Planting & timing · Oct 6, 2026 · By Nell Harding
Bring Your Potted Citrus In Before Nights Drop Below 50
A lemon or lime tree that spent the summer on the patio has to come inside before the cold nights do. Extension horticulturists give a clear number for when, a gentle way to make the move, and the one indoor mistake that makes citrus drop its leaves.
All summer the lemon tree on the patio soaked up the sun. Now the nights are getting cool, and a potted citrus tree is not built for a northern winter outdoors. The question is when to bring it in, and how to keep it happy once it is inside.
THE NUMBER TO WATCH
Aaron Steil and Cynthia Haynes of Iowa State University Extension and Outreach give a simple rule: in the fall, move citrus indoors once nighttime temperatures drop below 50 degrees Fahrenheit. Temperatures below 50, they note, can cause leaf loss.
That is well above the damage line. Christa Carignan of University of Maryland Extension says most types of citrus will be damaged when the temperature drops below 32 degrees, which is why winter protection is essential. Waiting for the first frost is waiting too long.
MAKE THE MOVE GRADUALLY
Carignan advises acclimating the plant gradually whenever you move it outdoors or indoors.
Kym Pokorny of Oregon State University Extension describes how: put the tree outside during the day and bring it back inside at night for several days. Avoiding sudden temperature swings, she says, is part of keeping citrus healthy. In the Pacific Northwest, her rule of thumb is to bring plants in around Halloween.
FIND IT A SUNNY SPOT
Citrus wants as much light as you can give it indoors. Iowa State says all citrus prefer bright, direct light through fall and winter, and that a west or south-facing window with at least 6 to 8 hours of direct light is often required.
Carignan says a position near a south-facing window provides the strongest winter light.
Mind the temperature as well. Iowa State says citrus prefers 65 to 85 degrees during the day and 55 to 65 at night. Pokorny adds a warning to keep the tree away from heater vents and blasts of hot air.
GO EASY ON THE WATER
The most common indoor mistake is kindness with the watering can. Carignan says to take care not to overwater citrus indoors, and to check the soil moisture once or twice a week. Leaf drop, she notes, is an indicator of overwatering.
Iowa State puts it as a balance: citrus insists on moist but well-drained soil. Too much water and the roots rot. Too little water and the plant starts dropping leaves.
Pokorny's test is easy to remember. In winter, water less often, and check by pushing a finger into the soil up to the second knuckle before you water.
THIS WEEK
Check the night forecast. When it shows lows under 50, start bringing the tree in at night, find it the sunniest window in the house, and let the soil tell you when it needs a drink.
