Worming 101

~Feeding the worms - Diet~

Aallonharja's recommendations for trouble free wormy diet

Plant-sourced material only. Wastes from fruit, vegetables, berries, tea bags, paper/cardboard/tissues. Not only do these contain a lot of nutrients like P and K, but it seems to me that worm castings made with this kind of feed make for sweet vivid taste and high trichome content!

Know your limits! Experiment with 'new' foods.


Do earthworms need a complete diet, or can they survive (and be productive) on a single unbalanced source of food, very high in N, P, or K?

I think that composting earthworms can survive on a single food source, BUT that food source must contain at least minute amounts of the minerals they need.

For example, only paper or only cardboard would support a worm population very well. But they do need a bunch of minerals just as we do to survive. I'm guessing nitrogen, calcium, phosphorus and magnesium would be the most important ones just as they are for us.

Earthworms do not actually eat the food materials themselves, but the BACTERIA that are feeding on the materials. These bacteria do the work of extracting the minerals and making more complex organic compunds for the wormies, like amino acids and vitamines and what not.


What foods need to be avoided?

Salt. Salt kills worms. Do not add any foods with high salt content into the bins. Often breads and processed foods contain high salt.

Cat and dog manure. Humanure. These can act as a vectors for human diseases, such as toxoplasma, the brain cell parasite, and thus may not contribute positively to your health in the long term. Manure from livestock should be safe to use (ie. horse/cow/sheep/poultry manure).

Generally it is thought that worms can process ANY organic material, given enough time to adjust. From pH 2 wineyard waste to actively 'hot' decomposing horse manure - but they will need time to adjust to the conditions, and the worm farmer will need to create suitable conditions. Experiment carefully.


Does the material have to be partially decomposed already?

Not at all. While in commercial operations the waste material is often 'pre-decomposed' or 'pre-composted', it is perfectly ok to add undecomposed organic waste such as fresh vegetable peels in a worm bin. One just has to watch out not to create a thermophilic compost that heats up and cooks the worms.

While the earthworms can only 'eat' material that has already started decomposing, usually adding fresh veggie waste, for instance, poses no problems whatsoever, especially if buried in the bedding.


My question is should I run my kitchen waste through a blender before adding it to the bin, or can I just chop it finely with a knife.

If you run the kitchen waste through a blender it will be consumed much faster - but chopping with knife would work quite well. I think blending the waste might halve the time required for decomposing.

I dont process my veggie waste, just throw them in there. I have 3 main bins with 8 month cycles, 6+ months of feeding and 2 months or less of settling. Once the cycle is through, the worm caste is dark brown muddy pudding that sticks to everything.


Whatabout adding sand? My kitchen waste contains no sand!

Sand - and grit - important, but also not a absolute must in my humble opinion. It helps the worms digestion, and it helps breaking down the organic matter.

For sand one can, in my opinion, substitute eggshells, perlite or dolomite lime. Sand is basically broken down inert, hard, rock-like material, so I suppose anything inert and hard would work. Do not use metals or plastics.

One doesn't need that much grit, and note that sand will concentrate on the bottom of the bin due to weight, so the top layer wouldn't have that much sand. I would say that sand content of one percent would be just fine.


There are all kinds of critters in there!? Can I harvest or should I wait?

A worm bin or a worm farm may support many kinds of creatures, mostly useful ones. But the fact that you can see that other decomposers are present usually means that the feed/waste has not yet decomposed very well, and needs some more time to become worm castings (unless worm compost is what you are after).

Usually critters like mites, springtails or tiny white Enchytraeid 'potworms' are feeding directly on the foods present. Unlike composting worms, they cannot survive by eating the bacteria present in the worm castings, and thus they will die off as soon as the foods have been decomposed.


Could I possibly add my soil fertilizers like kelp, alfalfa, and guano to the worm bin to up it's NPK. That way, my worm shit would be the only thing I needed to use for fertilizing, make a tea for every watering.

Yes, very much so. But with some ingredients its best to only use them for the final soil-mix because of their cost or composition. Kelp and guanos are both very very costly to be used as worm food.

As to using worm bins to process different food-wastes into different nutriens like veg or bloom nutrients, it works quite well, but often nitrogen and magnesium supplementation seems to be a requirement.

Worms like alfalfa meal, but one must not use too much at once as the high nitrogen content might cause heat-composting or even fermentation.

I think perlite that has spent some months in a worm bin would have lively bacterial cultures on its surface - yet another benefit..

