The Irish, famous for their historical love affair with the potato, say it best in this proverb, “Only two things in the world are too serious to be jested on, potatoes and matrimony.”
Matrimony aside, imagine a world without the potato! Solanum tuberosum, the botanical name of the potato, sits as one of the most beloved and important commercial crops globally. It is a vegetable that provides important nutrients and carbohydrates that are among the more digestible in tuberous roots. It is a vegetable historically that has contrasted famine and often starvation across the world and very few vegetables offer more versatility in the kitchen.
A member of the nightshade family or “Solanum” the potato is in good company as other members of this family include eggplants, tomatoes, and peppers. All of these plants contain alkaloid compounds in their leaves, stem, and green parts that are toxic. It is, in fact, the underground root of the potato plant that we consume known as an annual tuberous vegetable.
Potatoes contain carbohydrates, vitamin C (skin), potassium, vitamin B6, and trace amounts of zinc, iron, phosphorous, magnesium, niacin, folate, riboflavin, and thiamin. A potato with its skin has an equivalent amount of fiber as many whole grain cereals, pasta, or bread.
While the potato is relatively cheaper than other vegetables to procure, good homegrown potatoes boast a flavor that is hard to come by in commercial crops. While the more popular potato cultivars including red potatoes, new potatoes, or baking potatoes dominate the collective imaginary, the potato boasts more than 1000 varieties for cultivation. At your local garden nursery, you’ll probably find close to 100 varieties ready for cultivation. Shapes, textures, and flavor to some extent will vary from one cultivar to the next.
In more northern areas, seed potatoes can be planted as soon as the soil can be tilled once the final frost has passed. Soil bed temperatures should ideally be approximately 50°F. consistently. In warmer southern areas, potatoes may be cultivated as a winter crop being planted at some point between September to February. Consider that your potatoes will require from 90 to 120 days to mature for harvest.
When to Plant
Potatoes are a relatively easy crop to cultivate if a few basics are respected. Colder region gardeners should plan on planting between the middle and the end of spring, while those in warmer climates need to plant at the end of summer or toward the end of winter to avoid growth and development during the hottest months.
Selecting a Variety
Potatoes come in early and late varieties. You actually plant both types at the same time but the late variety will mature after the main potato crops have been harvested. When preparing for planting, it is recommended to purchase seed potatoes that are free of disease and certified. Growing grocery store potatoes will present a risk both for disease and because most are treated with a chemical growth inhibitor, to prevent eyes from forming and sprouting.
Choosing a Location
Keep in mind that potatoes need full sun. Avoid planting in the same spot as you have planted tomatoes, peppers, or eggplant the season before, as they share the same pests and problems as nightshade family members.
Potato Crop Necessities
Soil should ideally be loose, and well-draining. Potatoes need acidic soil that has a pH between 5.0 and 6.0. If your pH is higher, your crop will be susceptible to scabs which will form rough spots on the potato. These tubers don’t enjoy rich soil beds, so it’s enough to have some organic matter in the soil and a neutral to acidic pH level. If your soil is clay-based and heavy, amend it to the depth where the tubers will grow.
Potatoes need full sun exposure. They will manage with partial shade, but it is the rather lush vegetation above ground that feeds the tubers below the soil surface. Six to eight hours of full sun daily will be appreciated. If your tubers grow too near to the surface, they will need to be protected from the sun by hilling the soil up around them.
Water and Humidity
A steady supply of water is needed for potato success. Potato plants must receive at least one inch of water weekly. They are highly sensitive to drought, particularly during blooming. Mulch can help your soil bed retain moisture. Humidity is not a problem.
If your area has very hot summers, plant potatoes as a winter crop. To plant, soil temperatures should be consistently between 45° and 50° Fahrenheit. Potato crops do better in cooler summers and tubers develop best when the soil temperature rests between 60° and 70°F. If the soil bed temp gets to 80°F., your potatoes will interrupt growth. Mulching with a very thick layer of straw can keep soil temps cooler.
Feed your potatoes immediately after planting with organic fertilizer, preferably a slow-release product. Offer them organic liquid fertilizer diluted to half-strength every two weeks.
Preparing the Soil Bed and Planting
Planting seed potatoes is generally done using one of two methods: scattering or the trench and hill solution.
· Scatter Planting
This calls for gardeners to lay seed potatoes on the soil bed and then cover them with a couple of inches of mulch. You add on mulch layers as plants grow. If your area is home to rodents, this method is ill-advised.
· Trench and Hill Planting
This is a more traditional method that involves digging a trench that is approximately six inches in depth and positioning the seed potatoes in the trench with the eyes facing upward. You then cover the seed potatoes with several inches of soil. As the plant grows, you move soil around it, creating small hills around the plant. With this method, the soil remains loose but the tubers remain covered and protected from exposition to sunlight which will increase toxicity and turn them green. Hilling should continue until plants bloom.
Most potatoes will require two to four mont
hs or 120 days to reach their full size. When the tops of plants die off, you’ll know your crop is ready for harvest. If the soil bed is not wet, potatoes can be left in the soil for an extra couple of weeks. Harvest your potatoes by removing them by hand or with a trowel. Turn soil gently to find the tubers. As tubers will branch, avoid using a fork to prevent damaging your crop. You can eat damaged potatoes, but they do not keep.
Smaller new potatoes can be harvested once the plant reaches a foot in height. When your potato plant is blooming, new potatoes are generally ready for harvesting. Remove them gently to avoid damaging plants or tubers.
Potato Problems, Diseases, and Pests
Potatoes, as history has shown, are susceptible to pests and diseases. Pests to be on the lookout for include:
- Beetles – check the underside of foliage for eggs and larvae and remove manually.
- Wireworms – these worms attack the tuber underground, so crop rotation is one of the most effective methods for contrasting them.
Common diseases include:
- Late Blight – this is the disease that caused the Irish famine with mass starvation, over a million deaths, and more than 2 million emigrating. Leaves turn black and then become moldy. Plants affected by potato blight need to be removed and burned. They should not be composted. Tubers can be harvested after a few weeks. Disease-resistant varieties that are certified will avoid this risk.
- Scab – this disease has the appearance of corky patches or sunken holes on the tuber’s surface. Soil can be amended with peat moss and lowering the pH of the soil will aid in controlling scabs.
Seed potatoes used in planting are not seeds but mature potatoes cultivated specifically for planting. They sprout green shoots from potato eyes. These potatoes can be planted whole or cut into pieces for cultivation, but each piece should contain one to three eyes. If you cut, allow the pieces to callus overnight before planting. You can also dust pieces with a powder fungicide to prevent rotting.
A Final Thought
“The man who has nothing to boast of but his ancestors is like a potato – the only good belonging to him is under ground.”– Sir Thomas Overbury (1581-1613)