Humidity
Most houseplants are tropical plants and come from places where the humidity (the amount of moisture in the air) is as high as 70,80 or even 90 percent.The amount of moisture in the air influences the health and growth of plants Deserts cacti in hot regions have thick outer layers that reduce the amount of moisture they give off.Most plants however ,need a humid atmosphere to prevent their leaves and stem becoming dry. Spraying them regularly with water from a spray bottle or sprinkling water on the leaves;or setting them on a tray or a plastic saucer filled with pebbles and water, will increase the humidity around the plants together helps raise the humidity, too , because when they transpire, or breathe, they give off humidity to one another!

Don't Spray Water
1) When the sun is shining.Water globules act as lenses,intensifying the sun's rays and burning leaves . 2) During evenings, especially in autumn & winter .Instead, mist-spray in the morning, so that the moisture has a chance to dry before the onset of night.

Grouping Of Plants for Humid Atmosphere
Placing plants in groups creates humid micro-climates (a small area with high humidity)around them. Moisture given off from the surfaces of leaves is trapped. When a plant is diaplayed on its own, moisture soon disperses.

Keeping The Atmosphere Humid
Regularly mist-spray smooth-surfaced leaves in summer.However, take care not to spray water on flowers, as they then soon decay.Place a piece of card in front of the flowers.Afew plants suchas philodendrons and the Swiss Cheese PlantThese must be mist-sprayed in summer to prevent them from becoming dry and hard.

Excessive Humidity
1) Soft leaves soon decay, especially if hairy. Moisture becomes trapped around the hair on the leaves.
2) Leaves that are close to the stems create traps for water.
3) Flower petals,especially when tightly packed together, become covered wirh a furry mould.
4) Plants with masses of soft leaves closely packed together become infested with decay.

Dry Atmosphere (Less Humidity)
1) Tips of leaves shrivelled,curled and brown.The whole plant wilts if the temperature is very high,with leaves eventually falling off.
2) Flowers fade and discolour, with flower buds wilting and eventually falling off.
3) Surfaces of leaves become dull.
4) Tips of shoots wilt,then shrivel.