Potatoes are a fun and interesting food to grow. They are different than most other plants because instead of seeds you plant an actual potato. The potato plant has a lush, green vine that grows above the ground and produces white flowers. Have you ever kept grocery store potatoes a little too long and noticed a small greenish white nub emerging from an indentation or eye in the potato? That little nub is what turns into a potato vine.
The underground part of the potato plant swells into what is called a tuber or the potato as we know it. Many tubers grow on one vine and to get a large harvest you have to keep covering the vine with soil as it grows.
Potatoes need full sun and loose, well-drained soil.
If your soil is full of clay make sure to add compost and lots of peat moss so the vines can grow easily.
Plant potatoes as soon as the soil unfreezes and reaches a 45 degree temperature. Vines can tolerate a light frost but cover them if a moderate to heavy frost is expected.
The seeds you plant are not what you expect to see as a seed. They are called seed potatoes. Some are small and the whole potato can be planted. In most cases your seed potatoes will have to be prepared.
Never use potatoes from the grocery store to plant in the garden. Instead, go to your garden center and get certified seed potatoes. The grocery store potatoes have been treated so that they will not sprout and certified seed potatoes are disease free and should be the only ones you plant.
About 1 or 2 weeks before planting put your seed potatoes in a warm place at about 60 to 70 degrees in bright sunlight to activate sprouting. You can put your seed potatoes in a basket or in egg cartons.
The day before planting you will have to cut the seed potatoes if they are too large to plant whole (smaller than a golf ball) with a sharp knife. Cut a 1-1/2 to 2 inch cube containing at least 2 eyes. Leave your cut potatoes open to the air overnight. A callous will cover the cut part and will prevent the seed from rotting in the ground.
There are two main methods to planting potatoes: the trench method and the mound method.
In the trench method you dig a shallow trench about 4 inches wide and 8 inches deep piling excess soil in ridges on each side. Put a little compost and peat moss in the bottom of the trench. Place seed potatoes cut side down and cover with about 4 Inches of soil. You will still see a depression where the trench is with soil ridges on each side.
Sprouts will appear in about 2 weeks. When they get about 2 inches high (this will take about 3 weeks) add about 3 to 4 inches of soil from your ridges to partially cover the growing vines. When the vines get about 8 inches tall add soil from the ridges half way so that only 4 inches are sticking out from the soil. Do this again 2 weeks later. This process is called “hilling”. Add an inch or two of soil every week so there is enough soil above the developing potatoes to prevent them from sticking out above the soil line because the potatoes will turn green. Some say that green part is toxic.
By the time you are done you will have a long mound in your garden instead of a trench that is covered with potato vines. Stop mounding with soil when the vines bloom.
The mounding method can be done in a small space. Dig out a shallow circle 3 to 4 foot in diameter. Amend the soil with compost and peat moss as done in the trench method. Plant 6 to 8 seed potatoes evenly around the circle and cover with 4 inches of soil. Three weeks later cover vines partially with soil. Proceed as done in the trench method when the vines reach 8 inches high and continue until the vines bloom.
A fun way to plant potatoes is to cultivate and amend the soil in a circle in your garden. Place an automobile tire over the area and place 6 seed potatoes inside filling the tire half way with soil. When the vines grow above the tire, fill with soil partially covering the vines. When the vines grow about 8 inches high place another tire on top and cover the vines half way with soil. Keep adding soil and tires until you reach the desired height. Tires can be stacked 4 to 8 levels high.