Moving plants inside after they have grown in the yard all summer poses challenges, but it is not impossible. It does require you to alter your expectations for growth and vigor as inside growing conditions simply cannot match the warmth or the light of the summer sun. Expect plants to cease growth for a short time and to lose some of their summer color, but don't give up on them before they have had time to readjust to the conditions inside the home. With attention and care, plants that spend their summers outside can be brought inside for the winter with only minimal setback.
Begin the process of moving plants inside well before the days grow too cool. If the nighttime temperatures begin dip to 55 degrees or below, it is time to start moving plants inside. Although it isn't cold enough yet for a frost, it is cold enough to stunt their growth.
Move them gradually. If you have a porch or shed, make this a pit stop between the yard and your home. It will provide shelter from chilly winds and cold nighttime temperatures without creating a drastic change in temperature for your plants.
Re-pot them into suitable pots for the home, if necessary. Remove the plant from the existing pot by turning it on its side and tapping gently. Slip the plant into the palm of your hand and shake gently to remove excess soil from the roots. Use care not to damage young roots. Place the plant into the new pot to the original soil line and pack down firmly. Water lightly to create evenly moist soil. Place in a cool area of your home in filtered sunlight to adjust to the inside growing conditions. Gradually move to the desired location, being careful not to subject the plant to a drastic temperature change.
Take stem cuttings from plants that have grown too large to move inside. Simply clip several sections of new growth and place in a glass of fresh water. Sit on a sunny window sill and wait for roots to form. The amount of time it takes will depend on the plant, but most will begin to show roots within a week. Pot in all-purpose potting soil once roots are well formed.
Expect some leaf drop for a few weeks. This is normal; your plant will soon bounce back from the move. Simply discard the leaves and continue to care for the plant as usual.