BGCSE Horticulture 1257 key terms

The process by which green plants use light energy to combine carbon dioxide and water into sugars, releasing oxygen. It supplies the carbohydrates that fuel growth, flowering and fruit production.

The loss of water vapour from plant leaves through small openings called stomata. It pulls water and dissolved minerals upward from the roots and cools the leaf surface.

The breakdown of sugars inside living plant cells to release energy for growth and maintenance, using oxygen and giving off carbon dioxide and water. It continues day and night.

Tiny adjustable pores, mostly on leaf undersides, that let carbon dioxide in and water vapour and oxygen out. Guard cells open and close them in response to light and water stress.

A piece of stem, leaf or root removed from a parent plant and placed in a suitable medium so it forms roots and becomes a new independent plant.

Joining a shoot piece (scion) onto a rooted stem (rootstock) so the two grow together as one plant. Used to combine a good fruiting top with a hardy or disease-resistant base.

A synthetic or natural growth substance, usually containing auxin, applied to the cut end of a cutting to encourage faster and more uniform root formation.

The relative proportions of sand, silt and clay particles in a soil. Texture strongly affects drainage, water holding, aeration and how easily the soil can be worked.

The way soil particles clump together into crumbs and pores. Good structure allows air, water and roots to move freely and resists compaction and erosion.

A balanced soil containing roughly equal parts sand, silt and clay plus organic matter. It is generally the most desirable garden soil because it drains well yet holds moisture and nutrients.

A scale from 0 to 14 measuring how acidic or alkaline a soil or solution is, with 7 neutral. Soil pH controls how readily plant roots can take up nutrient elements.

Ground limestone or similar material spread on soil to raise pH and reduce acidity. It also supplies calcium and improves conditions for many vegetables and lawn grasses.

A material added to soil or applied to leaves to supply essential plant nutrients. Fertilisers may be organic, such as manure, or manufactured and are described by their nitrogen, phosphorus and potassium content.

Decayed organic matter produced by stacking plant wastes and allowing microbes to break them down. It improves soil structure, water holding and nutrient supply when dug in or used as mulch.

A layer of material such as straw, bark, compost or plastic spread over the soil surface. It conserves moisture, suppresses weeds and moderates soil temperature.

A combined approach to pest control that uses monitoring, resistant varieties, cultivation, biological agents and careful pesticide use, applying chemicals only when pests exceed acceptable levels.

Using living organisms such as predators, parasites or disease organisms to reduce pest populations. Examples include ladybirds feeding on aphids and parasitic wasps attacking caterpillars.

Any substance formulated to kill or control pests, including insects, fungi, weeds or mites. Correct label rates, protective clothing and harvest intervals must always be observed.

A pesticide designed to kill unwanted plants. Selective types harm only certain weeds while non-selective types kill most vegetation, so application timing and method matter greatly.

An abnormal condition caused by pathogens such as fungi, bacteria or viruses, or by environmental stress. Symptoms include spots, wilts, rots, mosaics and stunted growth.

Gradually accustoming seedlings or young plants raised indoors or in a greenhouse to outdoor conditions over one to two weeks before planting out, reducing shock and losses.

Moving a seedling or established plant from one growing position to another with minimal root disturbance. Careful watering and shading after the move improve survival.

Deliberately removing branches, shoots or roots to shape a plant, control size, improve air movement or encourage flowering and fruiting. Cuts should be clean and correctly placed.

Removing faded flowers before they set seed. This tidies the plant and often encourages further flowering because the plant's energy is redirected into new blooms.

Planning the arrangement of plants, paths, lawns and structures to create a functional, attractive and manageable outdoor space suited to the site and the users' needs.

Growing different crop families on the same ground in a planned sequence over several seasons. It helps prevent build-up of soil-borne pests and diseases and balances nutrient use.

Growing certain plants close together because they are believed to repel pests, attract beneficial insects or otherwise assist each other's growth.

The transfer of pollen from the male part of a flower to the female part, allowing seed and fruit to form. Wind, insects or hand brushing may carry the pollen.

Growing crops under structures such as greenhouses, shade houses, tunnels or screens that modify temperature, light, wind or pests to extend and safeguard production.

All operations after harvesting, including cooling, cleaning, grading, packing, storage and transport, that maintain produce quality and reduce losses before sale.

Holding harvested produce at low, controlled temperatures to slow ripening, respiration and decay. Correct temperature and humidity differ between crops.

Sorting produce into uniform classes by size, shape, colour and freedom from defects so that buyers receive consistent quality and prices can be set fairly.

The total money spent on growing a crop, covering seed, fertiliser, labour, fuel, water and equipment. Comparing it with expected sales shows whether the enterprise is profitable.

The value of sales from an enterprise minus its variable costs. It allows growers to compare the profitability of different crops before shared fixed costs are considered.

Producing plants and crops in ways that conserve soil, water and biodiversity, reduce waste and pollution, and remain profitable and useful for future generations.

Clothing and gear such as gloves, boots, goggles and respirators worn to protect the worker from pesticides, sharp tools, dust and other hazards during horticultural tasks.

A document supplied with a hazardous product that lists its hazards, safe handling, first aid and disposal advice. It should be read before using the product.

The proportion of seeds in a sample that are alive and capable of germinating under suitable conditions. It is tested by counting normal seedlings produced from a known number sown.

The resumption of growth by a seed, beginning with water uptake and ending with the emergence of the young root and shoot. It requires moisture, warmth and, for most species, oxygen.

In a horticultural investigation, the treatment kept unchanged so results can be compared fairly. All other factors should be held constant to show the effect of the variable tested.