The most essential thing to discover about any newly acquired plant is its water requirement. With a few exceptions it is better to let a plant nearly dry out before. Develop a regular pattern of inspection, twice a week or even daily if the room is warm. If in doubt, do not water.
When to water
How do you know when the plant needs water? The best way is probably a combination of looking and touching. Often it is possible to tell just by looking to see if the top of theis dry, but to make sure, touch the compost and push your finger down into it. If it feels heavy, do not water. After a time you will get to know the particular requirements of each of your plants. Plants in clay normally require more water than those in plastic. If you knock clay pots, they ring like a bell if dry, and give just a dull thud if wet. Watering is best done in the early morning or late afternoon. Try to avoid midday if possible, because if it is sunny, water splashed on the can cause scorching. Use water at room temperature if possible and avoid using cold water straight from the tap. Most plants prefer rain water, but of course, this is not always available.
How to water
Generally there are two basic methods of watering- from above or by plunging. The first is simply using a can with a longish spout and pouring water on top of the plant. This method can be used with the majority of plants. Be careful with plants like cyclamen and gloxinia and other plants with a central crown. If you wet this, the plant may rot. The plunging method is better for this type of plant. Immerse the plant in a bucket of water up to about 1 cm (2 in) below the top of the rim of the pot and hold it there for about a minute before removing. Allow the surplus water to drain off before replacing the plant in its normal. Some plants, like azaleas, hydrangeas and conifers, benefit from having the pot totally immersed. These should be left until air bubbles cease to rise from the compost. Again allow to drain and firm the compost gently down into the pot, before replacing.
Bromeliads are different in that nearly all varieties (except cryptanthus) like to have the cup or reservoir in the centre of the flower filled with water. This should be changed every three to four weeks.
Overhead spraying to increaseis another essential to keep plants healthy in the dry atmosphere of a house. Use a mister with a fine spray, so that large droplets do not fall on to the leaves or on the surrounding furniture. If possible, it should be done daily both in summer and winter, except on plants that are resting. Another way of increasing humidity is to place the plant on a saucer of water lined with small stones making sure the water does not touch the bottom of the pot. Alternatively, place the pot into a larger pot and pack the space between with wet peat or moss.