When each plant is watered and fed at its appointed time, just check over theor the foliage to make quite sure all is well. Look for distorted or discoloured , for portions of the plant that appear to droop, look for falling and inspect the plant quickly to make sure that no insect pests are visible, looking particularly at the tender growing shoots. An examination of this sort need take only a few seconds, but it can discover, identify, check and correct many possible troubles that might occur far more seriously in the future.
But although you go over all your plants at one time this does not mean that all must be treated alike. You may find that one plant is actually flagging for want of water while another has a soil surface moist both in appearance and to the touch and so needs no water at all. One plant may have shed aor two in the normal process of growing while another may have shed a leaf or two as an indication that it is sickening. A little observation and experience will soon tell you which is which.
Some plants tend to collect dust on their leaves, depending on the size of the leaves and the amount of dust in the atmosphere. Obviously a home in a busy city or an industrial centre is likely to have more dust than one out in the cleaner air of the countryside. This dust can clog the breathing pores, the stomata, in the leaves and cause the plant to sicken. So both for the health of the plant and its appearance it is well to give most plants an occasional clean.
Where there are large leaves—such as those of an india rubber plant or a Swiss cheese plant—this is a comparatively simple matter, for the leaves are few in number and quite easily swabbed down. Use a tissue or a soft sponge and tepid rain water. Never use olive oil, milk or anything else that is likely to clog the pores even more or which will collect even more dust. If you like the leaves to shine, you can use one of the several AEROSOL sprays on the market after having cleaned them with rain water. Do bear in mind that some dust, particularly that deposited in cities and industrial areas, can be sharp and gritty. If rubbed off the leaves too vigorously this abrasive dust can do real harm. Instead try to clean the leaves gently, using plenty of water. I suggest rain water mainly because it is soft and it does not leave any of the lime or chlorine deposits sometimes seen after using tap water.