INORGANIC: This word really refers to the fact that a substance does not contain carbon. Over the years it has come to refer to a method of cultivation where inorganic fertilizers (‘artificials’) are used as a supplement to (or instead of) organic ones (the organic in this context intended to mean those derived from natural sources) and chemicals having a synthetic method of manufacture, instead of those of natural origin, are used to control pests and diseases. Exponents of ‘organic growing’ methods contend that ‘inorganics’ are unnatural or harmful in some way. However, plant foods in such substances are often obtained from minerals occurring naturally, and many organic compounds (that is, those containing carbon) can be produced synthetically. Most synthetic insecticides and fungicides contain carbon, and can be anything but harmless if used incorrectly, although technically ‘organic’. At best, many so-called ‘natural’ organic fertilizers are produced from slurry or poultry manure from intensively farmed animals, so the concept of ‘natural’ and ‘unnatural’ can become somewhat confused.
INSECTICIDE: A chemical that will kill insects and often other small garden pests such as mites as well, though the latter is more correctly known as an acaricide.
INTERNODE: A piece of stem between two leaf joints.