The key to maintaining healthy plants while you're away is to make sure they have plenty of water. Houseplants should be repotted in containers that retain water. Terra cotta, wood and cement all allow water to evaporate quickly while containers made of plastic, fiberglass, metal or glazed ceramic retain water.
Also, avoid potting plants in dark pots that absorb heat and tend to dry out the soil faster. A light-colored or white pot will reflect heat and keep plants cooler.
Several products can help plants retain moisture over long periods of time.
- Polymers, the small white granules in potting soil, can cut watering frequency in half. Using a pencil, poke several 2-inch deep holes in the soil (make sure the holes are deep enough to reach the roots but not too close to the center stems of the plant). Fill the holes with polymers, cover with soil, and water the plant thoroughly. Polymers can be purchased in garden supply stores by the pound. A one pound bag costs about $15 but lasts several seasons.
- Terra cotta cones can help plants get plenty of water. These nifty devices are cylinders made of terra cotta with a cork ring on top. Push the top of the cone into the mouth of a plastic soda bottle filled with water. Invert the cone and the bottle and place the cone into the soil of your plant. The terra cotta will absorb the water from the bottle and release it slowly into the soil. Terra cotta cones cost $12.50 for three and can be found at Gardener's Supply Company, www.gardeners.com.
- Commercial plant watering wicks can keep plants moist. They look like shoelaces with a plastic knob at one end. Soak the wick in water until saturated. Water the plant thoroughly, place the plastic end of the wick into the soil of the plant and place the other end in a 16 to 32 ounce container filled with clean water, making sure to keep the container at a lower level than the water. The water will slowly diffuse into the soil and keep the plant moist for a week or two. The wicks are available at garden supply stores.
For outdoor containers that need regular watering, dig a trench in a shady area of your garden. It need only be as deep as the pots are high. Place the plants in the trench, again keeping the smaller plants near the center, and fill the trench in with soil. Cover the soil with mulch and water thoroughly.
For outdoor gardens, buy a sprinkler timer. The timers attach to an outdoor faucet and have a connection for a standard hose and sprinkler. Prices range from $40 to $100. The high-end models can be set to turn on up to 6 times a day.
It is best to set the timer to water plants early in the morning before the sun is high in the sky and evaporates the water. It is also a good idea to water at the root, not over the leaves. Garden centers now sell special hoses that lie beneath the leaves of plants near the roots and allow water to slowly seep out from small holes.
If you plan to be away from home for more than two weeks, it's still a good idea to ask a friend or neighbor come by to water your plants for you.