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The Two Golden Rules Of a Worm Farmer

1. Know Your Limits

A worm farmer must know how much of feed and what kind of foods and wastes a worm bin can process. Overfeeding is basically the only thing that can kill off the worms (too high protein levels -> composting or 'sour bin disease'). Salt, pesticides and drugs can also kill off worms. So know the limits for food intake and experiment carefully.

2. Leave it alone

Leave them alone - they like it like that. If you really must work on worm farming, just start a NEW bin. Or how about another spliff of the sweet flavoured worm casting grown..

Do you need to mist a worm bin from time to time to keep it moist?

Not really, as the vegetable waste seems to contain enough moisture to keep things moist and juicy. Sometimes one has to add a little water.

But a worm bin should contain a lot of moisture. A 50% to 85% saturation (of the full saturation) favours the worms growth, digestion and breeding. If a bin gets too dry, one can add water by spraying or sprinkling (or however).

What if it gets too soggy in there?

Often a worm bin gets too moist. But if you add the a newspaper on top, in two, three days it will soak up the excess moisture and can be removed. Repeat until desired moisture content has been achieved.

Do you cover a worm bin or does it need some light?

Yes, all my bins have covers or lids. A worm bin doesnt need any light, in fact worms are afraid of light and will avoid it. Most worm species are very adventurous and will roam around for no particular reason, and if my bins didn't have lids they might leave for excursions.

Do you move your bin around from time to time or just leave it alone? Do you turn the bedding?

Its best to leave it alone. Worms move the bedding and castings about. Turning or moving isn't needed, and might bother the worms... but Im a nervous little chimp so I 'dig in' at times to see whats going on.

What are the conditions that will cause them to die off?

Worms will produce castings in a very wide window of environmental conditions.

Freezing or human fever temperatures will cause worm deaths. They also need oxygen to breathe, and they do not like poisons or pesticides, although they can eat many things like motor oil.

Most often a worm bin will die off because of inadequate ventilation or because the organic waste starts to 'heat up' from the bacterial action, cooking the worms.

There are mites in there! Do I need to DDT the house to protect my plants?!

No. The mites in a worm bin are either decomposers or predators and do not eat plants (if they were after plants they would not survive in the bin).

Worm farm/bin mites can be controlled by lowering the moisture levels, and are often a sign that the farm/bin is too moist. Red and brown mites are usually predators, some even attack the worms and suck their blood. Usually mite populations in the bins are not a problem, and will die off the farm/bin is no longer being fed.

What are those strange insects in the bin?

It is common to come across fruitflies, Mites (Acarina), threadlike white worms (Enchytraeidae), springtails (Collembola) and sow bugs (Isopoda). Outdoors an unprotected bin will attract worm-eating pests like land planarians, rodents and birds, so suitable measures should be taken.

How often do they reproduce?

Worms will start reproducing as soon as they are mature. The reproductive cycle for composting worms is about 100 days.

A worm population can grow exponentially in size given enough room and nutrients. I find its quite easy to double population size very 4 months.

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I want to start a worm bin...Not only for the castings but we have a turtle that eats night crawlers and I hate buying worms...so I'm gonna get a plastic tub and I'm gonna drill a lot of little holes in the bottom and in the sides. I'm gonna put some shredded newspapers and peat in there....am I good so far? When do I put the worms in?

Yes, your plan is foolproof.

After you have a well ventilated bin with some bedding, you need to moisten the bedding.

After the bedding has been moistened, you can add the worms. I would let them settle in for some days or a week with just a little something to feed on.

Once you see they are eating/have eaten that something, start adding more waste/food in small amounts, maybe once or twice a week.

In a month or two you will be a master worm farmer!


What do I need? (to make worm castings?)

All you need is a worm bin, basically a plastic or wooden box, and some composting earthworms (from worm-/garden-/fishing store, or from a recent compost pile or a windrow). Red Wrigglers seem to multiply very fast when fed with paper mulch & ground up kitchen waste -mix. They're not picky, recommended for vermicomposting!!


How to build a worm bin?

Basically you take a container of some kind, with a lid, drill a lot of tiny holes in it for aeration and some on the bottom for drainage. Place this box, bucket, tub, bin, what have you, on a tray, and you have a worm bin.

I prefer to use recycled food boxes made of PE or PP plastic. These can be had for free in all sizes and shapes at cafe's, restaurants and supermarkets.

I like a nesting box of design, where one box acts as the worm bin, and the other as a tray (inner is the bin, other is the tray). See the attached drawing.

