One of the most popular vegetables in the home garden is the "Irish" potato. A native of South America, the potato didn't become an important food crop until it was introduced to Ireland in the sixteenth century.
Potatoes prefer loose, fertile, slightly acidic soils. Don't apply large amounts of organic matter, such as barnyard manure, to the soil where potatoes are to be grown. The addition of organic matter may increase the occurrence of potato scab. If a soil test has not been conducted, an application of 1 to 2 pounds of an all-purpose garden fertilizer, such as 10-10-10, per 100 square feet should be adequate for most home gardens. Broadcast and incorporate the fertilizer shortly before planting.
Since potatoes are susceptible to several serious diseases, buy certified, disease-free potatoes at garden centers and mail-order nurseries. Potatoes that remain from last year's crop may carry undetectable diseases. Potatoes purchased at supermarkets (for table use) may have been treated to prevent sprouting. Best results (excellent quality and high yields) are obtained from certified seed potatoes. Gardeners can purchase seed pieces (tubers that have been cut into sections) and whole potatoes. Small potato tubers may be planted whole. Large potatoes should be cut into sections or pieces. Each seed piece should contain 1 or 2 "eyes" or buds and weigh approximately 1.5 to 2.0 ounces. After cutting the tubers into sections, place the freshly cut seed pieces in a humid, 60 to 70 degree Fahrenheit location for 1 or 2 days. A short "healing" period allows the cut surfaces to callus or heal over. Callused seed pieces are less likely to rot in cool, wet soils.
Potatoes should be planted in early spring. The appropriate planting time varies from early April in southern Iowa to mid- to late April for northern portions of the state. Plant seed pieces (cut side down) and small whole potatoes 3 to 4 inches deep and 1 foot apart within the row. Rows should be spaced 2½ to 3 feet apart.
Suggested potato varieties (cultivars) for Iowa include:
- 'Red Norland' is an early maturing red cultivar that produces oblong, smooth potatoes with shallow eyes. They are excellent boiled or mashed, but are only fair when baked.
- 'Red Gold' is an early season cultivar with light red skin and yellow flesh. The tubers are excellent for baking and boiling.
- 'Yukon Gold' is an early season yellow-fleshed cultivar. They are excellent baked, boiled, or mashed. The potatoes also store well.
- 'Russet Norkotah' is an early season russet cultivar that produces blocky, oblong potatoes. It is an excellent baking potato.
- 'Superior' is an early to mid-season cultivar with round to oblong tubers and medium deep eyes. The potatoes are very good baked, boiled, or mashed. It is resistant to scab.
- 'Goldrush' is a mid-season cultivar that produces oblong to oval tubers with a russet skin and white flesh. Baking quality is very good.
- 'Katahdin' is a late maturing white cultivar that produces smooth, round, shallow-eyed tubers. They are excellent for baking.
- 'Kennebec' is a late maturing white cultivar with block-shaped tubers and shallow eyes. Cooking quality is excellent.
- 'Red Pontiac' is a late maturing red cultivar. Potatoes are oblong with deep eyes. It produces high yields with many large tubers. Table quality is only fair. Storage quality is very good.
While the standard potato cultivars listed above perform well in Iowa, there are other cultivars with unusual colors and shapes. For example, 'All Red' is a mid-season cultivar that produces medium-sized tubers with a red skin and pale pink flesh. 'Russian Banana' produces small, banana-shaped tubers which are excellent in salads. The oblong tubers of 'Purple Majesty' have purple skins and flesh. Heirloom and novelty cultivars are tasty and fun additions to the vegetable garden.