Propagation/Greenhouse Management
46 | Unit 1.3
Appendix 6: Propagation Media —
Ingredients and Properties Imparted
Appendix 6INGREDIENT FUNCTION/QUALITIES IMPARTED SOURCE COMMENTS/SUSTAINABILITY COSTS
Peat Moss Fungistatic/acidic, $$$, pH 3.5-5.0
H 2 0-holding capacity 10 times dry wt. Non-renewable
Perlite H 2 0 holding capacity 3–4 times wt., Mined silica, $$$, no CEC^1 , no nutrients
5–8 lbs/cu ft aeration, drainage volcanic origin
Vermiculite Drainage, High CEC, Mica from $$$, Heated @2000°F to
6–10 lbs/cu ft H 2 0-holding capacity 6–8 times wt., MT & NC expand water-holding capacity
has Mg/K
Compost Moisture retention, drainage, Produce Requires labor to produce,
nutrients, pathogen suppression weed seed
Soil Minerals, minor NPK, bulk density On-site Free, weed seed
Sand Drainage, aeration, Quarried/Sharp $, 0.05-2.0mm diameter,
no CEC or nutrients
Leaf Mold Serves as peat substitute, On-site Free, labor to harvest
(decomposed acidic/fungistatic, drainage,
leaf litter) H 2 0-holding
Coir Fiber H 2 0-holding, drainage From Sri Lanka, $$, hard to handle/break up,
Madagascar, non fungistatic
coconut
byproduct
Grape Seed Drainage, aeration Winery Time/labor, perlite substitute for
Pomace byproduct mixes, could have high potas-
sium
(^1) CEC=Cation Exchange Capacity (see Unit 2.2, Soil Chemistry and Fertility)
$$$ = expensive input
$$ = moderately expensive input
$ = low-cost input