Bringing Houseplants Indoors After Their “Summer Vacation”

Just like us humans, many houseplants enjoy spending their summer vacations outdoors. Bringing your houseplants back inside after a nice summer in the sun can be a rewarding process that allows you to enjoy their beauty year-round. With a little care and patience, you can help them transition their environment and thrive in their indoor habitat during the colder months.

The benefits of outdoor life: 

  • Plants love to go “on vacation” outdoors as much as we humans.   
  • The warm air, refreshing rain and unfiltered sunlight rejuvenates them.   
  • While outside they are able to store enough energy to look good through the winter months.   
  • By early October it is time to get them ready to come back inside.

Fall Curfew is the first average frost date in Chicagoland – October 15th

  • When night temperatures dip below 45F   
  • Most tropical plants will suffer damage when temperatures drop below 40F, a few at 50F  
  • Gradual reintroduction is best because conditions vary widely between inside and outside your home  
  • Sudden changes in temperature, light and humidity can be traumatic  
  • Results are yellow leaves, dieback, wilting or even death 
  • The timing dilemma is controlled by the weather
    • Take advantage of the late warm sunny days as long as possible 
    • For less stress, move plants inside before the furnace is turned on

Frost damage from freezing temperatures.

Get Ready for the Move 

  • Clean the windows – inside and out – to ensure that the plants get enough light. 
  • Re-pot the plants only if they need it 
    • If they grew so much that the pot tips over. 
    • If they are so root bound that you have to water more than 2 times per week to prevent wilting. 
    • Only use sterilized potting mix and clean containers
    • Never increase the pot size more than 2 inches in diameter.
  • Build a wide shelf in front of a window or purchase a plant étagère. 
  • Add ceiling hooks for hanging pots. 
  • Plan to increase humidity around the plants
    • Humidity trays or trays filled with gravel and water 
    • Room humidifier – (even if there is a humidifier attached to the furnace.) 
    • Misting – but you must be compulsive to be effective (some people are, but I prefer the humidifier).

Clean up the plants while they are still outdoors.

  • Wash leaves off with water both upper surfaces and lower surfaces 
  • Inspect leaves for insects and diseases  
    • Use a systemic insecticide in the soil – effects last for 30 days (Bonide Systemic Insect Killer) 
    • Spray with Bio-Advanced 3-in-1 Insect, Disease & Mite Control – Ready-to-Use spray or Ready-to-Spray Hose-End Sprayer. 
    • Spray with Bio-Advanced Rose & Flower Insecticide (RTU – Ready-to-use spray, cleared for use indoors or outdoors – systemic active ingredient stays in plant 30 days) 
    • An organic alternative is to spray with insecticidal soap or a pyrethrin based insecticide – spray 2 to 3 times 2-3 days apart. 
    • The insect treatment should be done one week before the plants come back into the house. 
    •  Just before the move inside, check each plant again to make sure no insects tag along – if still present, repeat the insecticide treatment and isolate the plant. 
    • Check the plant every other day before placing them next to other plants. Check plants weekly to make sure the systemic insecticides are working effectively.
  • Fertilize once more while outside
    • Applying fertilizer is easier when the plant is still outside, take advantage and give the last application before the “dormant“ season 
    • Use a synthetic like Schultz’s Houseplant Fertilizer (with 3 micronutrients) or Dyna-Gro Grow 7-9-5 Liquid Plant Food (with 11 micronutrients)

To Prune or Not to Prune

If the plant has grown too much to fit into it’s former place indoors, go ahead and prune the branches back – but no more than 1/3rd of the branch length - it is better to wait to prune until after winter prior to the next active growth period

Moving Plants Back Inside

To prevent shock when bringing back indoors, expose plants gradually to reduced lighting. 

  •  Realize that shade under a shade tree outside is brighter than a sunny window indoors. 
  •  When light levels are lower, expose plants to lower temperatures to reduce their metabolism – 65 degree temperatures are best. 
  •  Lower temperatures also reduce the risk of mite eggs hatching. 
  •  It’s best if they have been in high light outside to put them in similar light indoors like a south window. 
  •  Use a plant light to supplement low light levels indoors – 16 hours of exposure per day is equivalent to a day of full sunlight. Use a timer for best results.

Plant Lights: 

  • Full spectrum  
  • LED  
  • Run for 16 hours per day to give full sun equivalent  
  • Red light vs blue light effect

Acclimating back to indoors

“Balancing the checkbook” 

  •  Expect some leaves to yellow and fall off   
  •  The ones that formed in the sun will not be as efficient in lower light 
  •  The chlorophyll cells orient vertically in full sun as opposed to  horizontally in shade  
  •  So the plant will form an abscission layer and the leaves will drop off  
  •  Do not worry – new ones will form in the lower light to take their place

Do Not Overwater  

  • Indoors the plants will not require as much water as they did outdoors 
  •  Let the soil surface get dry to the touch before watering again 
  •  Avoid allowing plants to sit in a saucer full of water, this will kill roots. (15 minutes is the maximum amount of time to sit in water) 
  •  Use a turkey baster to suction the water out of the saucer if the plant is too large to lift 
  •  Place the pot on top of 2-3 bricks to elevate the pot above the standing water in a saucer; or use a Down Under Plant Stand set in the saucer to set the pot on. The larger size with the 1 ½ inch feet is best to allow more space for drainage water to keep the bottom of the container out of water 
  •  Water succulents and cactus even less frequently than foliage plants 
  •  If weather is cloudy or rainy, reduce watering as plants will not get sufficient light to need water and the soil will not dry out

Jennifer Brennan

Jennifer Brennan is the Horticulture Information Specialist, advising and coaching gardeners at Chalet for over 30 years.