Shallow worm bins and farms work best, with maximum depth of 30 cm (12").

Please also see this perfect thread in the organic foods forum - "How to build a worm bin?": www.overgrow.com/edge/showthread.ph...37&pagenumber=1


Where can I find worms for a worm bin?

You can buy them or look for them in nature. You will need to find surface dwelling composting worms.

In urban settings, the most common place you can find composting worms is the fishing store, where they are sold as bait. Common names are Red Wrigglers, Red tigers, tiger worms and earthworms. Also your local nursery or gardening center might sell them. Recycling centers and urban developement project centers also sell and hand out composting worms. Finally there is the internet, where a local worming resource can often be found.

In nature, composting worms like to spend their time in the surface litter, in compost piles and manure piles, wherever there's decomposing organic waste on the ground. The worms you are looking for are smallish and spend their time in the top layers of the litter. Please respect nature and dont wreak havok on the worm populations!


How deep should the compost be to encourage worm production?

A shallow composting bed works the best. In nature composting worms live on the very surface of the soil. I have found compost bins that are under 30cm (6 inches) deep to provide best environment for the worms.


How many worms does it take to decompose a box of bedding 3 foot square by 1 foot high?

3' x 3' x 1' box would contain some 64 gallons, or 240 liters of bedding. By numbers this bedding could perhaps have twenty thousand worms, and could maybe support up to a quarter million worms.

Worms are usually measured by volume. A liter of worms is often thought to contain an average of one thousand worms, weighing close to a kilogram.


Why bedding? What is the best material to use for bedding?

The purpose of bedding is to act as relatively neutral medium, to prevent composting heat-up (thermophilic bateria) and provide home for your worms.

There are many materials that will work well for the bedding. Shredded paper, cardboard, peat, coco coir or clean healthy gardening soil will all work very well.


I've never understood the difference between bedding and food. They eat both eventually, so why put food in there in the first place?

Well... Bedding is sort of like the water in juice - if you had to drink juice concentrate, it would burn! It also acts as a neutral safe zone for the worms, in case the fresh food isn't to their liking (so it will have to decompose for some time in the bedding).

In other words, bedding is for worms the same as the sea is for fish.

Usually the worm food is buried in one corner or side of the bedding. This way the bacteria start working on the food immediately, the food doesn't attract pests (house and fruit flies usually), doesn't smell in any way, and in case the worms dont like it they can easily move away from it.

Without bedding, the worms would have to live in pure food, which would at first start heating up, as there would be no bedding to 'cool down' the bacterial activity.

Bedding is usually very high carbon material. Worm foods are usually higher in nitrogen. High nitrogen materials heat up easily, but the bedding prevents this, so bedding works in many many ways.

What can I use as a feed for a worm farm?

When you start, it is best to use newspaper. Ordinary daily morning paper. Make sure that the inks used do not contain heavy metals by contacting the paper. Newspaper will never cause any problems, and the worms love the paper and the soy based inks. Do not use glossy magazines.

Generally anything that is organic and non-toxic to worms can be used as a worm farm feed. Anything that one would put in a ordinary compost bin. Worms will process almost anything, given the right conditions and adjustment period. Experiment with 'new' foods carefully. See mainteinance and reference sections for more on feeds.

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NPK Nutrient values for some common worm foods

High N:
Blood Meal (NPK 13-1-0)
Coffee grounds (NPK 1,99-0,36-0,67)
Felt (NPK 14-0-0)
Hair (NPK 14-0-0)
Tea grounds (NPK 4,15-0,62-0,4)
Worm Meal (dried & ground worms) NPK 10-1-1
Greens, leaves & meals, alfalfa, stinging nettle

High P:
Bone Meal generic NPK 4-21-0,2
* steamed NPK 13-15-13
* burned NPK 0-34,7-0
Shrimp Waste NPK 2,87-9,95-0
Tea Leaves ash NPK 0-1,66-0,4
Wheat bran NPK 2,65-2,9-1,6
Oats, Chicken Manure

High K:
Banana skin NPK 0-3,08-11,74
Molasses NPK 0,7-0-5,32
Potato skin NPK 0-5,15-27,5
Wood Ash NPK 0-0,15-7,0
Wood ash (broadleaf) K 10%
Wood ash (coniferous) K 6%
Alfalfa, ashes, potato wastes, peel & skin (-ashes, too)

High Calcium:
Poultry manure (0,5-0,7% dry), dolomite lime, egg shells, bone meal
Note that its usually thought that worm castings is high in calcium (perhaps with the presumption that lime or eggshells are added during the process).

