Intro & Physical Properties of Container Media

Question 1

Sphagnum Peat Moss

Answer 1

found in bogs and marsh lands
uses/stregths: potting media, water holding capacity, sterile, slightly acidic
limitations: expensive, high environmental impact

Question 2

Coir Fiber

Answer 2

husks of coconuts
uses/strengths: starting seeds, potting media, balances porosity, rot resistant
limitations: overseas shipping, supply chain issues, salt buildup

Question 3

Conifer Bark

Answer 3

shredded/chopped bark (fir/pine trees)
uses/strengths: potting media, aeration, organis, renewable
limitations: breaks down (needs to be replaced)

Question 4

Sand

Answer 4

uses/strengths: potting media mix, aeration, good drainage
limitations: poor moisture and nutrient retention

Question 5

Perlite

Answer 5

inorganic material (heat expanded pumice stone)
uses/strengths: media mixes, increases aeration, welldraining, hydroponics, lightweight
limitations: non renewable source, use PPE

Question 6

Pumice

Answer 6

inorganic material (volcanic stone)
uses/strengths: increases porosity, topdresssing, reduces compaction, high water retention
limitations: can be expensive

Question 7

Vermiculite

Answer 7

mineral material (heat expanded mineral product)
uses/strengths: high water absorption, bulb storage, amending heavy soils, neutral
limitations: too water retentive, health hazard

Question 8

Composts

Answer 8

uses/strengths: media mix. increased aeration, increased microbial activity, nutrients, renewable resource
limitations: site for composting, time to break down, weed seeds/pathogens

Question 9

Rock Wool

Answer 9

spun fibrous inorganic material (basalt)
uses/strengths: hydroponics, common growing media, lightweight, decreases potential for p&d
limitations: treatment for ph, expensive, high environmental impact, PPE, rarely used.

Question 10

Hydroton/LECA

Answer 10

expanded clay pebbles (inorganic) kiln fired
uses/strengths: semi hydroponics, topdressing, durable, reusable, reduces pest infection
limitations: expensive upfront, presoaking

Question 11

Steralized Soil

Answer 11

treated soil (industrialized)
uses/strengths: staerting seeds, optimal for greenhouses, cost saving, reduces competition
limitations: additional costs, chemical treatments

Question 12

Dolomite Lime

Answer 12

crushed/ground limestone (inorganic)
uses/strengths: raises pH (basicity)
limitations: adds too many secondary macros

Question 13

Turface MVP

Answer 13

highfired clay (angular/lightweight)
uses/strengths: potting mixes, topdressing, balances drainage
limitations: can be too dry/wet

Question 14

Grit

Answer 14

coarse/angular sand
uses/strengths: added to soil mixes, supresses weeds, improves drainage, inexpensive, does not break down
limitations: heavy, low water holding capacity

Question 15

Wetting Agents

Answer 15

surfactant (alcohol/petroleum distillates, soap, agar agar
uses/strentghs: rehydrating hydrophobic soil, improves infiltration and retention of water
limitations: lasts one month then reapplication required

Question 16

Volume of Growing Media Contains

Answer 16

growing media particles
water
air space
roots

Question 17

More Porous Media

Answer 17

holds less water
contains more air
dry out faster

Question 18

Less Porous Media

Answer 18

holds more water
contains less air
drys out slowly

Question 19

Total porosity

Answer 19

total amount of pore space in soil/growing media

Question 20

Saturation point

Answer 20

point at which all of the pore space in a soil/growing media is filled with water

Question 21

Gravitational Water

Answer 21

drainage water that exceeds the growing media’s ability to retain it

Question 22

Field capacity

Answer 22

the point at which the growing media’s ability to retain water is at maximum

Question 23

Aeration porosity

Answer 23

the amount of air space in the growing media at field capacity

Question 24

Water Holding porosity/capacity

Answer 24

max amount of water that a growing media can hold at field capacity

Question 25

Permanent Wilting Point

Answer 25

point at which the small amount of water in the growing media is so tightly held that it is unavailable to plants, resulting in death

Question 26

Hygroscopic Water

Answer 26

at permanent wilting point, this is the water that is too tightly held to be available to plant roots

Question 27

Available Water

Answer 27

amount of water btwn permanent wilting point and field capacity

Question 28

Total porosity formula

Answer 28

amount of water added to the media to bring it to saturation point

Question 29

aeration porosity formula

Answer 29

aeration porosity expressed as a percentage: 100 x (gravitational water/sample volume)

Question 30

water holding porosity formula

Answer 30

total porosity - aeration porosity