1. Horticulture
Growing Medium

2. Types of Organic Media A – Sphagnum Peat Moss
1 – the remains of dead plant materials harvested from peat bogs
2 – 1/25th of an inch of compressed moss equals one year of growth
3 – Most is imported from Canada.
(only 5% of worlds supply is in the U.S.)

3. 5 – very high in pore space
4 – very high water holding capacity makes it important for horticultural use
a – weighs 6 ½ lbs. per cu. ft. when dry
b – weighs approx. 100 lbs when saturated
c – can hold 15 to 20 times their weight in water
5 – very high in pore space

4. B – Sawdust 1 – replacing peat in some areas
2 – certain trees contain harmful substances (walnut and ceder)
3 – bacteria that decompose sawdust rob the soil of nitrogen

5. C – Sand 1 – deep-mined white mountain sands are mainly silica
2 – free of diseases, seeds, and insects
3 – increases porosity

6. 1 – volcanic rock mined as an ore
D – Perlite
1 – volcanic rock mined as an ore
2 – heated particles expand like popcorn
3 – pH of 7.0 to 7.5
4 – improved aeration and drainage
5 – is dusty and does float

7. 1 – Mica-type mineral expanded by heating
E – Vermiculite
1 – Mica-type mineral expanded by heating
2 – flat plate-like mineral expands like an accordion but can be destroyed
3 – holds 500% water by weight
4 – high in potassium, magnesium, and calcium

8. F – Coconut Coir 1 – made of the outside shell from coconuts
2 – increases aeration and drainage

9. II – Composition of the Growing Media
A – Solid material
1 – approx. 50%
2 – organic or inorganic depending on soil type
B – Liquid
1 – approx. 25%
2 – too much water and plants become “water-logged”, causing fungus or fertility problems

10. C – Air space 1 – approx. 25% 2 – too much and soils cannot hold water
3 – too little causes restriction to rooting

11. III – Advantages of Soil-less Media over topsoil
A – consists of material with known properties
B – typically more consistent
C – easier to handle and mix

12. D – fertilizers and pH can be adjusted to desired levels
E – correct drainage and water-holding capacity are adjusted
F – sterilization is generally not required
G – cheaper to prepare

13. IV – Soil Moisture A – Three forms of water
1 - Gravitational Water – temporary and drains from a soil by gravity
2 – Hygroscopic Water – mostly in vapor form and unavailable to plants
3 – Capillary Water – water held between soil particles by capillary action

14. B – Field Capacity – the amount of capillary water that is available to plants after gravitational water has drained
C – Wilting Point – the amount of water present when plant starts to wilt; soil particles typically hold water with 15 atmospheric bars of pressure