Some people who have extensive indoor plant collections like to take holidays in the sun during our long, cold winters. Leaving houseplants unattended for any length of time can be risky; I have sometimes returned from a winter holiday to find a few dead plants and others a little worse for wear after a lengthy absence. There are steps that you can take, however, to help minimize the damage your indoor plants will suffer during your absence.
Just before you leave, water all plants thoroughly. Place pots on saucers and water plants enough that some accumulates in the saucers as a reserve, that will be taken up by the plants during the first week or so of your absence. Leaving any more water in the saucers might do more harm than good as the planting medium will be overly wet for too long.
Remove plants from locations where they dry out quickly, such as on window ledges where they get direct sun or receive heat from a nearby heat register. Ensure, however, that the plants will receive adequate light so that lack of light doesn’t cause them to deteriorate. Turn the thermostat down to a cooler setting; that way the plants will require less moisture.
Place plants (with accompanying saucers) that you fear will dry out most quickly on pebble trays to increase the moisture around their foliage. Better yet, place several plants together on one large pebble tray — grouping plants close together will also increase the humidity around the foliage, which will prevent the plants from drying out as quickly as they would if situated alone. (You don’t need to use pebbles in a so-called pebble tray; use anything that will keep the bottoms of the pots above the water in the tray.) Create a temporary greenhouse for a plant that likes lots of moisture by placing stakes in the pot and enclosing it inside a plastic bag — the stakes will keep the plastic from touching the foliage. Be sure such an arrangement is not in direct sun.
These precautions should keep most of your plants alive during an absence of no more than three weeks. For a longer time, have someone come in to water periodically, making sure to give clear instructions about how you want the watering done. The person will find the task easier if you group plants according to care required. For example, place cacti together on one table with a “no watering” sign — cacti can go for weeks during the winter without being watered. Large foliage plants in good-size pots will need to be watered less frequently than plants in smaller pots.
Provide a watering container such as a watering can or large measuring cup and leave instructions about how much water each plant should receive. This is particularly important for large plants, plants displayed in watertight jardinières, and hanging plants that may not have drainage holes in their containers.
If you have a plant that is irreplaceable — perhaps it is rare or has great sentimental value — ask a friend to keep the plant at his/her house during your absence to ensure its survival. With careful planning, you can have the best of both worlds — a sunny winter vacation and a healthy indoor garden.