Mineralization and the soil food web

High Nitrogen Fertilizer via Bokashi Vermiculture
06 Nov

Most organic growers have used aerobic composting to process raw organic matter, including food scraps, into a useful soil amendment – compost. Composting is a fairly intensive process requiring the ingredients to have the correct C/N ratio in order to heat up yet decompose aerobically. Aerobic composting recycles only about 50% of the carbon in the starting material, losing the rest to the atmosphere as greenhouse gases. Compost piles need to be turned to keep the contents oxygenated and working quickly, plus they require a fair amount of space. And in our experience, they can attract rodents if food scraps are used.

Enter vermiculture and bokashi fermentation as alternatives to composting, especially in small gardens. Both methods are used to rapidly process food waste into a soil amendment. Both have their drawbacks; worms are picky about what they eat and do not eat raw food scraps very quickly, preferring rotten food to fresh. Bokashi fermented scraps should be used fairly quickly, and are wet and unpleasant to handle.

Now enter Bokashi Vermiculture. We put the two processes together to get the best of both worlds. The result is a stable, high nitrogen soil amendment. Simply put, we use bokashi fermentation to process two vegetarian household’s fruit and vegetable kitchen waste, then feed the fermented mess to our worms who seem to thrive on it. The worms rapidly process the bokashi fermentation product into vermicompost. From kitchen to vermicompost takes less than 8 weeks, which means we get more vermicompost in less time. It’s not a new idea, but then again no one else seems to be doing it.

Both bokashi fermentation and vermicomposting conserve nitrogen compared to aerobic composting, and the result is a high nitrogen, stable soil amendment. A handful under transplants in mineralized soil results in great veggies, like the Chinese cabbage in the picture below (pic taken today).

Chinese cabbage-1

There are plenty of places to buy worm bins and bokashi fermenters. We don’t use either of those, but instead put ours together out of inexpensive parts as described below. Ours is not a system for apartment living, but it could be scaled up or down depending on available space and raw organic matter.

Worm setup-1

The Worm Bin

We have a simple 3′ x 5′ worm bin that is built into the side of a hill. The bottom and sides of the bin are cement backer board pieces left over from a bathroom tile project. The cement board does not absorb water and is solid on the bottom, helping keep the worms moist and any burrowing critters out. Anything solid could be used for the floor; we just used what was around. The cover is a plastic tarp with a second acrylic panel cover to help keep the sun from rotting the tarp. Being built into the hill helps to moderate the temperature in the bin – worms do their best between 70 – 80F but they survive from 38F to 95F. This bin has yet to go through a winter, although our coastal California winters are hardly cold. If we lived in a cold climate we might cover the whole thing with a thick layer of straw and let the worms go dormant for the cold season. If we lived in a wet climate we might not build it into a hill, and take more care to keep rain out.

worms at work-1Our worms are red wigglers, a.k.a. compost worms, Eisenia fetida. Our first handful of worms came from a friend, eventually multiplying from just a few to really a lot. Reproduction does not happen overnight though, even though one adult worm can ultimately produce 10 babies a week. It takes 3 – 5 months for a worm to grow from egg to sexual maturity, so there can be a delay if you don’t start with enough worms. Other native decomposers like pillbugs, sowbugs and earwigs live in our bin, as do some extremely healthy looking lizards. In the picture to the right, uneaten bokashi fermented veggies are visible, which is why the worms are there.

We started our worm careers with a more traditional worm bin, the kind with stackable trays. This worked when we were feeding the worms just a few small scraps. The trouble is that most of our scraps are large (outer cabbage leaves, onion peels, carrot tops) and the little trays could not handle them. And although the tray system worked, it did not produce very much vermicompost. We consider our in-ground bin to be a real improvement.

Harvesting the Castings / Feeding the Worms

To harvest worm castings we move the darker, denser material to one side of the bin with a shovel. This allows the vermicompost material to dry out a little and the worms to move back to the center of the pile. After a couple of weeks we sift these castings into a bucket through an old nursery flat (about 1/2″ mesh) to get any undigested large chunks out like mango seeds or avocado seeds. These go back in pile for further work by the worms.

finished worm compost-1The worms are ready to be fed when most of their food in a certain area has turned into dark castings. We shovel out the darker castings and worms leaving a layer of worms and castings at the bottom, then dump in up to 5 gallons of fermented bokashi, then cover the raw bokashi entirely with dark castings and worms. If there are not enough dark castings to cover the worms with, they are not ready to be fed. If dead leaves or other decaying plant material is available, it could be layered in with the bokashi.

