Wet Compost Using Yeast or Lactic Fermentation (was Sustainable Slug Beer)




About: I am a stone mason. My hobby is making new solar cooking and gardening stuff. I have used solar heat to cook soil for a couple of years. In mother earth news in January, i read that their compost expert does...

This project has forked in several directions. I am currently fermenting dandylions (with a lactic fermentation) to produce gas bubbles to circulate water to plants. (This is called the biofueled pump)  When the fermentation is over, the fermented leaves and stems are then squished to try to get the fibers. The fibers will be used for "felt" fibre pots for plants.  (This may be in combination with hydrated lime to make felt fibre limestone pots).  The "acidic juice" will become compost tea to be circulated to plants to water them (Using the biofueled pump to provide the power.
Brian White May 2 2011
I failed so far to make a likeable slug beer from garden waste mixed with water.
But the yeast does seem to work to convert it through an alcoholic stage.
(Latest test was a 45 gallon barrel full of morning glory and seeding weeds).
Then it goes acid, and then a skin of mold forms over the mixture. A week or 2 of these staged anerobic conditions will hopefully kill off the morning glory and pickle the weed seeds in alcohol, then acid.
Below is the slug beer plan that has so far not worked. Anyway during the recent heat wave, the slugs have not even been interested in my good homebrew. (july 31 2009)
I make beer for the slugs in my garden but it is expensive. I think slugs are drawn to the hop smell and then they get drunk and fall in. Perhaps other flavourings will draw them too?
A few years ago I made plum wine for them (stronger than beer but they were not interested!).
It gave me such headaches that I thought it would appeal to the slugs but no)

Do slugs really care if the beer they drink is to top international taste standards? Lets try to make beer from weeds, vine cuttings, grass clippings, seedy weeds too.
Bread yeast is cheaper and widely available, lets use it instead of beer yeast.

Perhaps it can all be intigrated into the composting and mulching system for your garden.
I do not always get enough heat in my compost to kill weed seeds. Perhaps problem seedy weeds could be diverted to the slug beer process to kill them off?
Perhaps you could even intigrate it into your fertilizing system too. Yeast can convert nitrates into yeast protein.
Not quite organic gardening but a lot closer than just applying nitrate fertilizer directly to your plants.
I made my first batch from lawn mowings and tall grassy weeds
If your barrel of beer does go off, the next stage is weak acetic acid. If the alcoholic conditions did not get your weed seeds, perhaps the acid will!
I am too busy to give it enough attention.
Please try your own. Today, monday 20th July i checked real beer in saucers from last night and no slugs. (We are currently having a heatwave and dry spell)

Step 1: Start the Yeast

Bread yeast comes dried and you need to add it to warm sugary water to activate the yeast. After a couple of hours it will be foaming and froathy. I think a table spoon of yeast added to a half liter of water with a teaspoon of molasses and a table spoon of sugar already in will be a good starter.
A little flour is no harm either.

Step 2: Weeds or Grass Addition

I left my lawn mowings until it turned into hay and added it into a garbage can full of water. But you could add green weeds or grass clippings or kitchen scraps either.

Step 3: Water, Sugar and Activated Yeast Into the Garbage Can

I added water to the can and dropped in 3 or 4 kg of sugar to provide energy for the yeast and some molasses too

Step 4: 3 or 4 Days Later, Beery Smell!

The weeds and grass were at the top of the can(due to the bubbling) and it had a smell of fermentation!

Step 5:

Next stage, mold on top and vinegar smell
Well, I came home from work one day and the hay had trapped the CO2 bubbles from the yeast , raised to the surface and pushed the lid off the can. So I put in a large rock on top of the hay to keep it down. I expected it to slowly sink but it did not.
I presumed the slug beer experiment to be a failure at that stage, A day with insects getting in and all sorts of contamination. But might as well let it run its course.
A light mold soon grew on top but the vinegary smell still remained. I will date the pictures later.
See what happens next on the next step.

Step 6: Results?

I put my beer (early on before the lid popped off) in little cups and saucers round my vegetables.
The first batch did not attract any slugs, though earwigns and wood bugs seemed to be more fond of it than they are of ordinary beer.
I put a control of ordinary beer out (slugs normally go nuts for it) but this time there were none. Weather may have been too dry and they may be underground waiting it out?
So first test was inconclusive. I suspect that they do not like it as much as real beer.
We just have to improve the process. (With your help)

Here are pics of the scum on top on about august 13th a few days after a hydrated lime addition.
It still smells quite vinegary at this stage. I thought the acid would combine with the lime.



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    27 Discussions


    3 years ago on Introduction

    I have always had success with burying beer cans for slugs in the past.


