Potatoes are one of the easiest crops to grow in your garden if you follow these simple tips.
By Guest Author Dr. Leonard Perry.
Potatoes are easy to grow by several methods and by following a few key tips. You can have varieties you won’t find elsewhere and potatoes with better flavor when you grow your own.
Potato growers in large commercial fields often face several problems they control with chemicals. This gives store-bought potatoes a listing on the Environmental Working Group’s “dirty dozen”—those vegetables reported to contain the most pesticide residues. Of course, you can avoid such concerns if you buy from local organic farmers, but even they may use organic chemicals you wouldn’t need in a home garden.
Types of potatoes for your garden
There are so many varieties of potatoes for your garden that you won’t find in stores or from local growers. Potatoes can be grouped by use, size, or color and vary in texture and flavor.
- Russet potatoes are the types you see in stores. They have brown skin and a large elongated shape, and they are mostly used for baking.
- “New” potatoes are harvested small and immature and aren’t necessarily red, as often believed.
- Red potatoes (on the outside) can be red, white, or yellow on the inside.
- White potatoes (on the outside) can be white or yellow inside.
- Purple potatoes, both outside and inside, may turn blue when cooking.
- Fingerlings are shaped like fingers or stubby carrots.
How to grow potatoes
Technically, potatoes are tubers, which are storage organs. Like tomatoes, potatoes can be grown from true seeds, which you would sow indoors about eight weeks before your last frost date.
More often, they’re started from “seed potatoes,” which aren’t actual seeds but chunks of potato with sprouts, buds, or “eyes.” You’ll find these in garden catalogs and stores in the spring. Look for certified disease-free seed potatoes. Don’t use store-bought potatoes, as these usually have been treated with an inhibitor to prevent sprouting and might carry diseases.
How to prepare and plant “seed” potatoes
Golf-ball-sized seed potatoes can be planted directly in your garden. Larger tubers should be cut into pieces about two inches thick or weighing about 2 ounces, and each piece should contain a couple of the new shoots or “eyes.” The shoots should still be short, just sprouting, and not have stems on them yet. If they have started growing, handle them gently to avoid breaking these tender stems. If you’re cutting a large tuber into sections, allow the pieces to harden off in a cool (55 to 65 degrees F), well-ventilated area for a day or two before planting.
When to plant potatoes
Plant seed potatoes outside 2-3 weeks before your last frost date, around the time daffodils bloom and soil temperatures are at least 50 degrees (F). While frost won’t hurt the potatoes in the ground, it can damage new shoots above ground. So, if a frost is expected after you see above-ground growth, cover the new potato shoots with a frost cloth, a converted plastic milk jug, or similar protection. Learn how to determine your last frost date.
“Hill” the soil so growing potatoes are not exposed to light
The principle to keep in mind when growing potatoes is that you want the new potato tubers that form to be underground, completely out of the light, so they don’t turn green (this makes them bitter and slightly toxic).
There are two methods of planting potatoes to keep them in the dark:
- Plant seed potatoes about 3 inches deep in trenches, about a foot apart, with rows 3 feet apart. Then, as the plants grow, mound or “hill” up the soil (or compost or straw) around them, covering about one-half to two-thirds of the plant. If using straw, first cover the soil with a couple inches of compost before adding subsequent straw layers.
- A variation on straw hilling begins by digging a foot-deep trench. The seed potatoes are planted in the bottom of the trench, but three inches deeper. As the plants grow, first add a few inches of compost, then just straw, eventually filling in the trench.
No garden? You can plant potatoes in containers or bags.
If you’re short on space or sunlight, consider planting potatoes in containers. This is the method I use,, with potatoes growing in thick felt-like bags made just for growing such crops. Although the bags hold about 15 gallons of mix, I only use about 12 gallons. I start with about 6 to 8 inches of compost and potting soil mix, then as the plants grow, I add more until the bag is about 3/4 full. A square wooden frame or wire mesh cage could be used similarly.
Potato growing tips:
- Although some recommend a low pH or acidic soil to avoid scab disease, potatoes often grow well over a range of soil pH from 5.0 to 6.5, with 5.5 to 6.0 perhaps ideal.
