Transcript Greenhouse Management - Newburgh City School District

Hydroponic Agriculture
Controlled Environment Agriculture
Hydroponics
• Hydroponic farming is a method of growing plants
in water instead of soil.
• Why Hydroponics?
– Toxic Soil
– Nutrient Poor Soils
– Greater Yield
•
Scientific Applications
– Used to test how different nutrients affect a plant.
– Better control of nutrient feeding.
Germination
• When a seed starts to grow, we say it
germinates.
• The cotyledons store food for the baby plant
inside the seed.
• When the seed starts to germinate, the first thing
to come out is the main root.
• The skin starts to split and the tiny shoot
straightens, carrying the cotyledons with it.
• To grow, the seed's growing conditions usually
have to be damp, warm, and dark.
• A dry seed will stay dormant unless it soaks in
some water. Then it will start to germinate.
Plant Nutrition
• The method of nutrition common in plants, some bacteria,
and all algae is called ____________.
– photosynthesis
• These organisms are called ____________.
– autotrophs
• The raw materials ______________combine with sunlight
to produce glucose a.k.a simple sugar.
– carbon dioxide & water
• The glucose made is used as an ______ ______
– energy source
• Most ________in the air results from photosynthesis.
– oxygen
The Chemistry of Photosynthesis
• Photosynthetic Pigments are needed to “trap”
light energy.
– Chlorophyll a
– Beta-carotene (function not understood)
• Chemical Equation for Photosynthesis
– CO2 + H2O
light energy & chlorophyll a
C6H12O6 + H2O + O2
• Light energy absorbed by the Chlorophyll a is
converted to _______ __________.
– chemical energy (ATP).
• Photosynthesis in land plants occurs in the ____
– leaves.
Plant Physiology
• Roots
– Anchor the plant.
– Absorb raw materials needed for growth.
• Stem
– Supports the leaves.
– Contains the tissue used for transporting materials
throughout the plant.
– Xylem & phloem (like arteries & veins)
Physiology Continued
• Leaf
– Thin, flat which provides maximum surface area for
the absorption of light.
• Epidermis – protects the inner cells.
– Cuticle – waxy coating on some leaves.
• Palisade Cells – tall cells containing chloroplasts
which are filled with chlorophyll.
– Autotrophic nutrition occurs in the Palisade cells.
• Spongy Layer – Loosely arranged cells separated
by interconnected air spaces used for storing
gases.
• Stomate – micro openings on the leaf which allow
for the exchange of gases.
The Mineral Needs of Plants
• Plant growth requires more than sunlight, carbon
dioxide, chlorophyll, and water.
• Many plants require mineral substances derived
from the decomposition of rock.
• Hydroponics is a method of growing plants in
water enriched with mineral substances.
• Ten elements are essential to plants: calcium,
hydrogen, magnesium, oxygen, potassium,
carbon, iron, nitrogen, phosphorus, and sulfur.
• Other “trace” elements are needed like
manganese, zinc, & copper.
Movement of Minerals into Plants
• Plant cells absorb minerals in two major ways:
– Simple exchange through the cell membrane
(diffusion)
• Reversible
• Moves from high concentration to low
• Happens quickly
– Active transport - the movement of a substance
against its concentration.
• Irreversible
• Happens very slowly
Advantages of Hydroponic Gardening
1.
No weeds to pull means less competition.
2.
No soil borne disease.
3.
Grow more plants in a smaller space.
4.
Plants grow more rapidly and produce larger yields.
5.
Produce is higher in nutritional value than field grown crops.
6.
YOU CAN GARDEN ALL YEAR!
Maintaining Greenhouse Conditions
• Temperature
- Regulates germination, growth, flowering, fruiting,
longevity.
- 75/65 F generally will work for most species.
• Humidity
– 50-90% RH generally
– Plants, wet soils and floors provide humidity.
– Mostly worry about disease promotion.
– Vent or heat or both if condensation lingers on glass past
mid-morning.
– Pre-dawn venting
Continued
• Watering
– Quality--test clear water before growing your first plant.
Direct yourself to do it regularly for clear water and
fertilizer.
– Quantity—Do not over water plants by putting on too
much water at one time.
– Frequency--depends on weather, pot, soil, species, age.
– Application method--should be automated whenever
possible.