Prepare the soil Use your best method to loosen up the soil 8 to 12 inches deep. Mix in compost or fertilizer if needed. If the soil is dry, water it a few days before planting. It’s best to plant in moist soil, not soaked and wet.
Plant the seed Plant no earlier then 2 weeks before your last frost with a soil temperature above 45° F. If the seed is egg-sized or smaller, you can plant it whole. If it is larger you can cut the potato into egg-sized pieces with one or more eyes on each piece.
Trenching and Hilling Method Make trenches 6 inches deep and 2 to 3 feet apart. The trenches should have a nice bank of soil on each side. A shallower 3-inch trench can also be used but you’ll probably want a larger hill with this one. Plant each seed piece about 12 inches apart. Cover the seed with about 3 to 4 inches of soil.
When the plants emerge in about 2 weeks, you can rake in the bank around the base of the plants. This will fill in the trench and begin forming a nice hill. Be sure there is at least 1 inch or more of plant exposed for growing. In about 2 weeks or when the vines are 8 inches tall, you can add more soil to the hill. Be careful about hilling after 4 weeks because this is when the tubers start to form underground.
Mulching Method: Prepare the soil as mentioned before. Plant the seed pieces very shallow or on the surface of the soil. Cover with 6 to 10 inches of loose straw or hay. When the plants grow out of the mulch, cover with another 4 to 6 inches. Make sure there is enough mulch to keep the sunlight from reaching the tubers. At harvest time, just pull back the mulch to find your nice clean potatoes.
Barrel Method: Place your barrel or wire cage over a prepared bed of soil. Plant about 2 or 3 seed pieces and cover with 4 inches of soil. As the plants emerge and grow, continue covering with mulch or soil. The longer growth will produce more potatoes. If you harvest asparagus that will be consumed later, wash the spears and place the cut ends in about 2 inches of water. Like fresh flowers, they will keep in the refrigerator for several days.
Watering It’s best to plant seed potatoes in moist soil but not too wet. As long as the soil doesn’t completely dry out, it’s good to wait about 2 weeks for the plants to emerge before watering again. That’s when the focus changes from not applying too much water to making sure the soil doesn’t dry out. As the potatoes grow throughout the season, you’ll be able to observe how they use more and more water. When I irrigate, I like to soak the soil thoroughly. Next I’ll let the potatoes drink some of the water and then I’ll check the soil in 2 to 3 days. The soil will go from wet to moist to dry. It’s best to irrigate before the soil gets to the dry level. Potatoes use 1 to 2 inches of water per week.
Water the potatoes as evenly as possible. This helps the tubers to have uniform shape and helps make a better yield.
Stop watering about 2 weeks before harvest or when the vines turn yellow and naturally die after 90 to 120 days. This will help cure the potatoes for harvest.
Weeding Pulling the weeds early in the season will allow the potatoes to take up their space and keep the weeds down after that. Cultivate or hoe the weeds as shallow as possible because this process could damage some of the stolons (underground stems) that make the tubers. For small patches, it’s better to pull weeds by hand, getting them out before they are bigger than the potato vines. Keeping the weeds down allows the potatoes to produce a better crop.
Pests If insects are putting too much stress on the plants, we recommend using organic methods like insecticidal soaps and ladybugs.
Harvesting You can check for new potatoes in about 50 to 60 days or when the plants are blooming. One of my fond memories of childhood is eating new potatoes because they taste so good. Only harvest enough for 2 or 3 days and keep in the refrigerator because these don’t last long.
At the end of the growing season, 90 to 120 days, the vines will die back from age or from frost. Although not necessary, waiting about 2 weeks after the vines die will allow the potato skins to harden. This way you can avoid skinning them during harvest and the potato will also last longer in storage.
Storage The best place to store your potatoes is in the dark with a temperature above freezing. A constant 40 degrees Fahrenheit is ideal and a high relative humidity is best, (85%-90%). Storing potatoes from 34 to 38 degrees helps them last longer. At this temperature, some of the starch in the potato will turn into sugar. It makes the potatoes taste a little sweeter and the sugar is what turns brown when they are fried in oil. Storing potatoes from 40 to 50 degrees helps them keep their starch content and they won’t brown when fried. This is how they are stored for the chipping industry. However, the potatoes won’t last as long when they are stored at 50 degrees.