Horticulture Science
Unit A
Horticulture CD
Growing Media, Nutrients, &
Fertilizers
Problem Area 4
Understanding Properties of
Growing Media
Lesson 1
Vermiculite>>>>>
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Interest Approach
What makes a great
basketball team?
5 or more members that work well together.
At least 1 who can score points from 20’ +.
At least 1 who can be used inside the key.
1 or more who can control the ball.
1 or more to push the ball inside.
Each player has their strengths!
Interest Approach
What makes a great growing
medium?
• Several components that work well
together
• 1 or more that hold water.
• 1 or more that hold air.
• 1 or more sources of nutrients.
• 1 or more to help defend against pest.
– Components that are sterilized.
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Interest Approach
Which Makes the Best
Growing Medium?
Sand
Peat Moss
Field Soil
Vermiculite
Pearlite
Water
Gravel
Student Objectives
By the end of this lesson, you
will be able to:
• 1. Identify the types of growing media.
• 2. Describe the functions of growing
media.
• 3. Explain the relationship between
growing media and plant growth.
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
What are the types of growing
media used in floriculture
production?
• Is “soil” used?
• Soil – the earth’s outer crust is full of
life!
– Bacteria
– Fungi
– Invertebrates
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
So what media should you
use?
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Sand?
Dries to quickly.
Peat moss? Dries to slowly.
Coir?
Hard to get wetted.
Water?
To little air.
Pearlite?
To much air.
Vermiculite? Pricey.
Potting soil mixes? Just right.
The 3 basic types of media!
• Soil – natural layer of the earth that
supports life.
• Soilless – any material for growing
plants not containing topsoil.
• Hydroponics – plants grown primarily in
nutrient solution.
What are the functions of the
growing media?
• Must provide AIR.
• Must provide WATER.
• Must provide Nutrients.
• Must provide ANCHORE / SUPPORT.
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
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
Necrotic line patterns in the foliage of a cyclamen
affected by impatiens necrotic spot tospovirus
(INSV).
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.
Review
What are the 3 types of
media?
• Soil
– define
• Soilless
– define
• Hydroponics
– define
What are the functions of
growing media?
• Supply Air.
– Why?
• Supply water.
– Why?
• Supply nutrients.
– Why?
• Supply support / anchor.
– Why?
Why is it important for media
to:
• Supply nutrients?
• Increase healthy plants,growth and
returns.
• Supply air?
• Reduce diseases and increase profit.
• Supply uniformity?
• Plant schedules require uniform plant
growth!