At the same time we are feeding, we “fluff up” the active feeding sections of the pile by gently turning it with a shovel. The idea is to make sure that there are no large sections of undigested bokashi. Even though the bokashi ferment is anaerobic, the worms like to eat aerobicly digested food. It does not take long to convert the bokashi to worm food – contact with a little air will do it. Be forewarned; if you are feeding straight bokashi, this process is not completely smell free! The addition of dead leaves or partially decomposed regular compost at bokashi feeding time will make the “fluff” process more pleasant.

The Bokashi Fermentation Setup

bucket o bokashi fermenting-1
There are many websites and stores now that sell bokashi fermentation supplies; we even saw a bokashi fermenter for sale at Whole Foods. These systems may work very well, but we made our own, including our initial batch of EM1 starter microbes.

Traditional bokashi composting is an anaerobic process using EM1 microbes to rapidly ferment raw organic matter (more about the microbes later). The raw organic matter, in our case kitchen scraps, is mixed with EM1 inoculated roughage, in our case wheat bran, and pushed down to remove all air (more about the bran later). The resulting mix is fermented in a sealed container for several weeks at room temperature.

The picture at right shows a brewing bucket with it’s inner plastic wrap seal off. We use a 5 gallon bucket with a sealable lid and cover the bokashi with a layer of thick plastic wrap before putting the lid on. Note that 5 gallons of solid food scraps and bran is heavy – it can weigh up to 40 pounds. It is possible to find smaller buckets or not fill them all the way up to reduce the weight.

Bokashi needs anaerobic conditions (no oxygen) and a little air can cause it to turn black, go bad and really stink. Properly fermented bokashi looks like sauerkraut, with all the original bits still identifiable, and has a vinegary smell that is no worse than sauerkraut. Commercial bokashi buckets have a drain at the bottom to remove liquid. We haven’t done that on ours; we just use solid buckets, and the bran helps to soak up any extra moisture.

We keep up to 4 buckets brewing while 2 buckets are being filled with new scraps. It takes about 2 weeks for us to fill a bucket, then the bokashi scraps ferment in the bucket for another 2 – 4 weeks, depending on whether the worms are ready to be fed or not. The bokashi bucket being filled is kept outside (the garage would be another candidate spot) and we keep a separate container in the kitchen to accumulate scraps. We also keep a container of bokashi bran to add to the kitchen scrap container. It helps to keep odors down in the kitchen. When we put scraps in the kitchen container, we add a little bran.

Bokashi serum is used to inoculate bokashi bran, which is used to inoculate the kitchen scraps for the bokashi fermentation.

Making Bokashi Serum

There are plenty of good suppliers of EM1(TM) microbes, such as TeraGanix, but to start with I made my own serum from scratch. I got the recipe from this website.
Week 1…
Assemble these ingredients:

  • 1/4 cup rice
  • 1 cup water
  • Quart glass jar with lid

Put the rice and water in the jar and shake vigorously until the water is white and cloudy.
Strain off the rice.
Leave the water in the jar with the lid on loosely
Leave in a dark cool place for 5 – 7 days

Week 2…
Assemble these ingredients

  • A little less than 1 cup of the water, strained
  • 1/2 gallon (8 cups) milk
  • 1 gallon wide mouth jar or container with lid

Mix the water and milk in the jar.
Leave the lid on loosely, !very important!, it can explode otherwise
Leave in a cool dark place for 5-7 days

Week 3…
Assemble these ingredients

  • 1 tsp blackstrap molasses
  • Smaller jars to store the serum in, ~1.5 quarts

The milk should have separated into a curd on top and a clear yellow liquid below.
A little white mold is okay on the curd but black mold is not okay.
Remove the curd – you can feed it to animals.
Strain out the yellow liquid — this is the serum.
Dissolve the molasses in the serum.
The serum can be stored in the refrigerator for up to a year.

