University of Illinois Extension

Preparing Strawberry Gardens for Winter

Strawberry plants must be kept healthy in the fall as this is the time when new flower buds that will bear fruit next year develop in the crown.

“Proper fertilization and watering is very important in ensuring optimal foliage growth in strawberry plants,” said Maurice Ogutu, U of I Extension horticulturist.

It is also important to control diseases such as leaf spot which can reduce the ability of the plant to produce more foliage.

“Strawberry plants need nutrients such as nitrogen to keep up with growth and the initiation of flower buds,” Ogutu said. “Apply nitrogen fertilizers such as 10-10-10 on bearing beds in early September at the rate of three pounds per 100 square feet. In a renovated strawberry patch, it is advisable to apply about two pounds of 10-10-10 per 100 square feet at renovation time and another one pound in September to stimulate root growth and promote flower bud initiation.”

High analysis nitrogen fertilizers such as ammonium nitrate (35 percent N) may also be considered for application in the fall.

“Weeds should be controlled by cultivation and hand weeding,” he said. “You can hand pull big clumps of crabgrass or other grass weeds in the patch. If there are too many weeds in the patch, you may consider using herbicides recommended for strawberry weed control.
“You can also try to do spot spraying of weeds that are scattered in the patch but remember to follow label directions.”

Home gardeners should also check for aphids and leaf hoppers and, if there are too many, control them with recommended insecticides.

“Aphids need to be controlled because they carry virus diseases and the winged ones can disperse very quickly in the patch,” he noted.

Diseases such as leaf spot and powdery mildew can be controlled by using recommended fungicides and picking off and destroying infected leaves.

“If you have a red stele problem because of heavy rainfall during the summer, consider applying systemic fungicides such as Ridomil Gold or Alliete when the soil begins to cool in late September to early October but before the heavy rains,” he said.

As the days become shorter and colder temperatures occur, plants need less water in order to start developing tolerance to cold temperatures.

“At this time, the plants need to be mulched with three to four inches of straw after a two-to-three-day hard freeze occurring in late November or early December,” said Ogutu. “The straw must be free of weed seeds and not treated with herbicides.

“Since raised beds get colder than flat beds in the winter, they need much more straw mulch for winter protection compared to plants grown on flat beds.”