How To Grow Potatoes
- 1. Structure and Function of the Potato Plant
- 2. Soil Preparation
- 3. Planting and Maintaining the Potato Plants
- 4. Harvesting and Storing Potatoes
- 5. Final Word
People first learned how to grow potatoes in the Andes thousands of years ago.
But the plant did not make its way out of South America until the sixteenth century, when European explorers brought it (along with so many other New World plants) back to the royal courts of Spain and Portugal, where Europeans learned how to grow potatoes.
However the plant’s stubborn adaptability, as well as its storage value and versatility in the kitchen soon helped it to spread around the world.
Now potatoes are a staple of cuisines from South Asia, to Europe, North America and the Middle East.
Potatoes can be baked, boiled, mashed, fried, or ground into flour. They can be stored in the pantry for months. The careful gardener will find it is not very difficult to learn how to grow potatoes.
This guide will teach you exactly how to grow potatoes. When you are learning how to grow potatoes, the first thing you will find is that they are unlike most vegetables grown in the garden in two important respects. The first is that they grow underground, and therefore require you to continually be building up a hill of soil over and around the plant to protect the tubers from sunlight. The second and more unique aspect of how to grow potatoes is that they must be grown from seed pieces in order to produce true cultivars. Seed pieces are usually available at garden centers and nurseries, and they will keep for months or even years.
In this guide on how to grow potatoes, I will begin by discussing the structure and function of the plant, which is important to understand when you are learning how to grow potatoes. Then I will discuss proper soil preparation for how to grow potatoes. This section, which will be the longest one in this guide, is critically important to understand in order to know how to grow potatoes that have high yields, are resistant to disease, and have great flavor and large size. Then I will talk about planting and maintaining your potatoes, as well as how you can protect them from disease and pests. Finally I will cover how and when to harvest potatoes and how to store your potatoes so you can fully enjoy your yield.
I hope this guide is fun and informative, and that by the end of it you feel fully versed in how to grow potatoes. Enjoy!
1. Structure and Function of the Potato Plant
In order to learn how to grow potatoes, it is important to understand the structure of the potato plant and the function of each of its parts. Potato plants do not grow in the same way that other plants do, that is, from a seed. A potato plant is made of one or more stems that have grown from a seed tuber or seed piece. The seed tuber was once a potato itself. The tubers themselves are underground stems that grow from stolons, or rhizomes, not roots.
After providing the energy the plant needs to emerge, the seed piece will typically disintegrate. Since seed pieces usually have more than one eye, a potato plant can have several main stems, all of which grow out of an eye on the main tuber. In addition, a potato plant usually has several lateral stems that grow from buds on the above-ground stems. A temperature between 65 and 80 degrees Fahrenheit is generally considered to be best for healthy vine growth. All of this is important to understand in order to learn how to grow potatoes correctly.
You also need to learn how to grow potatoes of each of their two rather different categories. Determinate types, which stop producing new growth after tubers have started, tend to be fairly short, with fewer flower clusters and mature earlier than indeterminate types. Indeterminate types, which continue producing new growth until they die or are killed, require a longer growing season and therefore can potentially produce a larger yield than determinate ones. When you first learn how to grow potatoes, it is usually best to start with indeterminate types.
Potato leaves are large, compound leaves that grow out of the stalk in a spiral pattern, and are functional for about forty days after they first appear. Because of this, it is important to trim older leaves to allow them to be replaced by newer ones. Very hot spells, drought, or lack of nutrients can all result in the leaves aging more quickly. In determinate potato plants, the leaves along with the plant as a whole are generally not able to recover from exposure to severe stress, and can die as a result.
Potato flowers have both the female pistil and the male stamen in them. The color of the flowers can be white, red, blue, or purple, and can even have different color patterns on them. Potatoes are pollinated by insects, especially bumblebees, and so a useful way of how to grow potatoes is in a garden that has plenty of other flowers that will attract pollinators, such as bee’s balm, salvia, and other similar plants.
