Just as the move outdoors was traumatic for plants because of the big differences in light and humidity levels, bringing them back indoors can result in yellowed leaves, dieback and wilting. Try for a gradual reintroduction to the indoors before temperatures dip below freezing. (Basil growing outdoors is a good indicator plant, and ours is still green and fresh, so it is not too late this fall!)
First, inspect plants for insects and diseases, and wash with a dilute solution of Ivory Liquid and water, then rinse thoroughly (outside or in the shower). Another option is to spray with an organic pesticide like Safer Soap before bringing plants back inside.
Check the outside of the pot for dirt or signs of unwanted inhabitants. Submerging the entire plant and pot in a tub of room temperature water for about 15 minutes will force insects out of the soil. Snails, earthworms or other insects have got to go. A soaking will also help you scrub the pot clean using a stiff scrub brush.
Second, evaluate your plants from an interior design standpoint. Did they get too big and outgrow the space this summer? Can they be cut back, or divided and shared, to maintain an appropriate size?
Have on hand some fresh potting soil containing slow-release fertilizer, a few large size pots and saucers to choose from, and a long serrated bread knife for root pruning or dividing.
1. Knock the plant out of the pot and evaluate how crowded the roots are. Is there a solid mass of white roots, or can you see some potting soil along the sides?
a. to pot up to a larger size pot
b. to root prune and return the plant to the same pot with some fresh soil (after scrubbing the pot inside and out)
c. to divide in half and replant each half the plant into a pot with some fresh soil (two pots will be needed).
If potting up, add fresh potting soil to the bottom and sides of the larger container and pop in the plant.
If root pruning, slice away about an inch of the solid mass of roots from sides and bottom all the way around, using the long serrated bread knife. Then pot up as described above. Cut back top growth to the desired size using sharp pruners or utility shears.
If dividing the plant in half, shake some of the soil off of the roots and hunt for a natural division through the center of the plant. Use the long serrated bread knife to help saw the crown in half. Then pot up each half as described above, placing each new plant in the center of the new pot and adding fresh potting soil as needed.
Clean your windows (perfect timing for Thanksgiving, too) to ensure that plants will get adequate light through the glass this winter.
Place plants on waterproof saucers in your living space. The key will be to water appropriately, after the soil surface gets dry to the touch for a day or two. Beware! Overwatering is the #1 cause of death of houseplants. Indoors they won't need as much water as they did outside during our dry summer, but after the furnace kicks on, they will dry out a little more quickly. Water succulents and Phalaenopsis moth orchids even less often, when the soil has been dry for several days. Don’t water during dark, cloudy days or rainy weather because plants won’t get sufficient light indoors to dry out.
Of course the other option is to treat houseplants like cut flowers instead of like old friends, and toss them out (or into the compost pile) this time of year and start with fresh, vigorous nursery stock. Which way do you prefer? Let Crabapple know.