1. Environmental Requirements for Good Plant Growth
Unit 4
Environmental Requirements for Good Plant Growth

2. The Greatest Influence
The greatest influence on plants
Water
Nutrition—16 elements from soil or fertilizers
Medium—soil or soil substitute
Temperature—growth influenced by heat
(continued)

3. The Greatest Influence
The greatest influence on plants
Light—intensity of light affects photosynthesis
Humidity—moisture level in the air
Insects and disease—reduce production

4. Importance of Water
Most of the water is contained in the cells (vacuoles)
Necessary for photosynthesis to occur

5. Importance of Water
Helps to transport nutrients and produces food throughout the plant. (Photosynthesis)
Nutrients from the soil must be in a water in order for the plant to absorb them.
(continued)

6. Importance of Water
Water vapor evaporating from leaves cools the plant (Transpiration)

7. Inadequate Water Can stress plants
Makes plants more susceptible to disease and pest.
Slows the process of photosynthesis

8. Nutrition
Plants require at least 16 elements from the soil or from fertilizers
Nutrition is important to plant health and good growth
In loam soils (sand, silt, clay), enough minor elements are available for satisfactory plant growth
(continued)

9. Nutrition
In soilless mixes (vermiculite, perlite), minor elements may be deficient
The major elements nitrogen, phosphorus, and potassium are needed most often (N-P-K)(Fertilizers)

10. Temperature
Plant growth is greatly influenced by heat
(continued)

11. Temperature
Plant growth increases as temperature increases up to 86°F (31°C) for most plants
Cooling plants below their best growing temperature causes reduced growth.

12. Soil
Chemical use—causes loss of native soil fungi and beneficial microorganisms
Made up of sand, silt, clay, organic matter, living organisms
Consists of three layers
Topsoil, subsoil and soil bedrock

13. Three Types of Soil Sandy Clay Loamy
Silt and clay make up less than 20%
Clay
At least 30% clay
Loamy
Best soil is equal parts of sand, silt, and clay

14. Soil Improvement Drainage and aeration—add organic matter
Add lime and gypsum (calcium sulfate)
Raise plant beds
(continued)

15. Soil Improvement Moisture retention—add organic matter Animal manures
Mulches
Peat moss
Fertilizers

16. Soil Deficiencies Nutritional Deficiencies Pests and Diseases
Nitrogen—yellow or pale green leaves
Phosphorous—purple color underside of the leaves
Pests and Diseases
Examples— insects, root rot, fungus

17. Content of Soilless Mixes
Perlite
Sphagnum moss
Peat moss
Vermiculite
Limestone
Tree bark
(continued)

18. Content of Soilless Mixes
Slow-release fertilizers

19. Plant Food and Fertilizers
Nitrogen:
has the most noticeable effects on plants (green appearance)
(continued)

20. Plant Food and Fertilizers
Phosphorous—encourages plant cell division, increases resistance to disease and encourages strong root growth
Potassium

21. Soil Acidity (pH) To lower pH in alkali soils
Add sulfur, iron sulfate, or aluminum sulfate
(continued)

22. Soil Acidity (pH) Lime: raises pH levels activates soil organisms
encourages the release of food

23. Plant Hardiness Zones
12 zones—based on the average number of days the daily high temperature reaches or exceeds 86°F
Use zones as a guide of plant adaptability
Factors used to determine plant choice include rainfall, wind, sun, humidity, snow cover

25. Wrap up For successful plant growth:
It is extremely important to consider the plant environment both underground and aboveground
Soil conditions and soilless mixes must match plant needs
(continued)

26. Wrap up
Plant medium must be evaluated in terms of soil, pH, drainage, and fertility
Soilless mixes specially formulated for most plants grown in containers are now available
There is little, if any, need to mix your own anymore
(continued)

27. Wrap up Important aboveground factors
Temperature, sun, and wind exposure
Select only plants adapted to the environment they will be placed in