Potatoes are easy to grow organically.
Plant potatoes in spring raised beds or mounded beds after the soil warms and dries out. Plant potatoes where they will grow in full sun.
To prepare potato planting beds, remove large stones and then add an inch or two of aged compost and well-rotted manure. Compost will provide all of the nutrients potatoes require.
Start potatoes from “seed” potatoes—which are not actually seeds, but small potatoes or pieces of potatoes. Use seed potatoes that are certified disease-free. Seed potatoes that are about the size of an egg or smaller can be planted whole. Larger seed potatoes should be cut into egg-size pieces—called sets–with two or three eyes (sprout buds) per piece. Cut pieces should be dried a day or two before planting.
Sowing: Sow seed potatoes when the soil temperature is at least 55°F but not greater than 70°F—usually 2 to 4 weeks before the last frost. Sow seed potatoes in a trench about 6 inches deep. Space pieces 12 inches apart in rows 24 to 36 inches apart. If you plant sets, place the cut side down with the eyes facing up. Cover the seed potato with 3 inches of soil, but do not completely fill in the trench.
Growing: When potato seedlings are about 6 to 8 inches tall, begin to fill in the rest of the trench—use a hoe or spade to push soil into the trench hilling up soil around the plant covering half of the new growth or more. Continue to do this every couple of weeks until you fill in the trench. When the trench is re-filled with soil, mound compost, straw or hay mulch around the plant as it continues to grow—forming small hills around each plant. Hilling up or covering potatoes is important because it keep sunlight from reaching the developing tubers. Tubers exposed to light will turn green and be inedible. As you mound up, more tubers will grow underground increasing your yield. Never fully cover the plant; always allow the top two or three sets of leaves to be fully exposed to sunlight.
More tips: How to Grow Potatoes.
If your garden beds are poor or rocky, you can actually grow potatoes on top of compacted soil by simply placing your seed potatoes or sets on the planting bed and cover them with compost or mulch 6 to 12 inches deep. Instead of trenching, just add mulch as the plant grows. You can also grow potatoes in a plastic trash can on your back steps. Just poke hole in the container, add some soil to about one-third deep, then cover your seed potatoes with 2 inches of soil and “hill-up” in the container just as you would outdoors.
Where there is little rainfall, keep the soil in potato planting beds just moist—not wet. Too little water can result in scablike lesions on the skin of potatoes. Too much water can result in wilt or leaf diseases. Using compost and mulch around potatoes helps regulate water.
Pests and Disease: Keep an eye out for Colorado potato beetles. The black and yellow striped beetles and their larvae can defoliate potato plants. Pick off beetles, larvae, and crush the small, yellow eggs that may be found on the undersides of leaves. Potatoes can suffer from a disease called late blight resulting in soggy, brown leaves. Using certified seed potatoes and disease-resistant varieties should keep diseases away from your potato plants.
Harvesting: The potato harvest can begin seven to eight weeks after planting when the plant begins to blossom. Potatoes harvested at this time are called “new potatoes”—these tubers are small. Full-size tubers can be harvested when the plant begins to wither and turn brown. The number of days to harvest for mature potatoes depends on the variety you grow.
Potatoes are often described as early, midseason, and late. Early-season potatoes are ready about 60 days after planting; midseason about 80 days after planting; and late 90 or more days after planting.
Harvest potatoes when the soil is dry—to avoid compacting the soil as you work in the garden. Use a spading fork to lift the tubers; lift from a foot to a foot and a half or more away from the plant to avoid injuring the tubers—loosen the soil and lift. Let tubers air dry for a couple of weeks to toughen the skin and then brush away any excess soil before you store them. Any potatoes with damaged skins should be used right away; they will rot if you try to store them.
Storing: Store potatoes in a dark, cool place at 35° to 45°F. Store potatoes in a bin, basket, or mesh bag that allows for air circulation.
Varieties to Grow: Here are potato varieties to grow in a home garden:
- All Blue: midseason; use mashed, steamed, roasted, and in salads.
- Butte: early season; baking.
- Caribe: early season; drought tolerant; all-purpose use.
- Carola: late season; yellow flesh; all-purpose use.
- Cranberry Red: early- to midseason; use mashed, steamed, roasted, and in salads.
- French Fingerling: late season; use roasted, baked, and in salads.
- Katahdin: midseason; use French-fried, baked, mashed, or roasted.
- Purple Peruvian: late season; use roasted, baked, and in salads.
- Red Gold: midseason: all-purpose use.
- Red Norland: early season; use boiled, steamed, mashed, or in salads.
- Red Thumb: early season fingerling; roasting.
- Rose Finn Apple: late season; all-purpose use.
- Russian Banana: late season; use roasted, baked, or in salads.
- Yellow Finn: midseason; all-purpose use.
- Yukon Gold: early season; use boiled, mashed, or in salad.