AMES, Iowa – Homegrown strawberries are a favorite of nearly everyone, relatively easy to grow and hardy throughout Iowa. Give strawberries full sun, well-drained soils, and with a little care there will be berries to harvest and enjoy. Iowa State University horticulturists answer strawberry pest, disease and harvest questions. To have additional questions answered, contact ISU Hortline at firstname.lastname@example.org or 515-294-3108.
When should strawberries be harvested?
Harvest strawberries when the fruit are uniformly red and fully ripe. Pick the berries with the caps and stems attached to retain firmness and quality. Pinch off the stem about one-fourth inch above the cap. Do not pull off the fruit.
Strawberries should be picked about every other day in warm weather, every three to four days in cool weather. The harvest period for some June-bearing cultivars may last three to four weeks. Strawberries can be stored in the refrigerator for up to five to seven days. Optimum storage conditions are a temperature of 32 degrees Fahrenheit and a relative humidity of 90% to 95%.
Some of the strawberries in my garden are covered with a gray, velvety growth. What is it and how can it be controlled?
The gray, velvety growth on your berries is likely gray mold. It is also known as Botrytis fruit rot. Gray mold is favored by poor air circulation and a high humidity in the strawberry planting. The most commonly infected berries are those touching the soil or other infected berries.
Cultural practices can reduce losses due to gray mold.
- Do not fertilize June-bearing strawberries in spring. The application of a nitrogen-containing fertilizer in spring promotes lush, vegetative growth. Dense foliage slows the drying of the strawberry planting, resulting in a more favorable environment for gray mold.
- Control weeds in the strawberry bed. Weeds reduce air circulation and slow the drying of the strawberry plants.
- Mulch the planting with straw to keep the berries off the ground. Berries resting on damp or wet soil are more susceptible to gray mold.
- During dry weather, irrigate in the morning when using a sprinkler. Plants dry quickly when irrigated in the morning.
- Harvest the strawberry planting frequently. Pick berries as soon as they ripen. Handle berries carefully during harvest to avoid bruising the fruit.
- Immediately refrigerate the unwashed berries.
- Berries that exhibit symptoms of gray mold should be picked and removed from the bed.
- Fungicides are sometimes used by commercial strawberry growers to control gray mold. However, fungicides are not a viable option for home gardeners.
My strawberries aren’t as sweet as normal. Why?
The flavor of most fruits and vegetables is influenced by weather conditions. In regards to strawberries, warm sunny weather produces the most flavorful fruit. Strawberry plants produce smaller quantities of sugars when the weather is cool and cloudy. As a result, berries are not as sweet when the weather is cool and rainy in May and June. When the weather is extremely hot, the berries may have a slightly bitter taste.
There are small, black, yellow-spotted beetles feeding on my strawberries. What should I do?
The small, black beetles are likely sap beetles. They are also known as picnic beetles or picnic bugs. Sap beetles commonly feed on overripe or damaged fruits and vegetables in the garden.
Sanitation is the best management strategy for sap beetles in home gardens. Keep the strawberry patch as clean as possible through timely picking and removal of damaged, diseased and overripe fruit.
Insecticides are not a viable option for gardeners as few insecticides are labeled for use on strawberries in home gardens.
Photo: Strawberry growing on plant by kellyvandellen/stock.adobe.com.