Glossary- Gardening Terms

quartz

A type of rock that is sometimes used as a non-organic mulch.

quick lime

Calcium oxide, which has been produced by burning a calcium carbonate such as limestone. It is highly volatile.

radicle

The first root sent out by a seed when germinating.

relative humidity

The amount of moisture in the air at any temperature, compared to how much moisture it could hold at that temperature.

resin

A substance that is secreted by trees, particularly coniferous trees. This substance can be sticky but normally hardens. It is not tree sap, but rather a protective reaction to damage or insects.

rhizome

A fleshy underground stem of a plant that is commonly mistaken for a root. Roots and shoots grow off the rhizome.

ring culture

A method of growing tomatoes in bottomless pots or “rings” placed over gravel pits.

river rock

A natural stone, normally rounded, that is used as decoration in gardens.

rock mulch

A ground covering that is made up of rocks.

root ball

The entire root system of a plant.

root bound

A disorder of the root system that occurs when a plants is allowed to grow too long in a pot that is too small for it. The roots wrap around in on themselves and become tangled.

root pruning

Cutting back the root system. It is typically done to either combat a disease, such as root rot, or to stunt the plant, such as with bonsais.

rooting hormone

A chemical, either man-made or natural, that is applied to a cutting in order to encourage root growth.

runner

A stem that grows off a plant and produces a new plant at its tip. It is a common way for ground covers to spread.