- Soils should be well-drained and not soggy.
- Potatoes need some nitrogen, but not too much, or you’ll have lots of leaves and shoots and small tubers. In fertile soil, compost may be all that is needed. Avoid manures, as these can lead to scab disease. Otherwise, add a garden fertilizer according to soil test recommendations.
- The main key to good yields is keeping plants well-watered, especially after bloom until shortly before harvest, while new tubers are forming. Mulches help too.
Potato diseases and pests
Scab
One of the most common diseases of potatoes is “scab,” caused by bacteria. “Scab” gets its name from the appearance of corky dark lesions on the potato’s surface. Potatoes with “scab” are still edible but must be peeled. As already noted, avoiding manures and alkaline soils helps to prevent this organism from growing, as does proper watering. Also, avoid planting potatoes in the same spot for three years (use proper crop rotation) or where other root crops such as carrots, beets, and turnips have been planted. Some varieties that are resistant to scab include Russet Burbank, Norgold, Red Norland, and Superior.
Late Blight
A common fungal disease of potatoes that may also spread to related crops is late blight. This is the famous disease of the Irish potato famine of the 1840s. Crop rotation helps avoid late blight as well as other diseases. It’s also advisable to not plant potatoes in the same area as tomatoes, peppers, eggplants, and strawberries for three years. Don’t leave any tubers in the ground or save them from previous years if late blight has been present. Also, use certified disease-free seed potatoes. Organic sprays are available to treat this disease.
Colorado Potato Beetle
The main insect pest of potatoes is the pretty, somewhat rounded Colorado potato beetle. They can quickly decimate your potato crop. Watch for it soon after the first leaves emerge and handpick them off. Look under leaves for clusters of bright orange eggs and destroy these as well. The eggs hatch the larvae that feed on the leaves. Covering plants with floating row covers goes a long way to keeping the Colorado Potato Beetle away, as well as other insects such as leafhoppers, flea beetles, and aphids.
Unfortunately, Colorado Potato Beetles have grown resistant to many chemical pesticides. Colorado potato beetles can be controlled with the organic pesticides diatomaceous earth, azadirachtin, or spinosad.
- Azadirachtin (Neem) – is derived from the Neem tree of Asia and Africa. It is effective for a few days, and repeat applications are usually necessary.
- Spinosad is made from the soil bacterium Saccharopolyspora spinosa. It is effective for about 10-14 days.
If you have a small garden, it may be most effective to simply pick the beetles off your potato foliage. Drop them into a bottle of water with dish soap to quickly smother them.
How to harvest and store potatoes
You can harvest “new” potatoes about two months after planting, but they will not store well, so use them immediately. Mature potatoes are ready for harvest and storage when their foliage tops yellow and mostly die back—about 4 months after planting or after they’re killed by fall frosts.
To dig potatoes out of the soil, you must be very careful, as they’re easily damaged by equipment and easily lost in the soil. The best method is to gently lift them from your soil with a garden fork. Brush the soil off the tubers, but don’t wash them until ready to eat. Allow them to “cure” at high humidity (75 to 90 percent) in a cool room (40 to 50 degrees). Curing helps the skins to thicken and heals any minor damage before storage.
Mine, stored in very slightly moist compost last well for 6 months or more. Some varieties stored just above freezing may become sweeter. Leaving them out at room temperature for a few days may help if they are too sweet. Before cooking, cut off any green or damaged areas.
This article originally appeared on Perrys Perennials.
I planted seed potatoes very deep in a raised veggie garden, then top dressed the garden thinking nothing was happening with the seeds, since they have shot out and are looking great, however have limited space to cover the leafs , I have used straw.. Do I need to cover the leafs, as the seeds are planted so deep?… never grown spuds before!!, thanks any advise would be grateful?
Hanna: Nope, don’t cover the leaves. Just protect the soil with straw and they’ll grow just fine.
Very good article on growing potatoes. I have a smaller backyard garden with limited space, I use half garbage cans to grow my potatoes. I can provide more info if anyone is interested.