Some potato varieties will have flowers that produce fruit when they are mature. These fruit can be harvested for their seeds, which can be stored in a cool, dry place for up to ten years. The seeds can be used to grow new potato plants, but these plants will not be true offspring of the parent plants, and may produce different flowers and tubers than the plant the seeds came from. When you learn how to grow potatoes from seeds, instead of seed pieces of tubers, be prepared for plants that are different than their parents.
1c. The Underground Plant Structure
Potato rhizomes, or stolons, are underground stems that grow horizontally along the subsurface of the soil. Tubers are formed by the swelling of the end of the rhizomes. Not all rhizomes will become tubers. Tips of rhizomes that are not covered by the soil will grow into vertical stems, and grow leaves. The growth of tubers is basically governed by the length of the day and temperature of the soil. When you are beginning to learn how to grow potatoes, it is important that you begin them while the day length is still relatively short.
A fairly cool temperature at night (between 50 and 60 degrees Fahrenheit) is best for the promotion of tuber growth and therefore also best for how to grow potatoes. While the tubers are growing, it is also very important to make sure there are adequate levels of moisture in the soil. If the plants do not receive enough water during the early stages of tuber growth, you can lose potatoes as they will be reabsorbed by the rhizome.
Depending on the potato variety, the shape of the tuber can vary from very long, thin fingerling types to almost perfectly round potatoes. All tubers, even round ones, have two ends. The heel, or stem end, is where the tuber was attached to the rhizome before it was picked. The seed end (also called the rose end or apical end) is at the far side, furthest away from where it was attached to the rhizome.
The eyes of the potato are located around the middle of the potato. Each eye contains several buds, and it is through the eyes that the potato tuber “breathes.” If the soil is kept very wet for a prolonged period, and becomes waterlogged, there is much less oxygen available to the plant. During these times the potato’s eyes can open and enlarge to the point where they become very prominent.
Just like the leaves on aboveground stems, the eyes on a potato are arranged in a spiral fashion. They tend to be mostly concentrated towards the seed end of the tuber. They are fewer in number and farther apart toward the stem end of the tuber. The lower part of the sprout produces stolons and roots while the upper part is what grows into a stem.
Immediately after they are harvested, potato tubers enter a resting period and are referred to as dormant. The buds, which will grow from the eyes of the potato, are actually dormant while the potatoes are still growing. The length of the dormancy period after they have been harvested will vary depending on a number of factors, the most important of which is the storage temperature. The growing conditions during the previous season can also have an effect on dormancy period, but that is not something you can have any real control over while you are growing potatoes.
The best temperature for storing seed potatoes is about 40 degrees Fahrenheit. Storing them at higher temperatures will shorten the dormancy period, which will result in potatoes ageing more quickly. As they age, potatoes will grow new stems from their eyes, and will eventually become water stressed, when they will shrivel and die. For this reason it is best to store potatoes at around the optimal forty degree temperature, and cook them as soon as they begin to grow new stems.
2. Soil Preparation
You may ask yourself “is soil preparation an important aspect of how to grow potatoes?” The answer is yes. The type of soil, how it is prepared, and the levels of nutrients available to the plant will have a major effect on the size of the yield and the quality of the potatoes produced. For this reason, it is important when you are learning how to grow potatoes to pay close attention to the soil preparation. Potatoes are adapted to many soil types but the right adjustments in preparation and fertility are often required to get the most from the soil. Knowing the physical character and the natural fertility of the soil is a good starting point for a successful approach to how to grow potatoes.
Soils are reservoirs of nutrients, water, and oxygen. All of these things are necessary for plant growth. The right combination of physical and chemical properties is absolutely critical to growing a good crop of healthy, tasty potatoes. That said, potatoes can be and are grown in many different soil types. They are grown commercially on a very wide range of mineral soils, all the way from sandy soils in Florida to clay rich soils in North Dakota and Minnesota. They can also be grown in organically rich peat soils. Regardless of the soil type, the main concern in how to grow potatoes is to make the right adjustments to the soil to provide a well drained environment for the plant’s root system. Sandy or loamy soils are ideal for how to grow potato plants.
