ISSUE 94  |  Change in the Weather

Winter is Coming: How to Keep an Indoor Citrus Tree Happy

October 25, 2013 3:00 PM

BY Michelle Slatalla

Your potted citrus tree does not want to come inside for the winter. I know this because I overheard it talking to its little houseplant friends out on your patio just now. “I don’t like it in there,” it was saying through pursed lemony lips. “If they loved me, they’d get me a heat lamp.” Heat lamp? Lemons do not make much sense when they’re cold. 

You know and I know the tree has no choice; it can’t stay outdoors in freezing temperatures.  On the other hand, your citrus tree isn’t going to like it inside. It is an outdoor plant and will suffer because the air indoors is dry and stale and the sunlight filtered and weak. Unless…

Photographs by Michelle Slatalla.

Step 1: Find a sunny spot. Citrus trees need at least eight hours a day of sunlight to thrive. In the best of all possible worlds, they would get 12 hours a day of sun, but during winter’s shortened days, that is probably not possible. Ideally, you should put your citrus tree in a room with two exposures–eastern and southern, or southern and western are best. In any case, place it in the sunniest spot you have.

 

Step 2: Increase the humidity level. Indoor air is very dry (especially with the furnace on); the humidity level is typically about 10 percent. Citrus trees like 50 percent humidity. To increase humidity, set out bowls of water (this is especially effective if you can set the bowls atop a radiator or in front of a heating vent to increase the rate of evaporation).

Step 3: Improve air circulation. Outdoors, breezes move air around. In airtight buildings, air becomes stagnant. Set up an electric fan in the room where your citrus tree is wintering. On a sunny day when the air temperature outside isn’t too brutally cold, open a window at mid-day for an hour.

Step 4: Give it plenty of water. If the soil gets too dry, salts can build up and damage roots. Keep plants moist (but don’t over water–allow the soil surface to get dry; stick a finger in the soil, and water if it feels dry an inch below the surface).

Step 5: Feed it. A potted citrus tree needs a balanced 18-18-18 fertilizer, applied regularly throughout the year.

Step 6: Get it back outdoors. When the days start to warm up in early spring,  take it outside for an hour or two of sun at mid-day; gradually re-acclimate it to the outdoor world.

Worried your citrus tree will be lonely indoors? Get it a friend to talk to.