250 likes | 520 Vues
Requirements for Plant Growth. Plants require certain environment for optimum growth In greenhouse one must maintain best environment for growth. Plant Media. Soil Sand Silt Clay Organic Matter. Water. Water 1. Gravitational Water (held by gravity) Drains away
E N D
Requirements for Plant Growth Plants require certain environment for optimum growth In greenhouse one must maintain best environment for growth
Plant Media • Soil • Sand • Silt • Clay • Organic Matter
Water • Water • 1. Gravitational Water (held by gravity) • Drains away • Soils with large pores lose water fastest
Water • 2. Capillary Water • Held against gravity in pores • Held in thin film around particles • Soil particles are electrically charged
Planting Media Mixes • Advantages to soil less media • 1. Mix is uniform • 2. Sterile • 3. Lighter in weight • 4. Good moisture retention and drainage
Planting Media Mixes • Disadvantages to soil less media • 1. Lightweight • 2. Minerals missing must be added • 3. Hard to transplant into soil
Planting Media Mixes • Content of mixes • Perlite: volcanic origin • Improves aeration • Small white pebbles
Media contents • Vermiculite: yellow expanded mineral • Increases moisture holding capacity
Media Contents • Sphagnum Moss: acid bog plants • Holds moisture, very light • Peat Moss: decomposed vegetation • Holds moisture
Media Contents • Tree Bark • Improves aeration
Plant Food • Water: most important • Plant weight = 90% water • 1% of water absorbed is used, rest is lost through leaves
Plant Food • Water: • Transpiration: Water lost through stems and leaves • Natural air conditioning
Plant Food • Major Nutrients • N, P, K • Numbers in fertilizer are those three in order so… • 10-15-20 = 10% N, 15% P, and 20% K
Plant Food • Nitrogen • Makes dark green color • Too much is a problem • Lowers disease resistance • Weakens stem • “leaching” is a problem
Plant Food • Phosphorus • Affects maturity • Cell division • Roots • Insufficient = purplish color on underside of leaves
Plant Food • Potassium • Affects Photosynthesis • Root System • Insufficient = also purplish color, much more rare than P
Soil Acidity • 0-14 • 0 = acidic • 14= basic • 7 neutral • Acid = add lime • Basic = add sulfur
Other Factors • Temperature 65-70 F • Light Short and Long Day Plants • Plant Diseases • Biggest scares to greenhouses • Insects our biggest problem • Gases