Preparation of Seed

Irish potatoes are not grown from seed like most other vegetables. Instead, pieces from the potato itself start new plants. Home gardeners should purchase good seed potatoes that are free of disease and chemicals. Do not buy potatoes from a grocery store for planting.

The seed potato contains buds or “eyes” which sprout and grow into plants. The seed piece provides food for the plant until it develops a root system. Too small a seed piece produces a weak plant. Large seed potatoes for the spring crop should be cut into pieces which weigh about 1 1/2 to 2 ounces (about the size of a medium hen egg). Each seed piece must have at least one good eye (see figure 4). Cut the seed 5 or 6 days before planting. Hold the cut seed in a well-ventilated spot so it can heal over to prevent rotting when planted in cold, wet or very hot weather. Plants killed by a late spring frost will not come back if the seed piece is rotten. One pound of seed potatoes will make 9 to 10 seed pieces.

For fall-grown potatoes, most Texas gardeners plant small, uncut potatoes since they are more resistant to rotting in hot weather than cut potatoes. Potatoes have a rest period which must be broken before they will sprout. The rest period is more easily broken in small, mature potatoes. Select mature potatoes about 1 1/2 inches in diameter for fall planting. To be sure the rest period is broken, store the small seed potatoes under warm, damp conditions for 2 weeks before planting by placing them in a shady spot and covering them with moist burlap bags or mulch. The potatoes should have small sprouts at planting time.

Seed usually is more available in the spring than in the fall. Many gardeners choose to buy extra seed in the spring and hold it over for fall planting. To do this, keep the potatoes in a cool, humid spot such as the bottom of a refrigerator. Do not save your potato seed more than one year. This can cause buildup of virus disease which will reduce yield.

Planting

Potatoes should be planted when the soil temperature 4 inches deep reaches about 50 degrees F, or about 3 weeks before the last spring frost. Potatoes should be planted in February or early March in most areas of Texas. If planted too early the tops can be frozen off by spring frost. For a fall crop, plant about 110 days before the first expected frost, or mud-August in most areas.

Use a hoe or stick to open a trench about 3 inches deep down the center of the bed. Drop seed pieces 10 to 12 inches apart in the trench (see Figure 5). Step on each seed piece after dropping it to assure good contact with the soil. cover the seed about 3 inches deep. If covered too deeply, the plants will be slow to break through the soil and will be more subject to disease and seed decay.

Varieties

The most common type of Irish potatoes are red or white. Most red varieties store longer than white varieties. Most white varieties have better cooking qualities than red varieties. Many gardeners plant some of each in the spring. The whites are used first and the reds stored for later use.