2a. Water Holding Capacity of Soils
The capacity for holding water is very important for how to grow potatoes in areas where water is precious and in limited supply, such as the American Southwest, California, and the like. Understanding how to grow potatoes in water poor areas is a major aspect of producing a good crop in that region. However, in areas where watering is not as much of a concern, this is less important. Still, in areas where irrigation is readily available, you have to be careful to avoid water-logging the soil. Waterlogged soils starve roots of the oxygen they need to grow and create an environment that is rich for bacterial growth. Bacteria can enter potato tubers under these conditions and lead to rot or blight. In areas where internal drainage is poor, it is important to build raised beds to provide for surface drainage. There is less potential for water-logging in sandy soils, but on the other hand, there is a greater need to maintain adequate moisture.
2b. Nutrient and Mineral Content of Soils
Organic matter in mineral soils improves soil structure and helps to provide moisture and nutrients to the plant. Rotating grasses and legumes through a bed that you use to grow potatoes will also help improve soil structure. Often, backyard gardeners will not have the luxury of rotating sod crops into their beds, so another option is to plant rye or other cold season cover crops at the end of the growing season. The organic matter and the root growth of these plants will improve the nutrient content and keep the soil from becoming compacted.
Additions of manure or compost will benefit all soil types. In soils that are rich with clay, organic matter improves the soil structure and therefore provides better aeration and water drainage, both of which are very important for root and tuber growth. In sandy soils the organic matter binds the soil particles together and increases the capacity of the soil to retain water, along with improving nutrient availability. Ideally the addition of manure or compost should be made a year or more before the beds are used for growing potatoes. Adding manure in the same year potatoes are growing can increase scabbing of the potato skins as well as raise the likelihood that bacteria could contaminate the potatoes. Therefore, you should add manure the year before you begin learning how to grow potatoes.
2c. Soil pH
Soil pH, which is a measure of the soil’s acidity or alkalinity, is important to managing scabbiness on potatoes and to the plant’s ability to take in nutrients. A pH level of 7.0 is considered neutral. In areas where soils are very acidic, keeping pH levels below 5.2 will help prevent potato scab. Growing potatoes at this pH level can present problems with nutrient availability as well as with rotating other plants into the bed.
In addition to the effect it has on scab, pH is an important factor in plant nutrition. Potatoes can be grown across a wide range of soil pH levels, with some adjustments. From a nutritional standpoint, a soil that has a slightly acidic pH is preferable. At pH levels near 6.0, soil nitrogen, phosphorus, potassium, calcium, magnesium, and other important elements are all readily available. When pH levels are at or below 5.5, nutrients are less available, and some, like iron, can even be toxic to the plant. At pH levels of 7.0 and higher, phosphorus and other nutrients will not be available to the plant. When pH levels are either too acidic or too basic, it may be necessary to apply nutrients to make it optimal for how to grow potatoes.
Potatoes remove a lot of nitrogen and potassium from the soil, as well as a smaller amount or phosphorus. Small amounts of other elements are also taken out of the soil. In most cases, a fertilizer that provides nitrogen, phosphorus, and potassium is good to apply to the bed you are growing potatoes in. In soils that have low pH levels, applying limestone will help with nutrient availability. It is also good to apply lime to beds the year before potatoes are grown in them in order to reduce scab.
Knowing the pH of the soil is the first step in successfully fertilizing the soil to grow potatoes. Kits for measuring your soil pH are available at garden supply stores, and can be purchased online as well. You can also send a sample of your soil to a local laboratory, which will test it for you and provide a full report not only of the soil pH but also of the nutrient makeup of the soil. When soil nutrient levels are too low, you should apply fertilizer, either in inorganic fertilizer or as organic compost or manure. Well-decomposed manure can be applied at a rate of fifty pounds per hundred square feet. At this amount, you will have a good base amount of nutrients. The manure should be applied either by using a rototiller to work it into the soil, or by double digging the bed.
2d. Preparing the Soil for Potatoes
Double digging is a method of loosening the soil in your garden while adding nutrient-rich compost to it below the surface. It is recommended to double dig every bed at least every other year, not only for the sake of adding nutrients, but because beds tend to settle and become compacted otherwise. Double digging is especially beneficial for how to grow potatoes.