High Iron:
Stinging nettle (Also high N)

High Magnesium:
Dolomite lime, poultry manure, epsom salts


Vermicomposting by Numbers

Facts from a technical compost quide, section 'Vermi-stabilization' (of composted communal waste). (Komposti, WSOY 1984).

They are talking about the red wriggler Eisenia Fetida:

• Optimum pH range 5-8. The worms die under pH 4,5 and over pH 9.
• Optimum Humidity 80-85%.
• Dissolved salt leves should not exceed 0,5 % (5000 ppm?). Ammoniumacetate is toxic to the worms when concentrations exceed 0,1% (1000ppm).
• Greatest growth rate in temperatures between 20 and 25 C degrees, greatest feeding rate in 15-20 C degrees. Temperatures above 37 C degrees cause worm deaths. Can adapt to live in temperatures close to 0 C degree.
• "Its been theorized that with optimum temperatures and sufficient food source the worms would achieve maturity in 5-9 weeks, meaning that a population of 100 worms could produce an offspring population of 250 000 worms in a year."
• "..up to 20% of the waste materials weight can become wormbiomass ." (worm biomass is the worms themselves, not the worm castings)
• "The will never be a problem with overproduction of worm- biomass, as the worms can always be dried and ground to produce a plant fertilizer. The NPK value of the dried worms is approxemately 10-1-1. The worm-biomass also contains 0,8% sulphur, 0,6% calcium, 0,3% magnesium and minerals that benefit the growth of plants."


Worm Species Data

Eisenia fetida (foetida)/Eisenia andrei
Common names: redworm, tiger worm, manure worm

Maximum reproduction under ideal condtions:
3.8 cocoons per adult per week
83.2% hatching success rate
3.3 hatchlings per cocoon
Net reproduction of 10.4 young per adult per week

Maximum growth rate under ideal conditions:
32-73 days to cocoon hatch
53-76 days to sexual maturity
85-149 days from egg to maturity

Temperature requirements °C (°F):
Minimum 3°C (38°F)
Maximum 35°C (95°F)
Ideal range 21-27°C (70-80°F)

Eisenia hortensis (Dendrobaena veneta)
Common names: Belgian nightcrawler, European nightcrawler

Maximum growth rate under ideal conditions:
40-128 days to cocoon hatch
57-86 days to sexual maturity
97-214 days from egg to maturity

Temperature requirements °C (°F):
Minimum 3°C (38°F)
Maximum 32°C (90°F)
Ideal 15-21°C (60-70°F)

Heat tolerance is dependant on moisture level. This worm is very tolerant of environmental fluctuation and handling, but has a slower reproductive rate and requires very high moisture levels, relative to other worm species.


Other common composting worm species[b/]

Bimastos tumidus - often found in compost piles, tolerates medium C:N ratios and cooler temperatures better than Eisenia foetida , multiplies rapidly in old straw and spoiled hay, hardy to Z-5 and will survive in ordinary soil conditions hence once established it would survive without extensive preparations. Earthworm Ecology and Biogeography in North America

Eudrilus eugeniae: (African nightcrawler) do well but cannot withstand low temperatures.(composter or surface worker species)

Lumbricus rubellus: (common redworm or red marsh worm), used in Cuba's vermicomposting program, (composter or surface worker species), native to U.S.

Lumbricus terrestris: nightcrawler, native to U.S. Not suitable for vermiculture.

Perionyx excavatus: (Asian species) do well but cannot withstand low temperatures. (composter or surface worker species).

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When to harvest?

In my bins, the finished worm castings are actually dark brown muddy paste. There are no other visible decomposer insects present, and the worm population also has usually started to decrease in size, imho. This happens usually one or two months after I stop adding more food in the bin. Note that I am talking about non-juiced/ground foods here.


How do I/you/we harvest castings?

There is the Scoop-Off-Thin-Surface-Layer-While-The-Worms-Head-Downwards-In-The-Bin-technique.

A handy one, especially for harvesting worms, is the Lure-The-Pink-Wriggly-Workhorses-Into-A-Disposable-Plastic-Box-With-Sum-Fresh-Banana-Peels-tech, this takes 2 or 3 rounds before basically all over 2 week old worms are harvested.

The first one above is ok for small bins. The second one will work with larger ones, but you will need to add more plastic-box-trap-containers if the bin is large.

