Transcript For growth to occur, photosynthesis must be greater than respiration

Climate
Climate is the year round weather
in an area
• Climactic variables
– First and last frost dates
– Average winter and summer temperatures
– Precipitation and when it occurs
– Snow depth
– Wind and storm patterns
– Lake effect
– Hours of sun vs. cloud cover
Macroclimate
• describes the climate over a large area
such as the north central US
– Largely determined by latitude
• Temperature
– Department of Agriculture Zone Map
• Growing zones described by winter temps and
growing season
• Heat Zone Map
Hardiness Zones
Zone changes in 16 years
• Excessively high temps can cause the
plant to stop growing. This varies
between species but generally occurs by
96F.
• 539cal/gm to turn water to water vapor.
Leaves have evaporative cooling
(evapotranspiration)
• In Duluth, we have Lake Superior!
Microclimate
• describes the climate in your yard or
garden
• Slope
• Buildings
HOW TO PREVENT COLD
DAMAGE
• Hardening off: (spring) get greenhouse grown
plants used to the outdoor temps gradually.
• 80Cal/gm are given up to change 1 gm water to
ice , so you can use water as frost protection
• covering
• Season extenders (fall), plant covers , mulches,
leaves, leaf bags, straw etc
• Put plants in the ground at the right time ( soil
temp) cool season vs. warm season plants
Five environmental factors
essential for plant growth
•
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Light
temperature
Water
Air
nutrients
Light quantity
• Quantity
– refers to the intensity
or concentration of
sunlight
– Measured in foot
candle, lux, lumen,
watts
– “full sun” 8 hours of
unshaded sunlight
during the growing
season
Light Quality
• Wavelength that hits
the plant surface
• Red and blue light
have the greatest
effect on plant growth
Light Duration
• The amount of time the plant is exposed to
light during a day, plants are classified in 3
categories by their flowering response
– Short day plants flower when the days are shorter
than 12 hours ( long nights)– ( fall asters)
– Long day plants flower when the days are more than
12 hours ( short nights)
– Day-neutral flower in long day or short ( ever bearing
strawberries)
Temperature
• Horticultural plants can be defined as warm-season or
cool-season crops
• Temperature interacts with light duration.
• For growth to occur, photosynthesis must be greater
than respiration
Water
Plants must have water
available for growth to happen
Growth can happen
growth delayed
permanent wilt point
Air
• Plants use CO2 in photosynthesis
• Plants use O2 in cellular respiration
• Air movement can increase or decrease
transpiration and can shape plants
• Air quality is important – plant leaves can
be damaged by air polution
Nutrients
• 16 essential nutrients are supplied through
air and soil.