Calcicole: A plant that thrives on alkaline soil.
Calcifuge: A plant hates alkaline soils and will not grow in them.
Caliche: More commonly called hardpan, this is sometimes found in the south west of the USA. Lime (calcium carbonate) is deposited just below the soil surface either because of arid conditions or through the overuse of chemical fertilizers.
Calyx: The calyx is formed by the sepals of a flower and describes the green parts that cover the flower bud before it opens and then remains at the base of the flower afterward.
Capillary matting: Special matting to put on benches under pots and seed trays. The matting allows water to be drawn up into the soil.
Chlorophyll: The green pigment in plants that is instrumental in photosynthesis.
Cloche: A small protective structure made of glass or plastic on a metal or wooden framework. It is placed over delicate plants in the garden to protect them from frost or to warm the soil before planting out seedlings or sowing seeds.
Cold Frame: Similar to a cloche, this is usually a fixed structure alongside a greenhouse and mostly used to protect plants in pots or seed trays.
Companion Planting: Putting different plants in the same bed, usually to protect one of them from pests or diseases.
Compost: This is either a peat, coir or loam based potting medium or the organic product of a compost heap used for enriching and improving the structure of garden soil.
Compound: A structure like a leaf or flower made of one or more parts.
Coppicing: cutting back trees and shrubs close to the ground to encourage young, vigorous growth, particularly used as a woodland management technique and for the production of willow wands, etc, for fencing and basket weaving. Also, see pollarding.
Cordon: Usually a fruit tree restricted to one main stem by pruning.
Corm: A bulb like underground structure.
Corolla: The circle of petals, free or fused together, forming a flower.
Cotyledon: The first seed leaf to appear after germination of a seed.
Crocks: Pieces of broken earthenware pots put in the bottom of other pots to give free drainage and air circulation as well as the prevention of compost or soil blocking the drainage hole.
Crop Rotation: A 3 or 4 year cycle of moving vegetable crops into different beds to prevent the increase of plant specific pests and diseases.
Cross Fertilization: the fertilizing of a flower by the transfer of pollen from another flower.
Cross Pollination: The transfer of pollen from one flower to another, often by insects, to fertilize it.
Crown: Usually at ground level, this is the part of the plant where the roots meet the stems and from where new shoots grow. The crown also refers to the part of a tree above the bole.
Cultivar: Abbreviated from ‘cultivated variety’ and usually indicated by ‘cv’ next to the name of a plant.
Cutting: A piece of a plant cut and planted to produce a new plant.
Damping Off: The death of seedlings by either over watering or disease or a combination of both.
Dead Heading: Cutting off dead or dying flowers to encourage further blooms by preventing the setting of seeds.
Deciduous: Refers to plants that shed their leaves in autumn and then grow them again the following spring. See evergreen.
Dehiscence: Refers to fruits opening when ripe to release their seeds.
Dibber: A tool for making holes in the soil for individual seeds, bulbs or plants. It is often made from the top 6 to 9 ins of the handle of a broken garden fork or spade giving a useful handle and then the other end is rounded off.
Dieback: Tips and shoots dying on live plants. Often the dieback will progress up the stem or branch to the main stem so it is important to cut off the dead part.
Diocecious: A plant that has either male or female organs.
Division: Increasing plants by splitting the roots and top stems, eg irises.
Dormancy: The season or period when a plant stops growing, usually in winter.
Double Digging: A method of digging the soil by digging down two spits (the depth of two spade heads) then putting the soil from one row into the next row.
Double flower: See flower.
Double Potting: A system used in the USA for putting a smaller pot inside a larger one and then filling the space with peat which is kept moist to provide humidity.
Drill: A shallow straight furrow for sowing seeds.