For big jobs, its best to use a worm harvester made of stainless steel screen. Its basically slightly tilted rotating cylinder made of screen with a 'solid wall' end that you gradually dump the bin contents into. The processed caste falls to the collecting box under the harvester, while the worms roll downhill inside the cylinder into the solid-walled 'collector'.


Is there any way to get everybody out of the castings before they're harvested?

Yes, in my opinion there is. Food lures! The worms will go after moist white bread or banana peels like a rasta for ganja!!

As worms can use their sense of smell to track down worm-treats, and move actively after foods, using food lures works very well, especially so in a mature bin where fresh food availability is low.

Combined with some kind of simple mechanical trap this works very well, and very few worms will stay behind.

A wormer by the OG name of 'Aprilfool' introduced this simple concept:

The method that I use for seperating worm from the bin is something I call worm wrangling. When the bin is about two months old I don't feed them for a week or two then place a slice of bread on top. In a day there are hundreds of worms under the bread that are easily scooped with a trowel and placed in a new bin. I do this for a week. Then I leave the rest of the worms to finish the food that left in that bin. In about another two months there are few worms and all castings, in that bin.

I have four bins.

In a tray system, or a box-in-a-box type of worm bins (where the outer box acts as a leachate-juice tray) one can simply add the food lure in a empty tray and after some days most of the worms will be in that tray, and can be collected. Repeat once or twice and you should have helped almost all hatched worms in the bin to emigrate.

Or one can simply bury some kind of empty container so that its mouth is flush with the worm castings surface and drop a worm treat in the container - since the worms have easy access to a fresh food source they will congregate in the container.

Remember to keep things moist so that worms and their food lures wont dry up.

There are other ways - like you mentioned, drying the vermicaste will motivate the worms to find more hydrated surroundings. I guess one could use citrus peels as a repellent to drive them out.

Of course, getting the cocoons (the worm eggs) out would require hand sorting or a mechanical cocoon separation machine.


I wonder how long the new generation would survive in pure castings. maybe you could let it sit until they die-off. - SatGhost

Well, many worm farming guides and companies say that the worms will eventually die in 'finished' worm castings.

I have not seen this happening in 'finished' worm castings. Also Mary Appelhoff, 'The Worm Woman', US worm movement 'spokesperson' says that worms will survive indefinitely in worm castings. I think that well made worm castings will always contain at least few worms, unless separated mechanically or otherwise.

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~Using worm castings~

How to use worm castings in a soil mix?

Worm castings can be used in a multitude of ways - mixed into a soil mix, a soilless mix, or as a tea or slurry.

Usually worm castings is thought of as an additive. Recommendations vary wildly, but I would recommend adding one tenth to one fifth in any organic mix (10-20%).

Top dressing with worm castings would work well, too, especially with indoor containers. Making a worm castings tea by steeping the castings in clean well aerated water makes for a life giving plant-nutrient. I recommend filtering worm tea before use and returning the dregs into the worm bin after a couple of rounds.

One can use plain worm castings as a growing medium, and in my experience it works very well. But usually finished worm castings tends to be mud-like in consistency, and needs something to aerate and lighten up the texture. Perlite and expanded clay work very well for this. 50% of expanded clay (multiple size) and 50% worm castings makes for a nice quick-n-dirty primo soil(less) mix.


The Classic Shabang Mix

"The mix that I recommend is basically nothing but castings and drainage. I used to cut it with all sorts of things, including soilless peat-based mixes like pro-mix.. but then you're introducing a source for pH problems-- especially when others try and duplicate it but can't find the right brands then substitute with a peat-mix that is too acidic. So down to the bare basics of a mix:

40% castings
30% perlite
30% vermiculite"


102% Hyper Veg Mix by Aallonharja


* 25% coco peat
* 25% expanded clay
* 50% worm casting
* 2% alfalfa meal pellets
* 1/4 tablespoon of dolomite lime per liter (1 per gal)
* lemon juice (or 8% citric acid solution)
* seaweed extract according to taste
* silicon nutrient additive

Note:

- This is a guideline, not a recipe. Know your ingredients!

- If things get too sticky, muddy or water retaining with the worm castings, add more coco peat, peat, perlite or expanded clay.

- The stretching due to alfalfa can last up to 5 or more weeks.

- For alfalfa meal pellets 2% is a careful estimate. More can be used if the plants can take it.

- This mix should last about 4 weeks, ie. supply the plant with nutrients during the vegetative period, PK and N+Mg+Ca additive may be needed in bloom.


