The fall gardening season has already started and some of the activities which need to be taken care of are bringing houseplants back indoors, potting up summer annuals for extended blooming, and preserving tender bulbs for next year's garden.

Immediate attention should be given to houseplants. They should be moved indoors before they are subjected to cool nights. Many of these plants are of tropical origin and can be set back if exposed to cool weather. Now is also a good time to see if any of your plants have outgrown their pots. If the roots are growing out of the drain holes, it's time to repot.Take into consideration the type and size of the new pot and the growing medium when repotting. The size of the new pot must be bigger than the old pot, but not too large.As a rule, the new pot size is the next larger size. For example, a plant in a 4-inch pot would be repotted in a 5-inch pot. If the new pot is too large, the larger amount of soil will hold a greater amount of water than the plant can use and the fine hair roots can suffocate.An inch difference in the size of the pot makes a significant difference in the amount of soil it will hold. A 5-inch pot holds twice as much and a 6-inch pot 3½ times as much as a 4-inch pot.

A cardinal rule is to never use garden soil to pot or repot a houseplant. Garden soil will become too hard and it also can contain weed seed and larvae of insects. There are a number of good potting mixes available in garden stores.There are three types of pots available — plastic, clay and glazed ceramic.Clay pots are good for almost all plants as they allow water to evaporate through the sides. They are also ideal for plants that need dry soil such as cacti.Plastic and glazed ceramic pots hold water and are best for water-loving plants such as ferns.Make sure to check for insects before bringing indoors. Spraying the plant with insecticidal soap or a household type insecticide should eliminate insects.

Summer bedding plants such as impatiens can be potted up at this time and brought into the house. They will bloom throughout the winter if set in a cool area with adequate sunlight.Let those beautiful hanging baskets of begonias remain outdoors as long as possible but bring them in before they are killed by frost. The foliage should ripen off before storing the bulbs.Flowering will decrease, but the bulb will increase in size. The longer the plant can be kept growing, the larger the bulb will become.Once the foliage has died, remove it from the bulb and store them in a cool area in peat moss in a plastic bag.

It is possible to increase the number of begonia plants next year by cutting the bulbs into several pieces.To do this, replant the stored bulbs in late February or early March. Plant the bulbs, barely covered, in peat moss or potting soil and place in a warm environment. In a few weeks, small pink eyes will develop. Those eyes are the same as sprouts that develop on potatoes.Begonias and potatoes are both tubers and not true bulbs. To increase your yield, cut the tuber into pieces with one eye in each cut section. Replant the cut sections into individual pots.As the new plants grow, they can be repotted into hanging baskets or larger pots. With adequate light they should be in bloom or bud when set outdoors about the middle of May.