Here are a few tips for growing potatoes from the Lincoln County Master Gardeners.
Potatoes do best in full sun. They produce a large number of roots on which the new potatoes grow so they need the energy from the sun. They also want to grow in very loose, well draining soil. This ensures the roots stay hydrated without getting soggy.
Soil PH. Potatoes grow best in soil in the midrange of the PH scale, between 5.0 and 7.0. Potatoes are pretty adaptable and will produce a good crop even if the soil and growing conditions are less than optimal. Always keep the potato patch weed-free.
Rotate every year. To reduce likelihood of disease, rotate the location of the potatoes every. Some experts suggest using a 3-4 year cycle until planting in a previous location.
When to Plant
Potatoes can be planted in early spring as soon as the ground can be easily worked. The soil should be around 45 degrees; any colder and the plants won't grow and ma rot out before the soil warms up. They can tolerate a light frost, but it is best to provide some cold protection, especially if a hard frost is predicted.
Preparing the Seed Potatoes
A week or two before planting, set the seed potatoes where they will get light and where the ambient temperature is at least 60 degrees. This will begin the sprouting process. A day before planting, use a sharp, clean knife to slice the larger seed potatoes into smaller pieces. Each piece should be approximately 2" and must contain 1-2 eyes or buds. Smaller potatoes can be planted whole. A good rule of thumb is to plant potatoes whole if they are smaller than a golf ball. In a day or so the seed will form a thick callous over the cuts which will help prevent rotting. i
Planting the Potatoes
Potatoes are best grown in rows. Dig a trench that is 6"-8" deep. Plant each piece of potato, cut side down, with eyes pointing up, every 12-15". Rows should be spaced about 3 feet apart. If space is limited the spacing can be decreased, especially if growing only baby potatoes.
Fill the trend with 4" of soil. Let the plants start to grow and then continue to fill in the trench and mound the soil around the plants as they continue to grow. Prior to planting make sure to cultivate the soil one last time. This will remove any weeds and loosen the soil to allow the plants to establish more quickly.
Keep the potato vines well watered throughout the growing season, especially during the period when the plants are flowering and immediately following the flowering stage. During this time, the plants are creating the tubers and a steady water supply is crucial to good crop production. Potatoes do well with 1-2" of water/rain per week. When the foliage turns yellow and begins to die back, discontinue watering. This will help start curing the potatoes for harvest time.
Baby potatoes can be harvests 2-3 weeks after the plants have finished flowering. Gently dig around the plants to remove potatoes for fresh eating, being careful not to be tool intrusive. Try to remove the biggest new potatoes and leave the smaller ones in place so they can continue to grow. Only take what is needed for immediate use. Homegrown new potatoes are a luxury and should be used the same day as harvested.
Potatoes that will be stored should not be dug until 2-3 weeks after the foliage dies back. Carefully dig potatoes with a sturdy fork and if the weather is dry, allow the potatoes to lay on the soil, unwashed, for 2-3 days. This curing step allows the skins to mature and is essential for good storage. If the weather is wet during harvest, place the potatoes in a dry protected area like a garage or covered porch.
The best storage location is a well ventilated, dark, and cool space. The ideal temperature is between 35-40 degrees. Some varieties are better for storage then others. Carola and Russets are particularly well suited for storage.
Save the best potatoes for planting. After several years of using saved seed potatoes, the size at harvest will start to decrease. Potatoes are also susceptible to viruses. For best maximum yields, it is wise to start fresh with new seed potatoes every couple of years.