Post on 06-Jan-2016
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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