Refresh the room with plants, but beware...

Houseplants create a naturally fresh atmosphere, helping to boost one's state of mind.

india Updated: Feb 04, 2006 17:15 IST

The benefits of houseplants go beyond their ability to enhance the decor of a room. They also can create a naturally fresh atmosphere, helping to boost one's state of mind.

Houseplants also influence the overall air quality in a room by soaking up substances in the air and releasing moisture. However, simply placing plants on windowsills is not always the best way to optimise the air quality in a room.

Tests conducted by the US National Aeronautics and Space Administration (NASA) have shown that house plants can reduce concentrations of formaldehyde, benzol, xylol, trichlorethylene and other harmful gasses.

"Plants have a 'green liver'. They can take in harmful substances from the air and transform them into nontoxic substances," said Heinz-Joerg Haury, spokesman for Germany's GSF research centre for environment and health near Munich.

The detoxification is similar to the metabolic process that occurs in a human or animal liver.

Not all houseplants are suited to work as air filters for a room with particular fumes. If the problem is pungent formaldehyde from furniture, the ficus benjaminas (weeping fig) is alone at the top.

The plant, however, produces substances that can cause allergies among susceptible people. Other plants known to be good against formaldehyde are schefflera actinophylla (umbrella plant), epipremnum aureum (pothos or devil's ivy) and syngonium podophyllum (arrowhead vine).

Benzol, which is an ingredient in lacquers, is broken down by spathiphyllum floribundum (peace lily) or sansevieria trifasciata (snake plant or mother-in-law's tongue).

The mother-in-law's tongue's meaty leaves are easy to take care of. One can even skip watering it a few times.

Equally easy to care for is the dracaena draco (dragon tree), known to extract all toxins from the air.

It is, however, easy to overestimate the air filtering effects of houseplants.

"The efficiency of plants is reduced by their limited ability to absorb harmful substances," said one expert. "In order to achieve a noticeable effect, you would have to fill the room with plants."

Even when a room is meant to hold plants, there are several things plants need, including the correct positioning, sufficient light, fertilizer and moving air to optimize their filtering abilities.

Under normal conditions the filtering ability of plants is only marginal.

While their actual air filtering ability might be minimal, plants are well able to supply humidity to a room.

"It must be made clear to anyone who brings plants into a room that they will increase the humidity," said Thomas Gabrio of the state health office in Stuttgart.

Among the more thirsty plants are cyperus alternifolius (umbrella palm), chrysalidocarpus lutescens (golden fruited palm) and the sparmannia africana (African linden).

In winter when plants do not grow, they release virtually all the water that was poured over them into the air.

The additional moisture is one reason people put plants in their homes. But they often cause damage to the plant without knowing it.

New buildings can sometimes be too airtight, allowing for high humidity and the growth of mold. Moisture that goes into the air through cooking, showering or sweating escapes from the house inadequately and every plant can aggravate the problem.

Compounding the problem is the position of many plants in front of windows, which tends to limit regular airings of the room. It is especially important to air a room with many plants in it.

First Published: Feb 04, 2006 14:48 IST