First, using a spade, dig a trench about a foot (30 cm) deep, as wide again, and as long as the bed. Then, using a gardening fork, break up the bottom of the trench, also to a depth of about a foot (30 cm). While you are doing this, add compost to this layer. Then dig a second trench parallel to the first, using the soil removed from the second trench to fill in the first. Repeat as necessary until the entire bed has been double dug, using the soil left over from the first trench to fill in the last one. Take care not to walk on the bed, as this will compact the soil again.
Finished or partially decomposed compost can be used as mulch or used as a top dressing for how to grow potatoes. Break up the upper layers of the soil and till some of the compost to about four inches of depth. Then spread a layer of compost around the plants, and water them generously. Compost can be applied any time you think your potatoes need to be fertilized. A thick layer of three or four inches will conserve soil moisture and provide additional nutrients.
The amount of nitrogen that manure or compost will provide to your potatoes will vary by the kind of manure you use. Hot manures are nitrogen rich; examples of hot manure are rabbit or chicken manure. Cow and horse manure is less rich in nitrogen, but still provides some. Coffee grounds are also rich in nitrogen and can be added to your soil to raise its nitrogen levels. Applying wood ash can raise the pH of the soil as well as provide potassium, and bone meal will provide phosphorus. All of these are organic fertilizers, and will help build the soil structure as well as help to provide nutrients at a reasonable pace to the plant over the entire period of the growing season.
Typically you should prepare the soil close to the time of planting. Soil should be double dug or tilled until loose but not pulverized. Unlike true seed of many plants, seed potatoes do not need a fine seed bed. Overworking the soil breaks down the structure and can create a sealing effect that will reduce the needed air exchange to seed roots and to developing potatoes later in the growing season. The soil should be turned or double dug when it is dry enough to work. Tilling soil while it is wet will compact it and wind up creating poor physical conditions that will last through the entire growing season. When the soil is compacted, air circulation, drainage, and water penetration will all be negatively impacted.
Soils that are rich in clay are the most difficult to properly get ready for how to plant potatoes. There is a very fine line between clay soil that has ideal soil moisture and one that is too wet. Development of good soil structure with the addition of organic matter and rotating with seed crops, as discussed above, can improve the growth of crops in soils rich with clay. In northern areas of America, where the summers can get particularly humid, heavy clay soils can need to be worked in the fall. Doing this allows the freezing and thawing of the soil during winter to break it apart and results in better aerated soil. In arid areas it may be necessary to water the soil thoroughly before it is worked. Care should be taken to make sure you do not work soil in arid areas when it is excessively wet.
3. Planting and Maintaining the Potato Plants
The date you choose to plant when you are learning how to grow potatoes will vary based on where you are located and also when you want to harvest them. In the northern latitudes of the United States and Canada, potatoes should be planted between late April and early June. In the mid-Atlantic area, potatoes should be planted in early spring, between March and April. In the American South and Southwest, potatoes should be planted between November and February.
3a. Planting and Tilling
Planting generally begins about two weeks before the last frost date. Young sprouts can put up with temperatures as low as 28 degrees Fahrenheit. At the time of planting the soil temperature should be between 45 and 70 degrees Fahrenheit. Generally speaking, planting potatoes early will result in large yields of high quality tubers.
You may need to adjust the date of planting in order to make the most of your local environmental conditions. For example, planting potatoes late in areas where temperatures are high late in the summer and through the early fall can result in tubers that decay while they are in the ground. As a general rule, planting potatoes earlier in the growing season is better.
Tilling the soil after you plant potatoes is very important in order to keep weeds down, as well as break up soil to improve air circulation. It is also important to till the soil in order to build up hills to prevent the tubers from becoming green, The best time to control weeds is early in the season when they are just beginning to sprout. Tilling does not need to be deep in order to work well. Usually, just breaking up the soil surface with a hoe or sturdy rake, to a depth of one to two inches, is all you need to do.
