits that look similar to tomatoes.

Best Uses for Potatoes

Potatoes are one of the most versatile vegetables to cook with. They can be eaten fried, baked, boiled, grilled and can even be blended up in soups as a thickening agent. They're not just filling either; potatoes are naturally low-fat and, when cooked with the skin, they are a great source of vitamin C, potassium, folate and antioxidants.

While a lot of people assume that potatoes take up a lot of garden space, the great thing about these vegetables is that they can be grown in so many ways, including some ways that take up hardly any space at all. Potatoes can be grown in typical gardens, raised beds, planter boxes, barrels and even grow bags. The process is the same: You simply keep piling on dirt or mulch as the plants grow to keep the tubers covered and out of the sun.

There are over 4,000 potato varieties, so while russet potatoes may be the most popular variety in America, it's a good idea to buy a number of different varieties until you find a few cultivars with a taste and texture you really love. For example, many people prefer the tender texture and bold flavor of Yukon Gold or the bright color and meaty skin of the All Blue heirloom variety. If you're planting potatoes in a small container, fingerlings might be the best choice with their small size.

While it's possible to start potatoes from kitchen scraps, many are treated with sprout inhibitors that will make growing new plants difficult and will result in minimal yields as well. If potatoes you already bought start sprouting like wild, then it's a great idea to go the DIY route. This happens more often with organic potatoes, especially those bought from local farmers.

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If you're looking to grow potatoes and don't have some that are already sprouting on hand, then you don't want to buy potato seeds because they are unreliable when it comes to growing new potatoes. Instead, you'll want to look for what are called "seed potatoes," which are tubers grown specifically to be replanted.

Only buy certified seed potatoes, which are sold with a blue tag that states the variety, size, class, crop year, grower or shipper and the state agency where they were certified. Most importantly, these certified seed potatoes are guaranteed to be disease-free, minimizing the risk of damage to both the potato crop and the soil, which is a good idea because many potato diseases can cause long-term problems in soil.

How to Grow Potatoes

  • Common Name: Potato
  • Botanical Name: Solanum tuberosum
  • When to Plant: Early spring
  • USDA Zones: Potatoes can be grown in all regions
  • Sun Exposure: Full sun
  • Soil Type: Slightly acidic, loose and high in nutrients
  • When it's in Trouble: Foliage is filled with holes; leaves turn yellow or brown; foliage dies off; potatoes have pitted, scab-like growth
  • When it's Thriving: Has bright-green foliage that continues to grow taller throughout the growing season, eventually growing delicate white, purple or yellow flowers that produce poisonous green fruits shortly before dying off, indicating that it's time to harvest

Starting Potatoes From Seed

Whether you are planting from scraps or seed potatoes, always wait until they have already sprouted. If your potatoes haven't yet sprouted, simply set them on your counter near the window for a week or two until sprouts emerge.

Because each of the potato's eyes can grow into a stem, you don't want too many on any one plant since it can grow too many stems that will compete with one another, leaving you with very few and very small potatoes. This means you should never plant whole potatoes unless they're smaller than a chicken egg. For larger potatoes, wait until the potatoes have sprouted and then use a sharp knife to cut them into small sections at least 1 inch wide with two or three eyes each. Wait at least three days to plant the potatoes, as this allows the cut to callous, making it more resistant to rot and disease.

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Plant the potato pieces with the eyes up and the cut side down in a hole or trench that is 4 inches deep. Provide 1 to 3 feet of space between plants. Cover the spuds with 2 inches of soil and then sprinkle with 2 tablespoons of low-nitrogen, high-phosphorous fertilizer; usually, these varieties are labeled as "flower food." Water the area well.

No matter where you have planted your potatoes, you'll want to create artificial hills to cover the taters as they grow. This means when the stem grows 6 inches tall, add potting soil or mulch around the base until all but 3 inches are covered. It's worth mentioning that potting soil will let you grow more potatoes, but mulch, particularly lightweight mulch like straw, makes harvesting much easier.

Hilling is a critical part of planting potatoes because it not only increases yields but also protects the potatoes from weeds, sunlight and cool weather. Keeping potatoes out of the sun is particularly important since photosynthesis causes potatoes to turn green, building up toxic solanine compounds that cause severe stomach upset when eaten.

Stop hilling when the potatoes are growing flowers. This is a sign that the potatoes are almost ready for harvest. Potatoes can take anywhere from around 70 to 100 days to reach maturity depending on the variety and growing conditions. You'll know you have mature potatoes that are ready to be harvested when the vines die off.

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In What Zone Do Potatoes Grow Best?

One of the many amazing things about growing potatoes is that they can be grown practically anywhere. That being said, you can't grow any variety of potatoes anywhere. While most commercial varieties can be grown in USDA hardiness zones 3 through 10b (which covers the overwhelming majority of the continental U.S.), there are some heirloom varieties that can be grown in tropical or arctic climates.

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If you live somewhere particularly frigid or tropical, you might ask local farmers in your area about the varieties with which they have had luck. Generally, those in arctic areas will want to plant their seed potatoes after the last frost has passed, and the soil temperature is routinely 50 degrees Fahrenheit. In these areas, it is best to seek out smaller potato varieties that reach maturity faster. Those hoping to grow potatoes in tropical climates will want to plant in early spring or late summer to avoid the peak humidity of midsummer that can cause potatoes to rot.

When Should You Plant Potatoes?

