Vermicomposting
Rhonda Sherman
NC State University
Vermicomposting
• 30 days
• Mesophilic
• Passive aeration;
no turning
Composting
• 3 – 9 months
• Thermophilic
• Requires aeration
or turning
Compost sells for
~$30 per cubic yard
Vermicompost sells for
$400 - $1,250 per cy
Photo courtesy of Tom Herlihy, Worm Power
Plant Growth, Disease & Pest
Suppression
• Accelerates germination
• Increases growth, flowering, and yields
• Usually independent of nutrient availability
• Decreases attacks by plant pathogens, parasitic
nematodes, insects
Turnips Grown With
0%, 10%, 20% Vermicompost
Disease Suppression Rating
Pythium Suppression
4.0
3.5
Control
a
Sterilized VC
ab
b
3.0
Unsterilized VC
b
2.5
2.0
c
1.5
c
c
1.0
SMM
SMM + SMM + SMM + SMM + SMM + SMM +
10%
20%
40%
10%
20%
40%
SVC
SVC
SVC
VC
VC
VC
Pythium symptom suppression in cucumber seedlings planted in a soil-less medium
(MM360) substituted with vermicompost, inoculated with Pythium (mean ± SE).
SMM is sterilized MM360, VC is vermicompost and SVC is sterilized vermicompost.
Plants received all needed nutrients.
Courtesy of Dr. Norman Arancon; research conducted at Ohio State University
Effects of Vermicomposts on Mealy Bug
Infestations on Peppers
Number of mealy bugs per plant
80
70
60
50
40
30
20
10
0
0
20
40
Percentage Vermicompost
100
80
Percentage MM360
60
Courtesy of Dr. Norman Arancon; research conducted at Ohio State University
Vermicomposting is a process
that relies on earthworms and
microorganisms to help stabilize
active organic materials and
convert them to a valuable soil
amendment and source of plant
nutrients.
It is a mesophilic
process that should
not heat up.
Vermicomposting Process
• Maintains wide diversity of mesophilic organisms
throughout process
• Earthworms ingest microbes; some are digested,
others pass through gut unharmed
• Grinding action of earthworm’s gizzard promotes
microbial activity in wastes as pass through gut
• Eisenia fetida has indigenous microflora in gut that
contributes to microbial community in castings
• Mucus from intestinal tract covers castings
– Provides carbon source for soil microbes
– Leads to flush of microbial activity in fresh casts
• >9,000 species of earthworms
• ½ inch (2.54cm) to 22 feet (6.7 meters) long
• Must use correct species for
vermicomposting
Eisenia fetida is #1
• 1 pound (0.45 kg) = ~1,000 E. fetida
• Add 1-2 lbs (0.45 - 0.90 kg) worms to 1 sq ft
(929 sq cm) surface area of bin
• Eat 25-35% of body weight daily
• Do not get from yard or bait shop
– Would need 33 - 40 bait cups
• Buy from a worm grower
• Prices vary widely ($22 - $50 lb)
Important to E. fetida
• Temperature: 55°–83°F (limits 32° – 95°F);
15º-25ºC (limits 0º-35ºC)
• Moisture: 80% (limits 60 - 90%)
• Oxygen
• pH: 7 (limits >5 and <9)
• Ammonia and Salt Sensitivity
Vermicomposting Basics
• Start with ~6 inches (15.24cm) bedding
• Add composting earthworms
• 1-2 lbs (.45-.90kg) per sq ft (929 sq cm)
• Apply 1 inch (2.5 cm) layer of feedstock
• Wait until feedstock is eaten before adding more
• Cover food scraps with shredded paper, cardboard,
cloth, plastic, tarp, etc.
Feedstocks
• Income or Expense?
• Herbivorous animal manure, vegetative food
residuals, spent grain, yard debris, cardboard,
paper waste
• Pre-composting often takes place prior to
vermicomposting
Space Needed
• Collect/store feedstock
• Worm bins up to 8-ft (2.44-m) wide
• Length: depends on your limits
• Area to chop/grind food
• Place to pre-compost?
Organic matter
consumed by
worms passes
through their
digestive tract and
is excreted as
castings. We call it
‘Vermicompost’ to
acknowledge
undigested
particles of food
and bedding.
NCSU’s 17th Vermiculture Conference
– Benefits & uses of vermicompost
– Vermicomposting technologies
– Vermicompost research studies
– Marketing products
– Testing vermicompost, soil and feedstocks
– Brewing and using vermicompost tea
www.bae.ncsu.edu/workshops/worm_conference/