Common sense tells us that plants need light to survive and grow. Architects who have envisioned living greenery throughout their build­ing interiors have been disappointed when all the leaves dropped sev­eral days after installation, returning slowly or not at all. These are the questions that need answers.

• How much light do interior plantings need?

• What kind of light do they need?

• What sources of light exist indoors?

One final question must be answered if everyone connected with the plantscape is to have realistic expectations: How long will plants live indoors? The answer depends on the plant, of course, but the general answer is that in interior design, as elsewhere, nothing lasts forever. Carpets wear thin; furniture must be replaced; walls require fresh paint. Plants must be regarded as perishable furnishings as well. If installed correctly into a properly designed setting and maintained properly, they will serve satisfactorily for a time period that will unquestionably justify their cost. Then they will require replacement.