For gardeners in the continental U.S., potatoes can be planted as early as four weeks from your last frost date if you want to be able to harvest potatoes as soon as possible, but you will have a greater yield and minimize the chances of frost or water damage to the plants when you wait until after the last frost date. Ideally, the soil temperature should be at least 50 degrees, and the soil should not be so wet that it sticks together. To protect potato foliage before the last threat of frost, cover young plants with landscape cloth.

Generally, those in warmer areas can plant around Valentine's Day, while those in cooler regions should wait until around Easter. Those in warm regions with little risk of frost can even start a second crop in fall.

Soil, Sunlight and Water Recommendations for Potatoes

Potatoes like loose, slightly acidic soil that is high in nutrients. For best results, add compost or manure to enhance the soil. You may also consider adding peat moss to increase drainage and reduce clumping that can lead to rot. An ideal pH is around 5.0 to 6.5. If your soil pH is too high, add a little sulfur to the soil prior to planting, or you can even dust your potato pieces in sulfur.

While the tubers themselves need to grow in the dark in order to discourage the greening of the potatoes and development of toxic solanine compound, the foliage requires ample sunlight. Ideally, they should have at least six hours of full sun every day.

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Potatoes should have between 1 and 2 inches of water a week. It's particularly important to ensure this level is maintained throughout the plant's entire life cycle, or the potatoes can become misshapen since the individual tubers take so long to reach their full size.

How to Propagate Potatoes

The great thing about growing your own potatoes is that when you find a variety you like, you can grow more potatoes from your original crop. To go this route, it's important that you properly store your tubers so they won't sprout until the next potato growing season.

First, dig up your spuds and then brush off but don't wash away the dirt. Place them in a cool, dark place that will be consistently around 50 degrees. About a month before the growing season, put the seed potatoes somewhere they will be exposed to light, ideally in a high-humidity area. Once they've started sprouting, the potatoes are ready to be planted.

Do not attempt to grow plants from the seeds of the fruits as these are not nearly as reliable for growing new plants as seed potatoes and when they do sprout, it can take years to grow a new plant.

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How to Harvest Potatoes

When you are preparing to harvest your potatoes, you may be tempted to also collect the green fruits you see on the potato plant, but these, along with the leaves and stems are all filled with large amounts of the same toxic solanine compound that turns potatoes green when they are exposed to the sun. In fact, if you have children around, you should remove these fruit, otherwise, just leave the fruits to mature and fall off the plant, where they will further fertilize your plant until the foliage dies. (It's worth mentioning that the green fruits only grow in certain weather conditions and it's neither a good or bad sign if you have no fruit on your plants.)

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The foliage and stems will die away shortly after the fruits fall (or a little while after the flowers fall if your plants did not develop fruit) and then you'll know it's time to harvest your potatoes. Using your hands, a broadfork or a digging fork, dig around the edge of the potato growing area, working slowly and gently as you go. Start around the perimeter and then gently remove the soil from the hills. By working this way, you will minimize the chance that you will accidentally pierce the tubers while trying to uncover them. Use any potatoes injured during the harvest as soon as possible.

After you've revealed all of the spuds hidden in the soil, allow them to dry on top of the soil for an hour or two before brushing away the dirt and storing them in a paper bag. Do not wash potatoes until you are ready to eat them, as moisture can cause rot. Potatoes stored in a cool, dark, dry place can last for six months or longer, letting you enjoy potatoes all the way until your next growing season.

Common Pests and Other Problems for Potatoes

Colorado potato beetles are one of the biggest pests that affect potato crops. They eat large holes in leaves and may totally strip the shoots clean. You can identify them by their distinctive coloring; they have yellow backs with black stripes and orange heads.

To eliminate these pests, add food-grade diatomaceous earth to the soil to stop the nymphs and then hand pick the adult beetles. For particularly bad infestations, consider using pesticides safe for edible plants, such as Spinosad or Sevin. You can reduce the likelihood of infestation by planting potatoes near eggplant, flax or green beans. Many of these solutions will also stop other problematic beetles, such as flea beetles and blister beetles, but always wear gloves when handling blister beetles because they secrete an oil that can cause skin to blister.

Other potato pests include aphids, leafhoppers and spider mites. These pests can all be removed with insecticidal soap. If you notice that your potatoes have pitted, scab-like areas on them that need to be cut off, they are suffering from potato scab. This is usually caused by the soil not being acidic enough. Next time you plant potatoes, try dusting them in sulfur to reduce the pH of your soil as they grow. Also try growing varieties that are more resistant to potato scab.

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Common Diseases for Potatoes

The most common disease affecting potatoes is potato blight. This fungal disease can destroy an entire crop of plants, and there's no way to stop potato blight once it affects your crop. To help reduce the risk of infection, always buy seed potatoes that are certified disease-free, rotate crops every year and avoid planting potatoes, tomatoes, chili peppers, eggplants or other members of the nightshade family in the same soil for a three-year period whenever possible.

You might find that your sprouts fail to grow any larger or even die back after emerging. This can sometimes be a result of frost damage, but if the threat of frost has already passed or if you notice brown, sunken spots below the soil level, your plant might be suffering from blackleg or black scurf. In either of these cases, you'll want to remove and destroy any infected plants and their tubers.

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references

Jill Harness is a blogger with experience covering architecture, design and decor trends from around the globe. As she lives in what would politely be called a "fixer upper," she is particularly interested in writing about DIY projects and repairs. Most of her home design writing can be found at www.homesandhues.com. You can find out more about Jill's experience and learn how to contact her through her website, www.jillharness.com.