Posted: 17/05/2016 at 23:25
Forwarded Email. That everybody should know if you love your worms!!!
"What is the nutritional content of and how to improve the
nutritional quality of vermicompost?" .
Thanks for the PM Hun.
I think I have to share thi9s one.
The quality of compost has been discussed before, especially ( Hot composting and cold composting and worm composting?).
There is a Huge difference and it depends where you live and your climate and what you have to feed the worms!)
Thanks for the question.
The short answer is "it depends", since different vermicomposts will have different nutrient contents. The primary determining factor when it comes to
compost nutrients is of course the starting material.
There is no doubt that a vermicompost made from paper sludge will have a different nutrient profile than one made from cow/horse manure and straw (other possible sources of shit available examples). For that matter, even different manure vermicomposts can have significantly different levels of nutrients, depending on the type of animals, what they were fed, what their living conditions were at the time etc.
The best way to ensure a fairly uniform nutrient profile in your worm compost is to use the same feedstock, in the same proportions, from the same source every time. But do make sure that they are not full of chemicals from crop spraying and other contaminants. ( we want it clean
With all that being said though, let me at least attempt to provide you with some idea of the nutrient content of vermicomposts in general. ( this is from old tests from American universities and new re tests. (Basically. old info I have, that has been re tested and proved right)
Here is a quote from my old files. Composting expert Dr. Scott Subler (from correspondence on a composting email group, that i have on record.):
"The reported range of nutrient contents in vermicomposts is quite wide, as it is in composts, although total N and P don't appear to reach levels quite as high as found in some composts (e.g., poultry litter composts). Vermicomposts based on animalmanure feedstocks typically contain 2-3% N (dry wt basis), with
slightly higher values reported for biosolids vermicompost (up to 3.5% N) and lower values (<2% N) reported for some food
waste vermicomposts. Available nitrogen often comprises a relatively high proportion of total N, with very low ammonium-N and very high nitrate-N being characteristic of many vermicomposts."
To back up what Dr. Subler says, here are some actual nutrient profiles for several types of vermicompost, as reported in a
couple academic studies: ( These NPK are true as i have tested them over years. Still can't find the right mix though.)
Pig Manure vermicompost % N/P/K/Organic C/Ca/Mg/Fe:
(Atiyeh et al. 2001)
Food Waste vermicompost % N/P/K/organic C/Mg/Fe:
Paper Waste Vermicompost % N/P/K/Organic C/Mg/Fe:
(Arancon et al. 2004)
So, while pig manure vermicompost seems to have more nitrogen and phosphorus, the food & paper waste vermicomposts seem to have much more potassium (K) and organic C. While this should at least give you some idea of what you can expect, these figures definitely aren't set in stone by any means. As far as boosting nutrient levels in composts and vermicomposts there seem to be a variety of options for doing so.
My thinking approach, from resent thoughts was (Ussery, 2007) involves growing certain species of plants known for 'mining' nutrients.
Horse shit/ Comfrey/ River sand (Micro nutrient) and some cardboard or new News paper.
JUST ADD THE WORMS!!!
Last edited: 17 May 2016 23:35:42