Lawn and Garden Shop
Garden Improvement Information Series

Potatoes for Home Gardeners

Potatoes plants (Solanium tuberosum) are an erect South American herb of the nightshade family widely cultivated as an important vegetable crop. The edible starchy tuber is the part of the plant that is eaten. The green leaves and stems are usually quite poisonous to humans, although this condition varies from human to human.

Healthy potato plants are the result of healthy soils and proper environmental conditions. One of these conditions is to pick a garden area with at least six hours of direct full sunshine each day. Eight or more hours is better. Potatoes will grow with less than six, but the yields will be lower.
The required healthy soils is necessary for optimim root, plant and tuber developement. The soil must have a proper balance of numerous enzymes, microorganisms, nutrients, organic matter and a favorable soil pH. Our goal as gardeners is to help establish and to maintain an optimum balance of these factors. This will maximize the nutritional value, quantity, quality, flavor, and appearance of our home grown potatoes.

Soil Preparation

Potatoes like deep, light and loose well drained soil. Most potato varieties form a large root system and require a loose soil for optimum tuber developement. When ideal growing conditions are available potatoes can produce very large yields. However, the pototo is a very accomidating and adaptable plant and will produce quite nicely without ideal growing soil and conditions. All garden soils must however, be loose and drain well so that the pototoe doesn't have to fight just to suvive. While drainage is important, large amounts of organic material should be worked into the soil for moisture holding reasons and nutrients. Potatoes thrive in a soil loosened to a depth of eight inches or more with lots of organic material and humus worked into the soil.
Newly plowed or virgin soil produces some very good yields because of the abundance of nutrients in the soil.
Potatoes do best in a soil with a pH ranging between 5.2 to 6.8. Alkaline soil will tend to make many varieties scabby. Potatoes respond well to an addition of calcium, but don't add agricultural lime to the soil the same year as planting. Scabbing may result. Scab is soil borne, not potato borne. Add powdered Dolimite limestone instead. Although it is best to add the Dolimite at least four months before planting so that the limestone can release it's nutrients so that the pH can change.
If the pH is above 6.2 you may consider adding Gypsum to add calcium also. Add 5 Pounds for 100 square feet of garden area.

Seed Selection
Seed variety selection is the first priority. One must first decide what variety of potato to plant. There are many to choose from. Potatoes are classified by skin and tuber color, texture, and growing time. We will deal only a select few types of pototoes that are grown in the Pacific Northwest. These are varieties of Reds, Browns, Whites, Yellows, and Purples. From this mix we must also decide if the potato variety that we are going to grow is best for baking, frying or boiling.
These are a few varieties that we grow on on our farm.
Baking: Most Russet varieties, Yukon Golds, Würtenburg, Rhineland Golds
Frying: Most Russet varieties, Yukon Golds, Yellow Finns, Rhineland Golds
Boiling: Red Rose, Kennibec, Norland, Nochsack, German Butterballs, most purples

Seed Preparation & Planting
Seed preparation is simply to prepare the whole small pototo or cut the larger potato tuber into two or more pieces. But, first it is best to allow the potatoes to sprout a little. This process is referred to as chitting. Take the potatoes out of storage and spread them out on a flat surface so that they are one potato deep. The temperature should be just below normal room temperatures (55 to 60 ºF). Leave them there for a week or more in the dark. Watch for sprouting. When the sprouts appear, their growth can be controlled somewhat by appling a light source. Letting the sprouts grow to perhaps less than 3/4 inch in longth is fine. But, if the sprouts do grow longer, do not break them off. Instead plant the whole seed potoato with the sprouts turned upward. This chitting process gives the potatoes a week or two head start in the growing season.
Then select whole potatoes that are less than 1 1/4" in diameter with at least two or three good eyes (tiny sprouts). Potato tubers that are larger should be cut into two or more pieces. But here again each piece must have at least two, but no more than three eyes. The cut pieces should be left out to allow the cut to seal over. To do this place each piece in an cool area out of direct sun. Place the cut tubers with the cut side up. Don't crowd the piece, but allow air to circulate around each piece. If time is short, put clean dry powdered Dolomite limestone on the cut to seal it.

When to Plant Potatoes
When the soil temperature has warmed up enough it is time to plant the potatoes.
Generally the proper time to plant early potatoes is four to six weeks before the last frost in the Spring. Mid season and late varieties are planted later. Almost all potato varieties are havested between 14 to 20 weeks after planting. Some Russet varieties, and late potatoes may take longer. This is usually because the tubers are allowed to grow very large.
However, in areas of ample water, fertile soil, and long days of direct sunshine Würtenburg and some varieties of Russet potatoes can grow very large sound tubers quicker.
Keep track of your planting dates, potatoes varieties, and weather conditions each year. This will help you to establish the best planting dates for your area. Then you can make slight adjustments each year as the need arises.

Planting Potatoes
Select each piece of potato seed so that each has two to four strong heathy sprouts. Save only the strongest three, remove any other ones.
Plant each potato seed deep enough so that about 1 1/2 inches of soil is above the seed. (about a 3 inch deep hole) Plant the seed with the eyes upward. Space the potato seeds about one foot to 16 inches apart in a row. Each row should be two feet apart, wider if needed for machinery, running north and south. This alignment will usually give the potato plants a better early start because of the daily sun patterns in most northern areas.

Care While Growing
Potatoes need full sun to develope properly and grow great tubers. And they need lots of water, but do not over water. Potato tubers are mostly water. Be certain that the soil also drains well.
The tiny blue and white flowers will appear about the same time as the tubers start to grow rapidly underground. This is the time hill the potatoe plant by gently pulling the soil up around the potatoe plant to give tubers more soil above their developing tubers. Keep the soil around each plant loose. Watch for tubers poking out of the ground. Exposed tuber's skin will turn green. So to prevent this, potato plants may need to be hilled again. This is done by pulling the loose dirt up around the base of each plant to cover all exposed tubers. But use care, do not cover the growing potato plant's leaves.
Watch for and remove all bugs that love to eat potato plant leaves. This includes a tiny beattle called a leaf hoppers, other bugs and various caterpillars.
Maintain loose soil, remove excess weeds, and bugs. And water your potatoes, best time is the early morning hours. This allows the water on the leaves to evaporate before the sun becomes to hot.

Harvesting and Storage
Once the potato plant's tops have died back, leave the potatoes in the ground for a week or two. This helps to harden their skins for safer storage. Then dig with a four flat tined spading fork. Leave the tubers on the ground in the air to dry. But, use caution that the potato tubers do not freeze. Once dry, don't wash them, but gently brush off the excess dirt.
Sort the potato tubers. Remove all cut or damaged tubers and save these to be eaten first and soon. The remainder are to saved and stored. Then box or sack the potatoes and store in a root celler or another ventilated cool somewhat damp place safe from freezing. Storage temperature should be 38 to 40 degrees Fahrenheit. If the temperature becomes too warm the potatoes may shrivel because of the loss of water.

Seed And Plant Sources

Seed And Plant Sources
We have listed online sources for vegetable and flower seeds, certified seed potatoes, annual and perennial flower seeds, berry plants, fruit trees, live trees, tree seeds & seedlings, heirloom herbs, ferns, mosses and fungi, and other plants. Also includes certified organic and heirloom seed potatoes, garlic, and onions.

Potatoe Varieties

Potatoe Varieties

Utility Links

Thank you for visiting today.

If you have questions, comments, or suggestions please Email us at Mastergardener@homegardeners.com