Coleus during the winter
During the winter, when it gets darker, your coleus go into dormancy and the plants therefore no longer need as much water and any extra plant nutrition. Prepared by cutting back your large plants a but in autumn to reduce the leaf mass. We usually do it around October.
The most important thing is not to water too much. Feel the pot with your finger, it must be dry before you water! If you have pots with holes in the bottom and barrels, you can water from below. Pour water on the dish and let the plant soak up as much as it wants and pour out the rest of the water from the dish.
Place your coleus plants in your lightest window. Remember not to place the plants directly above a radiator because the air can become too dry and make sure that the leaves do not touch the cold window. Expect your plants to become paler in color and lose leaves. So it's nothing you need to worry about. The coleus plants will be beautiful again as soon as the light returns!
Good luck!