Interior Gardening

• A plastic-mesh bag filled with marbles set inside a container holds flower arrangements beautifully. Set the bag in the container and cover it with water, and the marbles will grip flower stems firmly without injuring them.

• To prevent slugs and similar pests from entering the drainage holes of potted plants that have been set into the ground during summer, slip the pot into the toe of an old nylon stocking. This allows water to get through, but keeps out pests.

• Hanging baskets exposed to sun should be checked daily and watered if needed. Also, outdoor hanging containers should be sheltered from high winds.

• When you go on a short vacation, one thorough, deep watering just before leaving will usually be sufficient. The same is true for houseplants. Many times, a thoughtful neighbor can literally kill your plants with kindness by overwatering them.

• If you keep your houseplants indoors all summer, keep them out of the draft of the air conditioner. Plants react to an air conditioner's cool air in various ways. Some drop their leaves, others don't bloom well, and some fail to bloom all together.

• Peat pellets that swell up to form both pot and growing medium for seedlings can be used for air layering. After the pot has soaked and expanded to full size, slit it vertically on one side so it will fit over the plant's stem. Next, wound the plant stem by cutting two fine rings around the stem a half inch apart in the bark or skin with a sharp knife. Peel off the area between the cuts, and slip the pellet over the stem. Cover the wound with a plastic bag tied at both ends to conserve moisture. When roots appear in the bag, remove the plastic, sever the new plant and pot it up.

• Houseplants grown in clay pots may be sunk in a partially shaded flower bed or border for the summer. If your plants are grown in glazed or plastic containers, remove the pot before planting them in a flower bed.

• According to studies conducted by NASA, plants can function as biological, air-purification systems. Spider plants (Chlorophytum spp.) are highly efficient in absorbing toxic substances. In tests, these plants absorbed toxins, such as formaldehyde, carbon monoxide and nitrogen dioxide, known to be present in homes and offices. To purify the air in an average-size, well-insulated home, 8 to 15 mature spider plants would be required. Other plants that also lowered pollutant levels, but to a lesser degree, were Chinese evergreen (Aglaonema spp.), golden pothos (Epipremnum aureum) and peace lily (Spathiphyllum spp.).

• House plants can be kept in good condition for several weeks while one is on vacation by using clear, plastic bags as miniature greenhouses. Simply soak the soil thoroughly, allow to drain, then place the potted plant into a plastic bag and tie the opening tightly. Two or more sticks in the soil will support the plastic tent and prevent it from resting on the plants. Plants, such as African violets, that are apt to develop mildew should have a few air holes cut for air circulation.

• To avoid soaking the soil when washing off the leaves of potted plants, use a shield. Slit an aluminum foil pie plate from the rim to the center. Turn under the cut edges and slip it around the plant stem so it covers the soil and allows the water to run off.