Why Are My Strawberries Rotting on the Vine?
Strawberries (Fragaria spp.), which grow as a perennial in U.S. Department of Agriculture plant hardiness zones 3 through 10 and as annuals elsewhere, don't usually require much care to produce tasty, juicy fruit. However, the plants and the fruit are susceptible to damage from several sources, including neglect.
Too Long on the Vine
When the strawberries start to mature, pick the ripe ones every two to three days. The harvest season typically lasts about three weeks, but during that time, you must get the ripe fruit off the vine before it starts to rot so it doesn't encourage disease throughout the plants. Pick the berries by snapping them off at the stem instead of pinching the berries below their green leafy caps. Any pieces of berry left on the plant will rot quickly, and the rot can spread to other parts of the plant.
Several types of insects enjoy strawberries almost as much as you do, including slugs, tarnished plant bugs and strawberry weevils. Some of these bugs attack the leafy parts of the plant while others go for immature or mature berries, stunting their growth or damaging the integrity of the fruit. When the berries are damaged in any way, they're more likely to rot. If you see a large number of rotten berries when you try to harvest, look for signs of insect infestation such as slug slime trails, berries barely hanging on to their stems or misshapen or brown fruit.
Fungus Among Us
Several types of fungus invade strawberry plants, including the fruit. This is more likely when the soil stays too moist, which encourages fungal growth. Botrytis fruit rot, for example, often sits dormant on your berries until they are nearly mature, and it makes the fruit squishy and fuzzy on the outside. Also called gray mold, this is worse in fruit that touch the ground where the fungus has easy access. Leather rot also starts in strawberries that touch the ground, then spreads to other areas of the plant. It causes berries to turn brown or look bleached out and feel hard.
Correcting your harvesting timeline is the easiest way to prevent rot; spend a few minutes every other morning picking some strawberries, then put them in the refrigerator until you can clean and eat them. They'll stay fresh in the refrigerator for two to three days, typically. Buy plants certified as disease-free from reputable growers and don't plant strawberries near areas where you've had problems with fungus and insects recently. Although the plants are perennial and can come back for many years, rotate the location every three to four years to help prevent fungus and insects from finding your crop.
- Old Farmer's Almanac: Strawberries
- National Gardening Association: Care and Harvest of Strawberries
- University of Missouri Extension: Home Fruit Production -- Strawberry Cultivars and Their Culture
- North Carolina Cooperative Extension Service: Strawberries in the Home Garden
- University of Georgia: Home Garden Strawberries