When it comes to house-plant care, the three main things you need to consider are light, humidity and temperature. Get those right, and your plants will thrive. Get them wrong, and they will wither away. Here are some tips for making sure your 'green pets' stay healthy and happy in your home.
Providing the right amount of light to indoor plants can be tricky. Plants fall into three groups as far is light is concerned. Some need full sunlight, some are happy with partial shade and a few prefer to sit in a shady spot. Shade-tolerant plants like peace lilies, begonias and herringbone plants are the easiest to deal with, as you can find them a home away from a window, and they will be happy.
Plants that tolerate only some degree of shade can be trickier to deal with. Calatheas in particular will let you know if they are getting too much sun, because their leaves curl up and become pale, the variegations appearing bleached out. Too little light will also produce less variegated leaves, but these will be darker as the plant produces more chlorophyll to make the most of the light it is getting.
Some plants like bright, indirect light, so placing them in a position a few feet away from a window where the light is diffused, or near a window with a muslin or voile curtain, will allow them to receive the light they need without being scorched. These plants will thrive better in east- or west-facing windows where they will get two to five hours of sun, but not the full heat of the midday sun.
With plants that like full sun, such as yucca trees, mother-in-law's-tongue and aloe vera, you have to play crafty. If you have a conservatory or sun room, that's the best place for them. Otherwise, they need a spot in a south-facing window where they will receive five or more hours of sun and can bask in midday heat. The challenge is to get them close enough to the window to receive its light without having their leaves touching the glass, as the window heating up will scorch them and the cold from it at night will also damage them. With a small plant, that's easily done. But as they grow, you may need to place a table or shelf in front of the window for them to sit on.
Few plants like dry air. Most will not tolerate less than 50 percent humidity, and their leaves will turn brown and brittle or suffer from leaf drop, with flowers dying in bud. If you're unsure about the humidity levels in your home, a cheap barometer is all you need. If you have a dry home due to central heating, consider a humidifier to raise the humidity to more comfortable levels for you as well as your plants.
If you only need to raise the humidity around your plants, you can do this by misting them with a spray bottle two or three times a day or by placing them in gravel-lined trays with water in the bottom. As the water evaporates from the tray, it provides the plant with its own micro environment. Or group plants together so that as water evaporates from the leaves of one, it increases the humidity of the air for all.
If you keep your home between 65 and 72 degrees during the day and overnight temperatures don't drop lower than 15 degrees or so, you should have no problem with house plants temperature-wise. Most will even cope with summer temperatures up to 90 degrees, provided the humidity levels don't drop too much. These are, after all, plants that evolved to grow outdoors where conditions can be extreme even in the mildest climates.
However placing a plant in a draft, near a fan or air-conditioning vent, exposes them to unnatural shifts from hot to cold that few plants cope with in their natural habitat.