How Many Seed Potatoes Do I Need?
Potatoes in a Pound:
As an average in one pound of seed potatoes, you will receive from 5-8 tubers. You can plant all the tubers whole. Or to get more plants, you can cut a few of the larger ones so that you have at least one eye on each piece.
Cutting Seed Potatoes
All tubers the size of a hen’s egg (1-3 oz) may be planted whole. For larger tubers, cut the potato using a clean, sharp knife so that each piece will contain one or more eyes. Pieces should be cut with plenty of flesh around the eyes, since the plant will utilize this stored food during the first 2-3 weeks of growth. If the variety has many eyes, try for two or more eyes on each piece. This provides opportunity for more vines to grow and thus yield more potatoes.
Seeds may be planted immediately after cutting if you have good control of soil moisture. If there is a chance the soil may be too wet for a long period of time, you will want to allow the cut pieces to dry out prior to planting. Spread them out on a table in the shade or one layer deep in shallow boxes for drying. Avoid shriveling which may weaken the seed piece. Also recommended for wet soil conditions is the application of sulfur or Fir bark dust to the freshly cut pieces. Place one or more tablespoons in a large paper bag, and toss the pieces around to cover them with dust. This may guard against threat of infection by bacteria and fungus in wetter soil. If you are able to plant cut seed successfully, then there is no reason to go through the extra steps of drying and dusting.
The rule of thumb to follow, for the earliest planting time, is to plant 2 weeks before your last spring frost. Then of course, you can plant anytime after that, giving yourself at least 3 months growing season before a major fall frost. Some growers plant later than this for better growing temperatures. A good beginning soil temperature to plant in is 50 degrees Fahrenheit.
The width between rows is determined by the size of the garden and method of cultivation. Farmers need 30-36” between rows, while gardeners can get by with 20-26”. You might adjust your spacing to suit adverse conditions. Wider spacing can help alleviate stress due to drought or poor soil. Tighter spacing may give you a uniform canopy of foliage to cool the soil in summer.
Dig a shallow trench about 6-8” deep. Plant your seed potatoes about 12” apart. Using a rake, cover the seed pieces immediately after planting. Do not cover too deep, 4” maximum, and leave the remaining soil for later.
In approximately 2 weeks, depending on soil temperature, green leaves will emerge. When the plants have grown to about 8” high, gently ill with soil brought up from both sides of the plant using a dull hoe. Bring the soil up about 3” leaving 4-6” of the plant exposed. Hilling cools the soil and creates space for tuber development. All tubers will form at the same depth of the seed piece and higher. Another hilling of 1-2” is beneficial 2-3 weeks later. Keep the blade of your hoe well away from the plants so you do not damage the roots. If you see potatoes poking out of the hills, add more soil to cover them.