Rhs General Certificate Protected Cultivation

Front 1

List 6 environmental differences between the protected environment and outdoors

Back 1

Light
Temperature
(relative) humidity
Oxygen and Carbon dioxide
Pests and diseases
Easily modifiable environment

Front 2

Describe the greenhouse effect

Back 2

In a greenhouse, the glass allows short wavelength light through - the best suited to photosynthesis. Long wavelength light is reflected from the soil and plants - which includes infra red (heat). Glass does not allow long wavelength light out. The light has a direct effect on temperature.

Front 3

Name some house plants suited to reduced light

Back 3

From forest floor of subtropical and tropical forests:
Chlorophytum spp. (spider plants)
Monstera deliciosa (Cheese plant)
Schefflera spp. (Umbrella plants)

Front 4

What are the benefit of indoor cultivation with relation to temperature?

Back 4

In any enclosed situation the temperature can be more easily controlled than out of doors. It is generally more stable, with smaller and slower fluctuations in temperature

Front 5

What is the effect of a protected indoor environment on (relative) humidity?

Back 5

The increased temperature and lack of airflow causes a build up of humidity. A higher humidity environment is necessary for many subtropical and tropical (tender) plants.
(However central heating, gas and real fires dry the atmosphere)

Front 6

What are the effects of protected cultivation on Oxygen and Carbon dioxide?

Back 6

Enclosed spaces with limited airflow have reduced turnover of carbon dioxide and oxygen. Coupled with build up of humidity, this leads to a stuffy, relatively low oxygen atmosphere which is ideal for many fungi and bacteria.
Thus in a greenhouse or frame, good ventilation is essential and most have built in vents to allow good airflow.

Front 7

How are Pests and diseases effected in a protected cultivation environment?

Back 7

+ plants cultivated in pots or containers can be more easily quarantined if problem is caught early.
+ initial infestation difficult.
- once established, the environment often protects the pests and disease as much as the plants.
- high density of plants make it an ideal place.
- year round heating can mean that pests and diseases do not die back.

Front 8

Ways in which plant growth can be influenced in protected cultivation?

Back 8

Dormancy can be broken and flowering times induced at times that are not typical for the plant.
Plants in containers have free reign to grow without competition in the root environment.
Pests and disease can be treated on an individual basis.
Plants can be moved individually to areas best suited to their requirements throughout the season.