1. Greenhouse Growing Media and Plant Fertilization
Mr. Wilson
Greenhouse
Uintah High School

2. Unit Objectives
Examine the components and properties of growing media.
Describe the components of growing media.
Describe the functions of growing media.
Determine desirable properties of growing media.
Evaluate the advantages and disadvantages of soilless media.
Investigate chemical characteristics of growing media.
Interpret pH test results of a growing media sample.

3. Additional Objectives
Supply nutrients to greenhouse crops.
Explain plant nutrition.
Describe pH and how it is modified.
Describe the components of a fertilizer.
Explain the methods of applying fertilizers to horticulture crops.
Demonstrate proper techniques for sampling growing media.
Test and determine pH level of various growing media.

4. TERMS Aeration – the presence of air
Growing medium – material used for plant growth
Hydroponics – growing plants w/o “soil”
Leach – to remove by percolation
Pore spaces – voids for water or air holding
Soil – outer layer of the earth suitable for plants
Soilless medium – sterile product/s used for plants

5. What is growing media?
The material that your plants grow in is called the “growing medium.
Characteristics:
Soil-less mix – usually doesn't contain soil
Used to grow greenhouse and nursery plants
Usually is pasteurized
Usually purchased or made

6. Functions of Growing Media
Growing medium has three main functions
1) Supply roots with nutrients, air, and water.
2) Allow for maximum root growth.
3) Physically support the plant. Anchor roots!
Roots grow in the spaces between individual particles of soil. 
Air and water also travel through these pore spaces. 
Water is the medium that carries nutrients that plants need to fuel their growth, and air is needed for root growth and the health of soil microorganisms that help supply plants with nutrients.

7. Advantages of Soil less Mixes
sterile
lightweight
good moisture retention and drainage
free of weed seeds
Designed for the plant type!

8. Disadvantages of Soil less Mixes
light weight - pots tip in strong wind
minor elements are missing
transplants may not adjust well to new media

9. Which Makes the Best Growing Medium?
Sand
Peat Moss
Field Soil
Vermiculite
Pearlite
Water
Gravel
Find out from the class what they feel is the best medium.
Question where “soil” is used for floriculture?
Ask how they have purchased plants and what the medium was?
Lead a discussion on what each sample contains that allows it to be used as a growing media.

10. What are the types of growing media used in greenhouse production?
Is “soil” used?
Soil – the earth’s outer crust is full of life!
Bacteria
Fungi
Invertebrates
Yes – we use field grown plants for some production. Outdoor production has problems of its own. Bacteria – fungi - …. Cut flower production can occur outside of a greenhouse. Some greenhouse production is in field soil.

11. What are the negatives of using “SOIL” for containers?
Unknown history of:
Pesticides pH
Fertility level
High shrink / swell
Soil shrinks as it dries – forming cracks
Higher disease probability
Container medium must be sterile!! Container medium must be spongy!
Can field soil be sterilized? Fumigants and steam can kill all life in the soil.

12. So what media should you use?
Sand? Dries to quickly.
Peat moss? Dries to slowly.
Choir? Hard to get wetted.
Water? To little air.
Pearlite? To much air.
Vermiculite? Pricey.
Potting soil mixes? Just right.
Many materials can be used – each has its own pitfalls
Choir – coconut fibers that are hollow
All material can be reduced in size and thereby its properties for a media
In general, a combo of materials is used.

13. What effect does growing media have on plant growth?
Supplying Nutrients
Some media cannot hold essential elements for plants. Nutrients are leached out to rapidly.
Stressed plants are prone to disease and insect damage – increasing loss.
Reduced growth = lower returns
Choosing the right growing media for floriculture crops is very important. The media can affect the amount of nutrients that are available for the plants, the presence of water, and the ease of growth plants.

14. What effect does growing media have on plant growth?
Supplying Air
As air is reduced, plant stress increases.
Roots need oxygen and water – both in moderation.
Increasing stress increases pest susceptibility and profit loss
The ability of the growing media to drain water is very important for plant growth. Plant
roots need oxygen to function properly and if the growing media is saturated with water,
the plant roots will die due to lack of oxygen. The roots may also rot. Excess water in the
growing media can also lead to insect problems.

15. What effect does growing media have on plant growth?
Uniformity
Large scale production demands that all plants perform equally.
This is only possible if all plants get equal inputs from a uniform media.
In the production of floriculture crops, it is important to use a growing medium that is
uniform. With a uniform mix, watering, fertilizing, and transplanting schedules can be
developed in order to insure even growth of the crop.

16. Content of commercial mixes
Soilless mixes contain various combinations of the following materials.

17. Perlite
improves aeration
of volcanic origin

18. Spahgnum Moss Dehydrated remains of acid bog plants
Used to cover seeds because it is lightweight, controls disease, and holds moisture.