Meek Flowering Mix

* Worm castings, from bin fed with fruit and vegetables and peels (High K, Medium P)
* Optionally in the first 4 weeks of flowering, add as needed:
Pinch of dolomite lime or epsom salts
Pinch of gypsym
Pinch(es) of clean, pure wood ash


Mix in a bucket of water, and filter solids. Water during flowering.



Note:

- This is a guideline, not a recipe. Know your ingredients!

- Yields very vivid aromatic tones

- Basically a high K + P + Mg + Ca + S solution - all thats needed in bloom.

- N supplementation may also be necessary.


Oh also, you could talk a bit about Casting Tea aswell.

Well I've usually simply spooned some more or less finished castings into a cheapo nylon stocking and dumped that in a bucket and a reservoir.

A surefire way would be using 100% finished worm castings with a high quality filter material, and place that in a bucket with water, aerate the water for 48 hours, and then use that water for watering, provided it didnt contain visible pests and didnt smell like rotten fish (aerobic teas shouldnt smell bad in the first place).

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Last edited by Suby : 06-06-2007 at 08:56 PM. Reason: i'm a retarded frenchman who can't spell

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There are no foods that are considered toxic to worms, not even very acidic foods like tomatoes or pineapple, or those which contain protein degraders, like mango. All of these foods are routinely fed to worm beds very effectively.

The issue becomes murky when the ONLY food source going into the worm bed is one that is highly acidic, salty, or irritating, but when used in combination with other organic materials there is nothing that mammals can eat that worms cannot effectively process.

Beginner wormers most commonly get in trouble by over watering and over feeding. Worms can eat 1/2 their volume per day, sometimes more. However, you must build up to these levels, don't expect that immediately. Worms do great on any vegetable scraps or leftovers, if not too highly seasoned, especially salt. Garlic and onion are somewhat antibiotic, which is counter productive to your worms, but are good feed after composting, which apparently alleviates the antibiotic. Citrus peels seem to be too acidic for them until composted, but the pulp or fruit they love.

Egg shells are extremely valuable in your bins, as the calcium really enhances reproduction, and helps to adjust pH. It's my personal opinion the eggshells benefit reproduction partly due to the albumen content, as worm cocoons contain this as well.

There is a fruit stand on the island of Kauai that is processing all of their spoilage in an onsite worm bin, spoilage comprised of mangos, bananas, pineapple, coconut, mountain apples and other indigenous fruits. Again, this system is working beautifully. There are numerous worm systems in the pacific northwest, land of the coffee addicts, processing nothing more than coffee grounds (with some filters mixed in).

In areas of India, where vermicomposting is far ahead of us here in the US, they had to learn how to manage their foods so that they could be effectively used in worm beds because of the heavy use of pungent spices that would drive worms from the bed or kill them. Many Mexican worm composters had the same challenges, yet they discovered that by mixing with good bulking agents and allowing the material to do a bit of precomposting first the pungent, irritating constituents were remediated.

There are worm systems throughout the world processing post-consumer food waste, which is seriously salty stuff, with no problem at all (though the resulting castings tend to be high in salts).

The bottom line is that worms can eat ANYTHING that was once living or part of a living thing. There is no list of toxic foods because, well, there really aren't any.

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Description: Rice is the principal crop in the North Region of Rocha Municipality, and is produced in 55% of the Biosphere Reserve. After processing, the rice industry produces about 143,000 metric tons of rice hulls per year in the region. This crop residue is not utilized, and in most cases is burned. During 1994 and 1995, PROBIDES ( Biodiversity of Conservancy and Development Sustainable Program at East's Wetlands of Uruguay) conducted several experiments to obtain organic fertilizers by rice hull composting and vermicomposting, and to evaluate the effect of adding different sources of nitrogen and inoculum. The duration of this process was about 4 months. Using standard composting methods, rice hull degradation was not total (picture?), whereas in the vermicompost, rice hulls lost their structure.

Lessons learned: Worms can play a key role in rice hull decomposition, as rice hulls can be difficult to compost, with their high C:N ratio (~70), their high cellulose and lignin content, and their waxy surface cover that impedes microbial attack, due to its low capacity to absorb water. Using composts made by mixing rice hulls with manure contributes micronutrients and improves soil structure (more water and air retention). This is a good example of crop residue utilization and its transformation into a resource. Rice hulls, with their high lignin and cellulose content are a source of the precursors of humus, the organic matter component with the most stability and nutrient availability. At this time, people are adopting rice hull composting practices to obtain organic fertilizers, which are sold in this region for application in gardens, homegardens, parks, etc. This organic fertilizer is sold in bags made from recycled paper.

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