Growing the right variety is important and the best in red-skinned varieties are LaSoda and Pontiac and for the white-skinned its Kennebec although it is hard to beat the Yukon Gold. The only problem with specific varieties is that often they are only sold at Minnesota Blues or Nebraska Reds so when faced with this problem be sure to buy the blue certificate seed potatoes. Remember that seed potatoes are only for planting and table-stock potatoes are for eating. Seed potatoes have fungicides to prevent diseases and many table-stock potatoes are treated with sprout inhibitors to keep them from sprouting in the store.
When to plant is always controversial. The books generally recommend that you plant potatoes 4 weeks before the last killing frost. Our last frost can be anytime in February or March but generally if you will plant your potatoes around the middle of February you will do okay. Potatoes grow and do best when temperatures are 60⁰-75⁰ in the day and 45⁰ - 55⁰ at night. Potatoes must set and size their crop before soil temperatures reach 85⁰ the temperature at which potato initiation ceases.
Potatoes are heavy feeders and require high fertility to produce the yield and quality of tubers that you expect. Unlike most vegetables you should work all the fertilizer into the soil before planting. Side-dressing with fertilizer after the plants are up has little effect and may grow more top than tubers. Generally you need 3 pounds of 10-20-10 per 35 foot of row.
When you go to buy seed potatoes it is recommended that you avoid buying seed pieces and only buy whole seed potatoes. Cut the potatoes into 2 to 3 ounce pieces with 2 to 3 eyes per piece. Purchase and cut up your seed potatoes 5 - 7 days before you want to plant. After cutting treat the pieces with sulphur to help prevent soil-borne disease problems. Allow the cut pieces to cure at approximately 65̊ for the 5-7 days at a high humidity. To do this put them in a box in the garage with wet burlap covering the pieces.
At planting time you will notice the pieces are a bit shriveled, have a healed cut surface and slightly enlarged eyes.
Plant the pieces either flat or in a bed 2 ½ to 3 inches deep and spaced 8 to 12 inches in the row. It doesn’t matter how you put the pieces in the furrow they will grow. If you plant more than one row make the rows at least 30 inches apart.
Potatoes will start growing by putting up a main stem which grows upward emerging from the soil to become the plant foliage. Along the underground portion of the main stem, stolons will grow which are like underground stems not roots. These grow laterally for short distances and then begin to enlarge to form the tuber. Since all underground stolons are going to initiate between the seed piece and the soil surface the deeper the seed piece (within reason) the more stolons produced. It is very important to begin to “dirt in” your potatoes when they reach 5 to 6 inches in height with 3 to 4 inches of soil. The ultimate goal is to eventually bury the seed piece 8 inches underground and so have lots of room for stolons and finally potatoes. Why don’t we just plant the seed pieces that deep to begin with? Well sometimes it works fine but if it is cold and wet, soil-borne diseases will get your plants every time simply because it’s too hard for the small plant to push through that much dirt.
Enjoy your red potatoes and fresh green beans, there aint much better eatin’!