Potatoes

Selection and Planting

Potato Varieties

Even though potato varieties are broad and vary between starchy and waxy and red and white, they are all grown the same way.  When selecting a potato, determine how you like to enjoy them (baked, mashed, fried, etc) and select a variety that best suits your tastes.  If you aren’t adventurous and would like a good all-purpose potato, Yukon Gold is a staple that performs well.

Some varieties, such as King Harry, have been shown to be resistant to the Colorado Potato Beetle and are worth investigating if you have a problem with that insect.

Planting

Look for reputable seed potato suppliers (Wood Prairie Farms and Johnny’s Seed are two examples) that are certified disease free.  Avoid potatoes found in big box stores as they might not be fresh and have the disease-free certification.  Also avoid potatoes found in grocery stores since they are often sprayed with a chemical that inhibits sprouting.

Seed potatoes are usually small and do not need to be divided.  However, if you receive larger potatoes (greater than 2.5 oz) you should cut them in half with a clean knife a day or two before planting.  Be sure to have at least two eyes per piece.

Seed potatoes should be planted in soil temperatures greater than 50 degrees F which falls around late April.  Rely on the Rose Tree Garden Weather Data for this information.   Potatoes planted into soil colder than 45 degrees are at increased risk of delayed sprouting and rotting.

Space potato plants approximately 12 inches apart and at a depth of 4 inches, but rely on your seed supplier for more accurate guidance.  Place each seed into the ground with eyes facing upwards.  As the potato plant grows in size,  hoe soil in a mound around the plant to keep growing tubers covered.  Exposed tubers will turn green and will become inedible.

Growing Potatoes

Pests

Potatoes can be seriously damaged by insect pests.  Read about the pests listed below and formulate a plan to control these pests as the season progresses.

Diseases

Potatoes can be susceptible to many diseases including verticillium wilt and lead spot.  These diseases generally form on weak plants grown in the same location year after year.  Regularly monitor the health of your plants and be quick to act when issues are discovered.  Below is a list of three steps you can take to improve your chance of growing healthy plants

  1. Plant spacing: Potato plants that are positioned too close together will result in higher levels of humidity near the leaves due to air not being able to move between the plants.  Making sure to give plants plenty of space will improve airflow and reduce the likelihood of disease
  2. Watering: Avoid directly spraying the leaves of the plant as this may increase the spread of disease.  If you must wet the leaves, do so in the morning so the leaves will dry quickly in the sunlight.
  3. Crop rotation: A number of plant diseases come from a slow buildup in the soil over a period of time.  Crop rotation (not growing plants in the same place every year) will keep the amount of soil disease low.  Every year, move your plants to a different part of your garden that has not grown tomatoes, potatoes, peppers, or eggplant in the past 3 years.

Watering

Potato plants demand large amounts of water during the development of the tubers.  Regularly check the moisture levels of the plant through the help of the Rose Tree Garden Weather Data.  Water your plants when the soil moisture decreases or the garden has not received at least 1″ of rainfall in the past week.

When watering, be sure to avoid overhead sprinkling as this increases the likelihood of soil-borne diseases spreading to the plant.  Water slowly at the base of the plant over a period of an hour to encourage deep root growth.  Long and infrequent watering encourages the plant to focus on root development which will enable it to survive through periods of drought. 

Weed Control

Keep area under potato plants clear of weeds to prevent competition.  Because of the mounds of tubers, only hand weeding is encouraged.  Reduce the weed pressure by following our Weed Prevention suggestions.

Harvesting

Potatoes can be harvested at any point in their development.  Small tubers are generally more tender and sweet than full-sized ones.  However, the yield for plants harvested early will be substantially lower.

For fully mature potatoes that you are planning on storing, wait until the above ground foliage has withered and then wait another 2 weeks.  This will allow the skin to harden for increased storage life.  If you are not planning on storing your potatoes, wait until after your plants finish blooming (some plants may not bloom) or when the above ground foliage begins dying. 

Remove tubers by digging them out with your hands.  Use of tools may damage your potatoes.  If you must use tools to loosen the ground, use a garden fork to break up the soil in a ring 1 foot away from the plant.  Slowly move closer to the plant as needed until the potatoes can be removed.  Be sure to remove all potatoes from the area as those that remain could breed disease.

Storage

Potatoes store best in dark moist environments kept between 35 and 40 degrees F.  Rely on the information provided by your seed supplier on how long your specific variety of potato can be stored.