The attention of many gardeners has been on the outdoors for the past several months. But while we were planting flower beds and vegetable gardens, houseplants did their thing, too. They grew.

That means they deserve a close look to see if it is time to move them to roomier quarters in a larger pot where roots can continue to expand more evenly.

This is especially true of the such popular, vigorous houseplants as philodendrons, tropical ferns, grape ivy, peperomia, pothos, begonias and peace lily. All of these remarkable plants do very well in homes, even in rather dim light. Perhaps you are surprised that they seem to have grown so much since early spring, when you either bought them or gave thanks that they survived the winter.

Look for two indications that a houseplant is ready for transplanting. One is rapid wilting of the foliage, the second, roots growing out of the holes at the bottom of the pot. Do not hesitate to repot a plant showing either of these conditions. You will need a pot that is 1 to 2 inches greater in diameter and fresh potting soil. Look for the type that has granules of fertilizer.

Put down newspapers or a plastic sheet to catch the mess that occurs with such a job. Take the plant out of the pot gently by tipping it and letting it slide out. If it resists, slide a knife around the inside perimeter of the pot to loosen the roots and encourage an easy exit.

Once out you may see a lot of wound-up roots around the outside of the root ball. This is a clear sign the plant requires repotting now. Loosen these roots by gently pulling them away from the root ball. Shake off any excess soil.

Before you put soil in the larger pot, cover the drainage holes at the bottom with bits of broken pottery. This keeps soil from washing out of the pot and aids drainage.

Add enough soil so the plant will sit with the top of the root ball about 1 inch from the top of the rim. Add soil around the root ball, shake the pot to settle it and check to see that it is full. Water the plant so soil will settle nicely and then check to see if more soil is needed.

Pay close attention to watering as the plant adjusts to its roomier home.