    3 years ago on Introduction

    "Alcohol is not an attractant to slugs."


    im not sure what this instuctable is about really. are you turning garbage into beer, or feeding it to slugs the subject name / ingredients confuses me

    3 replies

    I was trying to make cheap beer for the slugs. But they did not seem to go crazy for the flavor. So, instead I let the fermentation go further. (This is what you do sometimes when an experiment goes sideways.) If someone else tries it, with the right secret ingredient, it might work to attract slugs. Slugworth sizzler beer. Perhaps instead of compost tea, weak weed beer will also be good for plant roots? Or weed vinegar? And then you have sterile weeds left over probably with very dead seeds and roots, and free of disease, that you can throw on the compost with no more danger of weed seeds sprouting. Or potentially, you have "retted" weeds where the fibers may be easily extracted. (Possibly for weed fibre plant pots or soil blocks) Here are my first attempts at soil blocks (It needs a lot of work still). I tried the weed firer instead of peat (saves on fuel because peat goes a heck of a long way to reach your plants). Brian


    Reply 5 years ago on Introduction

    Ah, now there's a good idea: weed fibre plant pots! As you say gaiatechnician, it beat trucking in peat from far away, and it is a onsite renewable resource. Cool.


    Reply 5 years ago on Introduction

    Hi finton, I tried it but did not continue. To be honest, I am not much of a gardener and stone mason (My Job) makes me pretty tired at the end of a day. If you want to try something similar, there is a floating waterweed called azolla fern that grows abundantly in lots of places. It dries out quite nicely, (way quicker than duckweed that looks kind of similar). Anyway, I think Azolla fern might make good hanging basket liners. It has a mat of roots under that are about 2 inches long. I have only a little pond so not enough azolla at a time for a hanging basket so I just use it as mulch instead. In good weather azolla can double in 5 days AND it fixes nitrogen from the air! Might be an environmentally friendly way to do hanging baskets! I do lots of half assed experiments to give other people ideas but 99 percent of people like to play it safe and do proven stuff where the results are already known and you are guaranteed a "successful" experiment. Thanks for your interest. Brian

    No,, I have the same tragedy and comedy as everybody else. And I am socially inept so I never fitted in anywhere. Every night I go to sleep hoping to wake up normal with lots of friends. Hasn't happened yet.

    Well...my daughter is an asperger kid, she doesn't have a ton of friends but...I have NEVER met anyone nearly as kind and thoughtful. I am positive your intelligence and introspect will lead to true friends sooner or later.

    PS I do still think I will give your idea a whirl, thanks!

    Thank you. I did not try it last year. It was a strange year. It took longer to set up the pallet garden project than I expected and the pallet garden project just keeps getting bigger and bigger. My flax is dry in a shed and as soon as it warms up, I will dunk a bunch in the water from one of the pallet gardens and see what happens. We had people over today to check the pallet gardens out and I got an incredibly crude version of the "flutter wing" going for Barb and Kief. The flutter wing is a badly shaped stiff flag that causes vibrations and jerking to and fro in the flag rope. We are going to try to use that to and fro movement to pump air or water.


    6 years ago on Introduction

    Thank you for the great info. I really like it when people are honest enough to say that something didn't work, it is helpful, thanks!

    2 replies

    Hello and thanks. Yes, it didn't work as planned but later I used a similar process to "rett" flax for linen in a closed barrel. This year I will try pond retting linen in version 2 of my "pallet garden". I am hopeful that the "smelly water" is processed by the pallet garden almost as quickly as it is produced. I have also tried growing hops but so far without success. I am too mean with watering in summer and the hops don/t seem to like it.

    Sounds so interesting, I hope that it works out well for you. I am in the Master Gardeners program so, I am learning so much about these topics. I really love to hear what others are doing, it makes me want to try new ideas of my own. Thanks again for the info & have a great night :) Mary

    Binary Being

    7 years ago on Introduction

    Maybe instead of sugar/molasses, try using dry malt extract or spent grains from one of your local breweries. I imagine the spent grains would be fermentable and give you that beer taste. Plus, spent grains make for some great compost.


    7 years ago on Step 6

    try brownseed paspallum seeds or any Paspalum type seeds at the top the one i have had the most succes with in brewing oh and good idea too


    8 years ago on Introduction

     I love this idea. I never even thought of a nice alcohol and acid bath to kill off weed seeds... Let alone attracting and drowning pestilent bugs with the same brew. I hope you hit on a formula that works. I may try this if I get as many slugs this year as last.

    4 replies

    Reply 8 years ago on Introduction

    Sorry, those darn slugs still prefer beer made the traditional way.
    I have a few new developments but  no magic ingredients yet.
    Recently, I ground up weeds with a meat or peal grinder, for  another project and there is a lot of juice!
    Hopefully others will join in and we can share ideas.


    Reply 8 years ago on Introduction

    Hey, whats the biggest thing that will that meat grinder will grind? I was thinking of buying one in order to "mulch" some of the twigs in my yard, and i was wondering if it would work.


    Reply 8 years ago on Introduction

    Hmm, some university reports on composting (sorry, no references) spoke of piling up leaves and such, then tilting a power mower above it and lowering the spinning blades onto the pile. Use a bagger mower for this!


    Reply 8 years ago on Introduction

    I have done that myself. Not just with leaves, I used an electric mower to grind up branches (small twiggy ones) too. I do not recommend it. A bit dangerous.
    But I still do it.