19. Peat Moss Partially decomposed underwater vegetation.
Holds moisture well
Low in nutrients

20. Vermiculite
Exploded Mica
Improves aeration
Holds moisture very well

21. Limestone
Raises pH
You would not want to use this in our area’s natural soils.

22. Plant nutrients and fertilizers Plants do not eat! Not Food!
Water
Elements

23. Water Water is the most important plant nutrient
Makes up 90% of the plants weight
Water transports the other elements around the plant

24. Elements divided into two groups, macro and micro
Major elements (macro)
Nitrogen – N
Phosphorus – P
Potassium - K

25. minor elements (micro)
Calcium - Ca
Magnesium - mg
Sulfur - S
Iron - Fe

26. minor elements (micro)
Manganese - Mn
Boron - B
Copper - Cu
Zinc - Zn

27. Plant requirements large amounts of major elements
relatively small amounts of minor elements

28. A way to remember the Nutrients required for plant growth.
C.B. HOPKiNS CaFe Mighty good
Closed Monday Morning See You Zen!
Other elements for plants? Not essential but help plant growth:Se, Ni, Co, Na??

29. Commercial fertilizers
shows % or pounds per cwt. (100#) of the three major elements in large numbers on the container or bag.

30. Commercial fertilizers
5-10-5
5% N, 10% P, 5% K
remaining 80% is filler
NP&K are always listed in that order.

31. Soil tests determine amount of elements needed for various plants.

32. How to take a soil sample
Take random samples from the area to represent the area you want to test.
Mix all samples together.
Take a sample from the mix of about 16oz of soil.
Complete soil test info sheet.
Mail to a reputable lab.
Analyze results and make decisions.

33. Nitrogen has most noticeable effect on plants
encourages above ground vegetative growth
regulates use of other elements

34. Too much Nitrogen lower disease resistance
weaken stem because of long soft growth
lower fruit quality

35. Too much Nitrogen
delay maturity
increase winter damage to plants

36. Not enough Nitrogen yellow or light green color
stunted root and top growth

37. N lost easily from soil
leaching - being filtered down through soil with water
not held by soil particles, dissolved in water
O.M. holds insoluble N for slow release

38. Nitrogen Deficiency in Corn

41. Phosphorous
held tightly by soil particles
not easily leached

42. Phosphorous effects plants in several ways encourage cell division
flowers and seeds don’t form without it
hastens maturity, offsetting quick growth caused by N.

43. Phosphorous encourage root growth makes K more available
increase disease resistance
improves quality of grain, root and fruit crops

44. Insufficient P purple color on underside of leaf
reduced flower fruit and seed production

45. Insufficient P susceptibility to cold injury
susceptibility to plant diseases
poor quality fruit and seeds

49. Potassium modifies both fast soft growth of N and early maturity of P
is essential

50. Potassium increase disease resistance encourages healthy root systems
essential for starch formation

51. Potassium
development of chlorophyll
efficient use of CO2

52. Insufficient K
leaves appear dry and scorched with irregular yellow areas on the surface

55. Lime CaCO3- Calcium Carbonate acts as a plant food
affects soil acidity – raises pH!
soil acidity affects availability of plant food elements

56. Lime
furnishes Calcium

57. pH measure of acidity or alkalinity pH scale - runs from 0 - 14
most plants grow best from

59. pH 7.0 is neutral pH of 7 or above is alkaline or basic
pH below 7 is acidic

60. pH as numbers decrease, solution becomes more acidic.
As numbers increase, solution becomes more basic or alkaline

62. How do we apply fertilizers?
Apply granules
Apply a liquid
Applying liquid through
water system
Broadcast
Band
Container treatment

64. Above ground environment
temperature
some plants prefer cool weather
some plants prefer warm weather

65. Temperature
there are temperatures above and below which plants stop growth
generally, plant growth rate increases as temps increase up to about 90 degrees

66. Light must be present before plants can manufacture food
plants vary in light requirement
effects flowering

67. Photoperiodism
response to different periods of day and night in terms of growth and maturity

68. Photoperiodism short day plants chrysanthemum and Christmas Cactus
bloom when days are short and nights are long

69. Photoperiodism long day plants lettuce and radishes
bloom when days are long and nights are short

70. Photoperiodism day length indifferent
do not depend on length of light or darkness
African Violet and tomato

71. Phototropism
plants appear to grow towards the sun or light source

72. Humidity moisture level of the air most plants grow best in 40-80% RH
Relative Humidity

73. Humidity
too high humidity may cause the spread of fungus diseases

74. Plant diseases and Insects
reduce production
lower fruit and vegetable quality

75. Soil
composed of sand, silt, and clay, organic matter, living organisms, and pore spaces

76. Soil
classified according to percentage of sand, silt, and clay they contain.

77. Soil Particles vary greatly in size sand - largest silt - medium
clay - smallest

78. Sandy Soil silt and clay make up less than 20% by weight drain well
little water holding capacity

79. Textural triangle

80. Clayey Soil must contain at least 30% clay
holds more moisture than is good for plants
poor drainage

81. Loamy Soil
most desirable soil
equal parts sand, silt and clay

82. Soil Profile
consists of 3 basic layers
topsoil
subsoil
soil bedrock

83. Topsoil
represents depth normally plowed

84. Subsoil
deep rooting plants send roots down into subsoil

85. Soil Improvement Drainage change soil structure
add organic matter to encourage earth worms

86. Moisture retention adding organic matter (o.m.) sources of o.m.
animal manure
green manure - crop grown and plowed under to improve the soil

87. Sources of O.M.
peat moss
sawdust
mulches - compost or wood chips

88. Mulches placed on the surface to help retain moisture
reduce runoff and evaporation
reduce weeds

89. Diseases plant resistant varieties chemicals soil pasteurization
heat to 180 degrees F for 30 minutes.