Guest Author - Jessica Carson

Potatoes are very easy to grow, and your harvest will last through the winter if stored in a dark, cool and dry location. There are so many varieties or unique and flavorful potatoes available, why limit yourself to just what you can get in the local grocery? And won't your family be surprised when you serve purple mashed potatoes or red cottage fries for the holiday meal! There are just a few basics to follow to ensure a bountiful harvest: seed potato selection, soil, container size, planting, temperature, water and fertilizer, and harvest.

Seed Potato Selection
There are two main differences between seed potatoes and grocery-store (food) potatoes: inspection for disease and purity of strain.
Seed potatoes are grown under controlled conditions and tested to be free of soil-borne diseases. You can be assured that certified seed potatoes will not contaminate your soil or other crops grown with them. Occasionally, seed potatoes are treated to keep them disease and insect free, so you wouldn't want to eat them.
You can also be assured that your seed potatoes are one specific variety, and that your crop will be true to strain and not a hybrid.

The number of days from planting to harvest varies greatly according to potato variety, generally from 65 to 100 days. Be sure to choose a variety which will be ready to harvest before your first frost.

Some growers plant the whole potato (if small), others prefer to cut the seed potatoes into chunks of 2 to 3 eyes each. Either way will work. Some growers recommend that you cut your seed potatoes 2-3 days before planting and let the cut ends dry out, others recommend planting immediately after cutting. I have done both and found no difference in the health of the resulting plant or the yield at harvest.

Soil
Potatoes like a rich loamy soil with a slightly acid pH (around 6.0). A mixture of ½ potting soil, ¼ compost and ¼ fine sand should be ideal. If the soil isn't slightly acidic, add some ground peat moss to bring down the pH.

Container Size
Choose a container large enough that there will be plenty of room for the potatoes to develop underground. A container taller than its diameter is ideal, giving more room for the potatoes to develop along the stem under ground. For most potatoes a 20” diameter tall plastic container will be ideal, and will have enough room for several plants. If you are short on space or only want one plant per container, choose a deep container at least 12” across for small potatoes or at least 16” across for large potatoes. Be sure there are adequate drainage holes in the bottom of the container, and cut more or enlarge if needed. Cover the drainage holes with sections of fiberglass window screen.

How to Plant
To plant, fill your container about 5” deep with your soil mixture. If planting one potato chunk in a small container, place it in the center, then partially cover with soil. If growing several potatoes, evenly space the seed potatoes or cut chunks around on top of the soil, and partially cover. Water lightly.

As the potatoes sprout and the stems grow, gently add more soil around them, leaving some leaves exposed. The potato crop will eventually develop along the stem, so the more stem that will eventually be underground, the better. Continue adding soil and watering in until the soil level is 1 to 2 inches below the top of the container.

Temperature (climate)
Plant your potatoes as early as a week before last frost for early varieties, and as late as 2 to 3 ½ months before first frost, depending on days to maturity for your potato type.

If your summers are particularly hot, position your potatoes so they will receive partial shade at the hottest part of the day. Otherwise, locate your potato pots in an area that will receive at least 8 hours of direct sun a day and where they will stay warm at night. Avoid particularly windy areas.

Water and Fertilizer
Give your potatoes about 1” of water a week. Don't keep them soggy, but don't let them dry out, either. The leaves should be a healthy deep-green color. If they start to look yellow at mid-season, give your potatoes a liquid fertilizer of compost tea or fish emulsion.

Harvest
Towards the end of the season and as your crop matures, your potato plant stems and leaves will begin to turn yellow and shrivel. When the foliage has died back, stop watering your potato plants and let them rest for 1 to 2 weeks. When the leaves are almost completely yellow, your potatoes are ready to harvest.

Pull out the stems and leaves from the base of the plant. Using your hands, carefully loosen the soil and dig around to find your potatoes. If you container is large, remove the soil as you dig and place it in another container.

Spread the potatoes out on a tarp or newspaper in a location safe from rodents, and let them dry out for a few days. Brush off the remaining soil, being careful to not damage the potato skin. Store in a cool, dry place with good ventilation, and your harvest will keep through the winter and into the next year.