Where to plant
Potatoes require full sun and a light, well-drained, slightly acid soil with a pH range
between 4.8 and 6.0. Avoid
excessively wet soils. Work in plenty of organic matter to lighten and improve the drainage in heavy clay soils.
To prevent transmitting soil borne diseases, do not plant potatoes where potatoes, tomatoes, strawberries or eggplants have grown in the previous year. Also, do not plant potatoes in freshly turned grass sod to avoid wireworms.
When to plant
Potatoes are cool weather plants. Potato“eyes”, from which the sprouts will grow, may be set out 2 weeks prior to the last expected spring frost, when the ground is dry enough to work. In the North, this is usually sometime in March. In the South, potato eyes may be started from January on and again in late August for a fall crop.
How to Plant
The conventional method of planting potatoes is to lay the mini-tuber in a trench and hill up soil around the plants throughout the growing period. If the tubers are big, it’s okay to cut them into sections. Just make sure each section has at least 2 eyes. Open a furrow, 4–5" deep and 6–8" wide, and work a light dressing of all-purpose 5–10–5 fertilizer into the soil at the bottom of the trench.
Plant the mini-tubers 2–3' apart and cover with 3–4" of soil. Firm the soil over the potato sections to encourage deep rooting. Space trenches 3' apart.
If there is danger of frost, cover rows with straw or newspaper until the shoots are 3–4"
tall or until frost danger is over. When plants are about 5" high, hill up soil from the sides
of the trench around each plant almost covering the foliage. Continue the process as plants
grow, usually about every 2 weeks. The hills keep the plants cool and
prevent the potatoes from forming near the surface where light will cause the tubers to turn green and become poisonous. Hilling suppresses weeds and keeps roots deep in the soil where more moisture is available.
Control weeds around the plants and between rows, but be careful not to bruise or cut the young tubers which are forming just under the soil surface. Such wounds may result in bacterial soft rot infection.
Potatoes require plenty of water and it is important to keep the plants evenly and consistently moist throughout the growing season. Uneven growth caused by periods of drought when the tubers are forming (around flowering time) will decrease production and result in knobby, cracked or hollow-hearted tubers.
In areas with very sandy soil, additional side dressings of 5–10–5 fertilizer may be needed when the plants are about 12" high and the first blossoms appear.
Colorado Potato Beetle The beetles are identified by a yellow and black striped back and are the most serious pest for potatoes. Larvae are red; bright orange eggs are found on undersides of leaves. Potato beetles can be hand picked and destroyed at any stage of growth.
Flea Beetle A small dark brownish-black beetle which chews small holes in foliage.
Leafhoppers and Aphids Both are tiny green insects. Aphids are found clustered on the underside of leaves and tips of shoots; leafhoppers congregate along stems and on tops of leaves.
Early Potato Blight Infected leaves show dark brown, circular lesions with a concentric, bull’s eye pattern.
Verticillium Wilt This soil-borne fungus initially causes yellow v-shaped lesions on the lower leaves.
Potato Scab Causes brown pustules or pits to develop on the tuber skin and extend into the tuber.
NOTE: When using chemical controls always follow manufacturer’s application recommendations.
Harvest potatoes about 15 weeks from planting. “New Potatoes”—may be harvested as soon as the plants begin to flower.
When digging “New Potatoes”, work carefully and disturb the plants as little as possible. With your hands or a trowel, gently lift the top layer of soil or mulch around the plants, pick as many potatoes as needed, then replace and firm the soil or mulch. Take only a few of these immature potatoes from each plant. The remaining potatoes will continue to grow and provide your main crop. For best flavor and vitamin content, plan to use “New Potatoes” immediately after digging.
Dig mature potatoes for storing 2–4 weeks after the plants turn yellow and die back. Use a spading fork and work from the outside edge of each row, turning the soil over carefully so that the potatoes are not damaged. Most of the crop will be in the top 6" of soil. Harvest potatoes on a sunny day and leave them out to dry for an hour.
NOTE: The leaves of potato plants are poisonous to humans and animals.