Gardening Glossary

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N

The chemical symbol for nitrogen.

nastic movement

A movement of a plant part (such as a leaf) not caused by an external stimulus.

native plant

A plant indigenous to a specific habitat or location.

natural selection

The action of the environment on organisms such that those better able to survive environmental stress are more likely to survive and reproduce.

naturalize

(1) To design a garden with the aim of creating a natural scene. Planting generally is done randomly, and space is left for plants to spread at will. (2) The process whereby plants spread and fill in naturally.

necrosis

Tissue death.

nectar

A sugary fluid secreted by some flowers.

nectar guide

A contrasting color pattern on a flower that guides pollinators to the nectar.

nectary

A gland secreting nectar.

nematocide

A material that kills or protects against nematodes.

nematode

A microscopic roundworm, usually living in the soil. May feed on plant roots and can be disease pathogens or vectors. Others are beneficial parasites of insect pests.

nitrate (NO₃^-)

A plant-available form of nitrogen contained in many fertilizers and generated in the soil by the breakdown of organic matter. Excess nitrate in soil can leach into groundwater. See nitrogen cycle.

nitrifier

A microbe that converts ammonium to nitrate.

nitrogen (N)

A primary plant nutrient, especially important for foliage and stem growth.

nitrogen cycle

The sequence of biochemical changes undergone by nitrogen as it moves from living organisms, to decomposing organic matter, to inorganic forms, and back to living organisms.

nitrogen fixation

The conversion of atmospheric nitrogen into plant-available forms by Rhizobia bacteria living on the roots of legumes.

node

The point on a plant where a branch, bud, or leaf develops. On younger branches, it usually is marked by a slight swelling. The space on the stem between nodes is called an internode.

nonpoint source

A relatively small, nonspecific source of pollutants that, when added to other sources, may pose a significant threat to the environment. See point source.

nonselective pesticide

A pesticide that kills most plants or animals.

N-P-K

The acronym for the three primary nutrients contained in manure, compost, and fertilizers. The N stands for nitrogen, the P stands for phosphorus, and the K stands for potassium. On a fertilizer label, the N-P-K numbers refer to the percentage of the primary nutrients (by weight) in the fertilizer. For example, a 5-10-5 fertilizer contains 5% nitrogen, 10% phosphorous, and 5% potassium.

nucleus

The organelle (structure) within most living cells that contains the chromosomes which controls various cellular processes, including division into new cells. Bacteria and viruses do not have a nucleus; their chromosomes are distributed throughout the entire organism.

nutrient

Any substance, especially in the soil, that is essential for and promotes plant growth. See macronutrient, micronutrient.

nymph

The immature stage of an insect that undergoes simple metamorphosis. Usually similar in form to the adult.