Shaping the soil into broad hills around and over the potato plant allows room for the potatoes to grow and prevents them from being exposed to sunlight. Building up the hills should be a gradual, continuous process that you begin to do when the plants are six to eight inches tall. If the potato tubers are exposed to direct sunlight, they will turn green and bitter. In order to be effective, the hills should completely cover all of the developing tubers. The best kind of hill will be wide, rather than tall and pointed, with an even surface. Hilling should be completely finished by the time the potato plants’ flowers are blooming. This will be about thirty to forty days after the plants first emerge from the soil. Cultivating and tilling the soil should never be done while it is wet.
Proper soil moisture is important through the whole season to maintain good production and quality of the potato crop. In more humid regions, it is very important to have good surface and internal soil drainage. Too much water around seed pieces early in the growing season will increase the potential for them to decay, which can result in losing an entire crop. Wet, cool conditions early in the season can also increase certain bacterial diseases, which will reduce or delay growth entirely, and in some cases result in plants not forming above ground.
Too much water during the growing season and at harvest can also starve the roots and tubers of oxygen, which will result in large eyes or even tuber decay. Too much water on the leaves of the plant for long periods of time can result in late potato blight. This is the disease that was responsible for the Irish potato famine of the nineteenth century. On the other hand, not enough moisture can result in low yields of small tubers. Consistent levels of moisture is important, since fluctuating moisture levels between wet and dry conditions will result in poorly formed potatoes that may be knobby or cracked.
Deciding on the optimal water amount for how to grow potatoes that are healthy depends on which stage of growth they are in at a given time, as well as the kind of soil you have and its ability to hold water or drain properly, and of course weather conditions. Just after planting the seed pieces, when the root system is still fairly sparse, the plants do not need a lot of water. The need for water will increase as the plants continue to develop, and demand will level off about two weeks after the leaves and stalk of the plant are fully grown and developed. Unless the soil is particularly dry it is rather unlikely that you will need to water more often than normal rainfall for at least the first month to six weeks of planting. The point of watering should be to keep the soil evenly moist but not overly wet. Potatoes are very thirsty plants, but their root systems are fairly shallow. While roots can extend as much as two feet from the main plant, moist of the uptake of water occurs in the first twelve to fourteen inches of the root.
More sandy soil has fine particles that cut back on the ability of the roots to take up water. Therefore, overwatering soils that are sandy, as well as overwatering well drained soils, can result in washing or leaching away the soil’s nutrients. And because these soils do not hold water well, applying a lot of water all at one time will not help you to extend the amount of time between irrigations. If possible, it is best to avoid sandy soils altogether when you are beginning to learn how to grow potatoes.
There are a number of different ways you can apply water, but the most common by far is using an overhead sprinkler. You should take care to apply the water uniformly. Furrow irrigation and underground watering systems are rather specialized methods, but they can be used if you are growing a lot of crops.
By far one of the best watering methods for potatoes in particular and all vegetables generally is the drip tape or drip hose method. This is also a great way to conserve your water use, and convenient in all types of garden beds. Because the water is applied at the soil surface with this method, there is very little danger of leaf-borne diseases such as blight. Drip irrigation is best to do along with a healthy layer of mulch or compost on the soil surface, which will help retain water and prevent the soil from drying out.
3c. How To Grow Potatoes Without Pests and Disease
There are quite a few pests and diseases that can attack your potatoes; so many, in fact, that an entire guide could be written about that subject alone. At the very least, you can take preventative steps to keep disease and pests away from your potatoes. Disease prevention is best done by planting your potatoes as early as possible, so they are not exposed to hot temperatures late in the growing season, and being sure you do not over-water them. Keep a keen eye on the potato plants’ leaves, as well: they are the best way to find out whether your potatoes are healthy or suffering from disease. Discoloration and spots indicate that the plant is under attack. Plants that have become infected should be removed and destroyed immediately to prevent disease from spreading to the entire crop. If plants do show signs of disease, take note of the coloration and consult a gardening professional. Also, reassess the soil conditions when disease is present to determine if they are sub-optimal for potatoes.
