The first frost of fall is approaching, and gardeners across northern Indiana are being reminded to protect plants that are especially vulnerable to cold temperatures.
The National Weather Service says frost can develop when temperatures fall below about 36 degrees, particularly in rural areas. A widespread frost becomes more likely as temperatures approach freezing.
For much of north central Indiana, the timing is right for gardeners to begin watching overnight forecasts closely. The average first freeze – when temperatures reach 32 degrees or colder – occurs around October 13 in Goshen, October 15 in Fort Wayne and October 17 in South Bend. (Weather.gov)
Purdue Extension says tomatoes, peppers, cucumbers, squash, pumpkins, eggplant, beans, melons and sweet potatoes are among the most vulnerable vegetables. Even a light frost can severely injure or kill many of these warm-season plants.
Gardeners who want to extend the season should cover tender plants before temperatures fall overnight. Sheets, blankets and commercial row covers can provide protection. Covers should be supported above the plants when possible, and they should be removed once temperatures warm during the day.
Plastic can also be used as a temporary covering, but it should not be allowed to rest directly against plant foliage because the cold plastic can cause additional damage.
Another option is harvesting ripe or nearly ripe tomatoes, peppers and other tender vegetables before the frost arrives.
Not every plant needs protection. Purdue classifies kale, spinach, lettuce, peas, onions, turnips, rhubarb and several other cool-season vegetables as very hardy, while broccoli, cabbage, carrots, cauliflower, Brussels sprouts and radishes can generally tolerate light frost.
Gardeners should also remember that temperatures can vary significantly within a small area. The National Weather Service notes that frost is localized, meaning a sheltered yard may escape damage while a nearby low-lying or rural location experiences frost.
The bottom line for gardeners: check the overnight forecast, protect tender plants before sunset and harvest what you don’t want to lose to the first frost.