The serum has other uses as a foliar spray or soil drench. More on this in a future post…

We don’t know if this recipe results in the same mix of microbes as EM1(TM) – we assume it does not. However we’ve tried both, and they both seem to work fine for making bokashi bran.

Making Bokashi Bran

We buy wheat bran in a 50 lb. sack for about $20 at our local feed store. Other people use newspaper or sawdust instead of bran but we haven’t tried that yet.
Week 1…
Assemble these ingredients

  • 10 lbs bran
  • 2/3 C bokashi serum or EM1(TM)
  • 2/3 C blackstrap molasses
  • 20 C water, preferably de-chlorinated
  • Large container to mix in
  • At least 2.5 gallon container with airtight lid to “cook” in (we use a 3 gallon pail with gamma lid)
  • plastic wrap to fit over the bran in the “cook” container

This is about twice the water/serum/molasses recommended in other recipes on the web. Perhaps the wheat bran we can buy is extra dry? You may want to start with half the water, serum and molasses and see how moist your bran mix is before adding more.
Most recipes call for the use of de-chlorinated water (or well water or rain water) because chlorine can kill the microbes you’re trying to propogate. We’ve had to use chlorinated water at times and the process still worked. We now have a de-chlorinating filter on a hose bib, so we use water from the filter.
Mix the blackstrap molasses in a little hot water to dissolve it. Dilute with cold water or let it cool to less than 110F (it will feel just warm on the inside of your wrist). The serum microbes will be killed by temperatures over 110F.
Mix the serum, cooled dissolved molasses and water together. Add to the bran while stirring with your hand.
You’ve added enough liquid when all the bran is moist and a handful just sticks together when squeezed.
Put the bran in the sealable container, pushing it down to remove all air.
Cover the top of the bran with plastic wrap to keep air out.
Seal the lid.
Store in a cool place for 2-3 weeks

bran drying-1Week 3…
Assemble these ingredients

  • tarp to dry the bran on
  • container to store the dry bran in

When you open the lid of your inoculated bran, it should have a vinegar like smell. A bit of white mold is okay.
We dry our bran on a tarp outside, turning it several times a day to get all the parts dry. It takes 2-3 days drying time, even in our California sun. The picture at right shows 10 lbs of bran drying on a 4′ x 6′ tarp. If it is not entirely dry when you put it away it can grow mold, so it’s best to get it thoroughly dry.

Bokashi Vermiculture has been working well for us. We hope it will for you too!

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02 Nov

Getting minerals to the right place at the right time is the subject of this article: How Minerals Move in the Soil

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Fiesta Broccoli
07 Dec

This is the result of an unintended test.  Both plants were grown in mineralized soil (but without much N added) which had just yielded a very nice crop of tomatoes. The one on the left received feathermeal at about a 200 lbs/ac N rate, a dusting of gypsum for sulfur, and borax at a 2 lbs/ac Boron rate.  The one on the right, grown just 6 feet away, didn’t receive any of these amendments between crops, as there was still a tomato plant growing there.  I think this illustrates two points; first that proper mineralization can produce outstanding heads of broccoli.  Second, that all the minerals need to be in place for this sort of result.  Everything else can be in the soil, but a good dose of nitrogen with a bit of sulfur and boron can make a huge difference. My guess is that without all the other good gardening practices like composting, expert watering, mulching, and weeding neither plant would have succeeded. Big little brocolli

This is the largest head of Brocolli I have ever grown. These seeds are from Fedco seeds in Maine.  We bought the seeds because it produces unprecedented side shoots, so the whole story may not yet be told.

The description is here: http://www.fedcoseeds.com/seeds/search.php?listname=Broccoli&cookies=no&item=3313&index=5

You can see how mineralization helps cheer up the gardener…

Big brocolli

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31 Aug

Isn’t the addition of compost and organic matter enough to grow a great garden?

Unfortunately this is a myth.  We were compost gardeners for years, well, decades actually.  While we were able to improve the tilth and organic matter content of our soil, we often had crop failures or “bad years” or bug and disease problems.  Since we eat mainly from our garden year round, we really notice when our gardens lacks something.  It was not until we began a system of soil mineral balancing that our garden really began to flourish. 

