Choose a potato variety according to your tastes or harvest time. Irish Cobbler and Norland produce early harvests, Red Pontiac and Viking produce midseason harvests, and Katahdin and Kennebec produce late harvests. You may be limited to what is sold at the local garden center, or you may purchase many other varieties from online retailers.
Planting Needs
Before you get started, you will need to pick an area of the garden that gets full sunlight and that has loose or loamy organically rich soil and good drainage. The better the soil quality, the more your efforts will be rewarded. You can amend heavy clay soils by adding mulch, leaves, straw or compost to the area in the fall and turning the soil over for the winter. This is an inviting home for worms that help loosen the soil further and add nutrient rich castings or worm excrement. Turning over a cover crop that was planted in the fall is an excellent way to add nutrients into the soil without using pelletized fertilizers that may send the worms scattering.
Planting
Cold temperatures during early planting may not affect your seed potatoes, but it is best to wait until the seasonal heavy rains have passed to avoid rotting the seed. Initially, your hole should be dug to a depth of one foot and then back filled to 4 to 6 inches. Place the potato or a portion of the potato into the hole, planting potato eyes pointing toward the sky. Space your plantings 12 inches apart and rows 2 to 3 feet apart.
Tending the Plants
When planting seed potatoes, keep in mind that temperature is important for tuber or potato formation. New potatoes will not form if the soil is above 80 °F according to the University of Illinois Extension. Soil temperatures between 60 to 70 °F are optimal. To help keep the soil cool over the hot summer months and to encourage growth of new tubers, you should continue to mound dirt around the growing foliage throughout the season or add as much loose straw as the foliage height will allow. Don’t cover the foliage completely as the plant needs full sunlight to grow properly and feed the tubers. You’ve worked hard in your potato garden – you want as many new potatoes as possible to be produced from each plant.
Harvest Time
Once the foliage dies back in the late summer or fall, it is time to dig up your crop. You will need a spade shovel or spading fork to get down deep beneath the potatoes. Work from the side of the mound inward, never digging directly into the center as you may destroy some of the crop. If you prefer a smaller, ‘new’ potato, dig your mound midway through the growing season. Hopefully your little seed potato has transformed into a 3 to 5 gallon bucket full of mashed-potatoes-to-be for each plant!