Plant Production

Conditions for plant growth All plants need water, nutrients & oxygen to grow Normally plants can spread their roots to take these in

from the soil Potted plants have limited space for their roots to grow Potting compost helps to hold more water, air and

nutrients Rooting compost is good for drainage Various materials in potting composts Loam based compost – has good garden soil Loamless compost – has a lot of peat Rooting compost – to help cuttings to root - lots of sand (perlite)

Nutrients Absorbed by roots from

soil/compost Also known as minerals Some are major nutrients: - Nitrogen (N) – helps leaves

grow - Phosphorus (P) – helps roots

grow - Potassium (K) – helps

flowers/fruits grow Some are trace nutrients: - Iron, Magnesium

Fertiliser Contain extra supplies of nutrients Can be added to soil/compost Have different quantities (ratios) of each

mineral E.g. 4:2:1 4%Nitrogen, 2%Phosphorus,

1%Potassium Some are multi-purpose – same ratio of all Some are specific - e.g. fertiliser for leaf growth (more

Nitrogen) Can be applied as powder, liquid or

granules

Watering Plants need different amounts of

water There are many methods of watering: House Plants From above (with a watering can) From below (standing pot in a tray of

water) Garden Plants A hose (sometimes with a sprinkler

attached)

Automatic watering methods

Automatic Irrigation Water from above through

tubes and nozzles Capillary Matting Water from below through a

soaked mat Water Retentive Gel Within the compost – can hold

water for a long time

Environmental Conditions - Temperature

Each plant has an optimum temperature

Plants can be shielded from bad weather

- in a greenhouse - in a polythene tunnel A heater can set temperature - can be controlled by a

thermostat - a minimum/maximum

thermometer shows the range of temperatures over 24 hours

Humidity How much water vapour is in the air Plants lose water by evaporation - to cool the plants If air is humid (damp), less evaporation If air is dry, more evaporation Relative humidity allows air humidity to be

compared - 75% is high humidity / 20% is low humidity Warm temperatures allow higher humidities A hygrometer can measure humidity

Ventilation Greenhouses must be ventilated Avoids damp, stale air building up Autovents - attached to windows - have wax cylinders - as it gets hot, wax expands, vent

opens Extractor fans - controlled by thermostat - switched on if temperature gets too

hot Wind - increases evaporation from leaves - plants can be shielded from the wind

(windbreaks)

Plant Maintenance - cacti Have a fleshy stem – water storing

(succulent) Many stems have sharp spines Do not have leaves Desert cacti need direct sunlight &

well-drained soil Jungle cacti need a little shade & well

drained soil Both need warm summers & cool

winters Other succulent plants e.g. aloe have

leaves

Plant Maintenance -ctd Ferns - non-flowering - prefer humid, cool, dimly lit conditions Foliage plants - house plants grown for their leaf

shape/colour - prefer well lit, well watered

conditions, with feeds of fertiliser Flowering Plants Grown for their attractive flowers - perennial plants can re-grow flowers

every year

Maintaining Plants Pricking Out Sown seeds often too close together Seeds could compete for root space, water,

light Need to be re-planted elsewhere This is pricking out Happens when first set of leaves open out Potting On Moving a plant into a bigger pot Plant is moved when it becomes

pot-bound/root-bound Dead Heading Removing dead flower heads

Pests & Disease Pest – animal that damages a plant - E.g. aphid (greenfly) - suck out plant’s sugary sap - often attack shoots & flower buds Disease – caused by micro-

organism E.g. grey mould - grows on leaves, then spreads to

other parts - prefers damp, airless conditions

Controlling pests & disease Aphids - 1) chemical control - e.g. pesticides or insecticide - 2) biological control E.g. ladybirds - some don’t use chemicals – pick

them off or wash with soapy water Grey Mould - plants sprayed with a fungicide - burning all infected crops / better

ventilation

Protecting Cultivation Exposed plants can be

damaged by many things E.g. wind, rain, low temps,

frost Plants may need to be

protected: Glass Plastic Polytunnels Floating Fleece