Growing potatoes in a home garden can be a rewarding experience, but it comes with its own set of challenges. Gardeners often encounter various problems that can hinder the health and productivity of their potato plants. Learn more about common potato problems home gardeners face, offering preventive measures and management techniques to ensure a bountiful harvest.
Green Tubers | Frost Damage | Potato Scab | Cracks | Raised Spots | Knobby Potatoes | Hollow Heart | Holes in Tubers | Colorado Potato Beetle | Sprouting in Storage | Sugary Potatoes | Tomato-like Fruit | More Information
Green Tubers
Potato tubers are enlarged underground stems. When potato tubers are exposed to light (either in the garden or storage), their skin turns green due to the formation of chlorophyll. The chlorophyll itself is not a problem. However, higher levels of glycoalkaloids also develop in the green tissue. Green tubers have a bitter taste when eaten. They may also cause an upset stomach and more serious health issues. Green portions should be cut off and discarded before boiling or baking the potatoes.
When growing potatoes in the garden, hill the soil around the base of the potato plants to prevent the tubers from being exposed to light. After harvesting, store potatoes in a dark location.
Frost Damage
Potato shoots (stems) are sensitive to freezing temperatures. Symptoms of freeze damage may vary from blackening of the leaf margins (minor damage) to death of all aboveground growth (severe damage). Fortunately, severely damaged potatoes will send up new growth (shoots) within 10 to 14 days. There is no need to replant the potatoes.
Rough or Scabby Tubers (Potato Scab)
Rough, corky patches on the surface of potato tubers are due to potato scab. Potato scab is caused by the bacterium Streptomyces scabies. Though unsightly, scabby potato tubers are still edible. Simply peel the potatoes before use.
Potato scab is most common in alkaline soils (soil pH above 7.0). However, lowering the soil pH is difficult and not practical for most home gardeners. The incidence of potato scab can be reduced by selecting and planting certified, disease-free potatoes in spring. Choose cultivars, such as ‘Superior’ and ‘Red Norland,’ that possess good resistance to potato scab. Also, rotate the placement of potatoes in the garden. If possible, plant potatoes in the same garden area only once every three or four years.
Cracks
Growth cracks typically form when a prolonged dry period is followed by heavy rainfall or irrigation. The rapid uptake of water by the tubers causes them to split or crack. Cracking can be reduced by maintaining an even moisture supply during tuber development. Water on a regular basis during dry periods.
Raised Spots
White, raised spots on potato tubers are due to wet soil conditions. Potato tubers are enlarged underground stems. Lenticels are small openings in the tuber surface that allow for gas exchange. Saturated soils cause the lenticels to swell as gas exchange is impeded. Affected potatoes may not store as long as normal, but are safe to eat.
Knobby Potatoes
Fluctuations in soil moisture levels during tuber development may cause knobby potatoes. Watering on a regular basis, about once a week, during dry periods will help prevent this problem.
Hollow Heart
Large tubers may develop discolored cavities due to rapid growth during the growing season. Remove the discolored tissue; the remainder of the potato is edible. To reduce incidence, avoid over-fertilization of potatoes.
Holes in Tubers
Wireworms (the larvae of several species of click beetles) and white grubs (the larvae of May/June beetles) occasionally feed on potato tubers. Wireworm feeding results in small, round holes in tubers. White grub damage appears as shallow, irregular gouges in tubers.
Wireworm and white grub damage most often occurs in gardens that were lawns or pastures in the previous year. Little can be done to control wireworms and white grubs in home gardens. Fortunately, these insect pests rarely cause widespread damage to the potato crop.
Colorado Potato Beetle
The Colorado potato beetle is difficult to control. Hand-picking is a control option for individuals with small gardens. Hand-pick beetles, eggs, and small larvae from infested plants as soon as possible (practical for a few insects on a few plants, but impractical for larger gardens). Removing overwintering beetles that appear on young plants in spring is especially important.
Learn more in this article: Colorado Potato Beetle Control in the Home Garden
Sprouting in Storage
There is nothing home gardeners can put on potatoes to keep them from sprouting. The keys to successful storage of potatoes are the proper temperature and relative humidity.
Potatoes should be stored at a temperature of 40°F and relative humidity of 90 to 95 percent. Tubers often begin to sprout if storage temperatures are above 50°F. Also, don’t store potatoes with apples or other fruits. Fruits produce ethylene gas. Ethylene promotes the sprouting of potatoes.
Sugary Potatoes
Potatoes stored below 40°F may develop a sugary taste because the respiration rate is decreased more than the conversion rate of starch to sugar. Thus, sugar accumulates in the potato. The sugary potatoes may be reconditioned by placing the potatoes at room temperature for approximately one week. This procedure, however, is not successful for all cultivars.
Tomato-Like Fruit
Gardeners are occasionally surprised to find small, round, green, tomato-like fruit on their potato plants. These fruit are not the result of cross-pollination with tomatoes. They are the actual fruit of the potato plant. The edible tubers are enlarged, underground stems.
Learn more in this article: Tomato-like Fruit on Potato Plants.
More Information
- Growing Potatoes in the Home Garden
- Potatoes (publication)
- Commercial Potato Production Guide (publication)
- Tomato-like Fruit on Potato Plants
- Colorado Potato Beetle Control in the Home Garden
- Vegetable Planting and Harvesting Times
- Crop Rotation in the Vegetable Garden
Photo credits: 1: Aninka/AdobeStock; 2: Sandris/AdobeStock; 3: Viesturs Kalvans/AdobeStock; 4: Nataliia/AdobeStock; 5: Dr. John Meade