Infestations of harmful insects are the bane of any gardener’s existence; potato growers are no exception to this. There is nothing quite so disappointing to come to the garden one morning and find holes chewed into the leaves or stems of potatoes that you have been painstakingly cultivating from seed pieces, especially if you have just started to learn how to grow potatoes. While there are several different methods to controlling insects in your garden, a number of them have drawbacks. Chemical insecticides not only introduce toxins to the garden, they may be passed on to you or anyone else who eats the potatoes you grow. Chemical insecticides are also not sustainable in the sense that they do not help to create an ecological balance in the garden. A truly healthy vegetable garden bed grows best when it reflects the natural world’s checks and balances. Insecticides, whether organic or inorganic, also do not discriminate between harmful insects and beneficial ones – the insects which will patrol your potato patch and devour unwanted intruders.
There are a number of fragrant, attractive, and edible plants and herbs that you can grow in your garden which will act as a deterrent for the vast majority of insect pests. They will not keep harmful insects out of your garden altogether, but if they are planted in tandem with the potato plants and the other vegetables you want to protect, they will go a long way to keeping pests away from your prize plants.
The technique of planting deterrent plants among those you wish to protect is part of a strategy called companion planting. Companion planting is quite simply the practice of growing plants that benefit from one another’s company next to one another. Certain techniques involve planting vegetables that take nitrogen from the soil with those that return it to the soil; planting tall plants like sunflowers with climbing vegetables like beans, to act as natural trellises; and, as discussed here, planting fragrant herbs and flowers among vegetables and ornamentals to protect them from pests.
Nasturtiums, coriander, catnip, and tansy will all repel the insects that prey on potato plants, in particular the Colorado potato beetle. In addition, companion planting potatoes with beans, cabbage, corn, or horseradish will not only support the soil structure and provide nutrients for the growing potatoes, but also improve the flavor of the potatoes when they are harvested.
4. Harvesting and Storing Potatoes
You can harvest potatoes when they are young, early in the growing season, but they will not store or keep well, and so you will have to eat them very soon after you harvest them. Harvesting potatoes early in the growing season will also reduce you overall yield. Waiting to harvest potatoes until later in the growing season will increase your yield and provide you with potatoes that can last several years if they are properly stored. I recommend waiting when you are first learning how to grow potatoes so that you get the most out of your efforts.
Unless the potato plants are over-fertilized, the leaves of the plants will begin to turn yellow and dry out towards the end of the growing season. This process will usually start at the lower leaves and move up the plant. Leaves and stems of early and mid season plants are usually dry already by the end of the growing season.
In order to make sure that you get the best possible skin on the potatoes, and therefore lower the likelihood of bruising and shriveling after harvest, potatoes should be harvested no sooner than two weeks after the aboveground plants have died, dried, and yellowed. Plants that are still green and growing about two or three weeks before the first frost date should have their leaves removed in order to allow the process of the skin setting to begin.
The best way to harvest potatoes in a backyard garden is generally to use a spading fork or potato hook, but if you do not have one you can simply use a spade or trowel to do the job. Harvesting potatoes by hand requires you to have a good idea of where the tubers are located in the potato hill in order to avoid damaging them. This can be difficult to ascertain, especially when you are first learning how to grow potatoes. The first time you harvest potatoes, I recommend you use a hand trowel, and gently explore potato hill, loosening soil slowly to find potatoes.
Storing potatoes extends the amount of time you can enjoy the growing experience. Depending on the physical characteristics of the area you are using to store the potatoes, and also the condition of the potatoes when they are being put into storage, they can usually be stored between six months and a year. Successful storage begins with fully mature potatoes that are in good physical condition. Then, make sure the potatoes are being stored in a cool dry place where temperatures will be between 35 and 45 degrees Fahrenheit. The perfect storage temperature will be precisely at forty degrees.
5. Final Word
I hope this guide on how to grow potatoes has been informative and fun. In it, we learned about the different parts of the potato plant; what soil types are best for how to grow potatoes, how to plant potatoes and care for them; how to naturally keep pests away from your potatoes; and how to harvest and store potatoes.
Learning how to grow potatoes can be a wonderful experience. Once you have learned how to grow potatoes, harvesting and storing your crop, as well as sharing it with friends and family, can be a very rewarding experience. Now that you know how to grow potatoes, it’s time to start browsing seed catalogs and deciding which varieties you want to grow first!