Compost and organic matter can only add a few of the elements plants need and only certain proportions.  By balancing the soil minerals, the compost can do what it does best – create a soil life that is able to break down the minerals and make them available to the plants.   

A thriving soil life is essential for a good organic garden, but it must be backed up by the minerals plants need in the proportions that they need them.

Is Soil Mineralization “Organic”?

Yes. The mineral amendments we recommend are all on the OMRI (Organic Materials Review Institute) list of materials approved for certified organic production.

Is Soil Mineralization sustainable?

Industrial agriculture is probably the least sustainable of all life-critical systems, relying on large inputs of oil, industrial chemicals, and government subsidies while mining the world’s topsoil and sending fertility accumulated over eons down the river. On the other end of the scale, permaculture is touted to be sustainable, requiring a minimum of inputs, but in fact has not had the test of time or pressure to produce that full scale farming has. Plants need certain minerals to be available in certain quantities in order to grow to their fullest potential and so mineralization, or re-mineralization (of worn-out soil) is necessary in nearly all places where land is available to be used for small scale growing. With proper recycling of plant materials, and proper treatment of the soil biology, a garden can produce for years with minimal inputs. It does, however, take mined or manufactured minerals to get it to the point where it can be productive and sustainable.

Is Soil Mineralization related to permaculture?

Permaculture or permanent agriculture is a system devised to maintain and improve productivity of an agricultural system, with minimal inputs from outside the system. However, often times a system may not contain the elements needed for optimum plant health, in the right proportions. And, these elements change with time, due to soil leaching from rain or irrigation, even if all crop residue and manures are recycled back into the system. Transmutation (creation of one element from another, such as creation of gold from lead) does not occur in the garden! While a permaculture system may lessen the need for the addition of mineral soil amendments, it does not lessen the need to test for soil mineral balance and adjust as necessary.

Does this mean I have to do math?

Thank goodness, no!  Given your soil test results and the area you need to amend, we recommend the weight of the amendments you will need.  We’ve done the math for you!


What time of year should I test my soil?

Ideally you should test at the same time every year. That is, unless you want some data at other times of the year. Generally, nutrient levels will be lowest in the fall (on sandy soils this is especially noticeable as they don’t hold many nutrients), after the garden has converted nutrients into food. Sodium and EC levels will be at their highest if it has been dry. Just as rain will carry salts lower into the soil, transpiration and
evaporation will bring dissolved salts to the surface.

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05 Mar
There is quite a large philosophical gap between compost gardening and mineralization.
The former assumes that the earth is bountiful, and the soil in the garden is perfect,
it just needs organic matter to bring out  perfection.  This is quite attractive.
All around us is evidence that  what humankind touches, is diminished.
At least in the garden, one can rest in inherent perfection.

Mineralization has a much larger role for humankind (as does permaculture).
It recognizes that not all soils are capable of growing vegetables in their native state.
The gardener's role is linked to distributing the earth's abundant resources
for the benefit of the plants  and the planet.
There is some overhead involved in adopting this view.
Minerals are mined.
There are good mining practices, and there are bad mining practices,
and we needn't support the bad practices.

Today you revealed to me the idea of perfection, or of the "Ideal Soil",
with it's attendant cation imbalances or balances is just an idea.
Before, I felt like our garden was somehow deficient in not having achieved this balance.
That it could somehow be better.
That I needed to manipulate it's balance before it was perfect.
I guess it was you saying something like,
"If you have a lot of calcium in your soil, why not accept it?",
that turned my head around, back to a native state of rest and equanimity.
Yes, I have found out some things about my soil.
I know it better now.  I have added what I can.
The plants are going to be much more healthy now.
I have brought to them what they could not find for themselves.

I will no longer feel deficient about excesses.  The soil is what it is.
I will add no more of what it already has.
I will slowly meter out sulfur, a great addition for taste and health,
and over a long time,
I will possibly establish a trend tending toward improvement.
Meanwhile, this year, my soil is itself, and full of great abundance.

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