One-inch wooden blocks spaced along the cold-frame wall raise the muslin cover enough to allow the necessary fresh air to circulate for ideal growing conditions.

   A lath house can provide ideal summer conditions for all house plants. Such structures are made of narrow wooden slats placed closely enough to keep direct sun off the plants below them. They can be of any size, free standing, attached to a building, or even portable. To create a shadier atmosphere, inexpensive reed screening is sometimes used instead of the typical laths or slats.

   My portable lath house was designed for utility, but when it holds plants, there is beauty too. This small shelter is 33 inches high, 36 inches wide, and 10 feet long. It is made of V4-inch strips ripped from a 10-foot redwood plank 1% inches thick and 6 inches wide. The strips are spaced three quarters of an inch apart on the top and three sides. I cut the legs from redwood two-by-fours, the cross members from one-by-fours. This structure is easily moved and will supply ample shade for even the most delicate plants.

   A larger lath house might include an exciting collection of plants, including aeschynanthus, achimenes, columnea, plec-tranthus, hoya, Campanula isophylla, orchids, anthuriums, cala-diums, all kinds of begonias, gloxinias, and rechsteinerias. Baskets of pendulous tuberous begonias, fuchsias, ferns, and species African violets could hang from the ceiling.

   Start bringing house plants indoors by late August. Many of them can be left outside until early October, but in some areas frost may come by the middle of September. When plants have been placed directly in garden soil, it is usually better to make root cuttings of them instead of trying to save the old plants. If you want the old plants, dig them with as little root disturbance as possible. Repot in a container whose circumference measures one third to one half the height of the plant. Moisten thoroughly and place in a sheltered area, like a porch, for about a week. Before returning plants to the house, groom them carefully to remove damaged leaves and dried flowers. Scrub pots clean, then spray foliage, stems, and topsoil with an aerosol pesticide designed for house plants.