15. Tricks to making a good soil factory

Follows on from: Using charcoal in your soil factory

About the soil.

Use whatever you have on hand.

And a 50:50 mix is often best, although you can do this however you want.

The smaller pieces you have in your bokashi bucket the faster they will transform to soil, as the microbes have more surface area to work with.

By the same logic, it’s worth mixing the soil and bokashi really well when you prepare your soil factory, the more you coat the food scraps with soil, so everything looks more or less brown, the faster the process will go.

But you don’t have to. It’s also ok to have big chunks in your bokashi bucket, and to not mix it at all well. But the process will take longer, so it’s completely up to you and what your timeframe is.

When bokashi turns to soil it is more accurately absorbed up into the surrounding soil. So the type of soil you use in your soil factory will be the type of soil you end up with — only better.

If you use peat-based compost (the type you usually buy in bags from the garden shop) in your soil factory, this is the type of structure you will end up with.

Likewise, if you take clay, or sandy, soil from your garden, this will still be the base in your soil factory. It will be richer, and more alive, obviously, and contain a lot more humus. But it will still feel like peat, or clay, or sand or whatever you started with.

An option here is to mix the types of soils you’re adding to your soil factory to get a structure you would like to have. It’s not necessary, but may be worth thinking about.

Common sense, really, but so is much of what we do in the bokashi world.

A common question is whether it’s ok to use really ”worn-out” soil from potplants, tomatoes that have been grown in pots and buckets, or from a greenhouse.

Everything works.
Even if the soil is full of old roots (typical for ex tomato soil), it’s no problem.

The old roots and plant leftovers will be taken care of by the process, they will eventually become rich, living soil like everything else in the soil factory, and nothing will be wasted.

One thing though that I’m not completely sure about is using soil that has come from tomatoes for growing potatoes in later. Or vice versa. Informal reports seem to indicate this is fine, but until we’re more sure, you might want to be careful.

When is the soil ready?

Well, you can just poke around and have a look — it will be obvious when it’s ready. What you may find is a few straggling bits of food waste, avocado stones are a classic, as are coffee filters, bones and egg shells.

You can just transfer these over to your next soil factory, add them to the garden, or do whatever makes sense for you.

In general, though, it’s better not to poke around in your soil factory any more than necessary. The first couple of times you do a soil factory it’s inevitable — we’ve all done it. You’re really curious about what’s going on and can’t quite believe it’s true. But sure enough, it is. Bokashi is amazing!

But if you can, let the process have its way in peace.

The reason for this is that bokashi is essentially an anaerobic (or non-aerobic) process. Bokashi becomes soil without generating heat, in this way it’s completely unlike traditional composting. Sure, the soil can ”breathe”, that’s why we don’t cover it up, but there’s no oxygen actively introduced to the contents.

Should you stir up the contents of the soil factory, a lot of new oxygen will come in. That starts an oxidation process, which means air is added, and this triggers energy in the bokashi to be converted to heat.

The heat itself may help speed up the process, but it’s done at the cost of energy in the soil; that energy, if it was left where it was, would actually be available to your plants later. So it’s kind of a waste to just let it go like this.

A traditional compost, or even dung heap, works in this way. You have to keep turning the pile to introduce oxygen; that oxygen causes the organic material to oxidize and generate heat; the heat-loving microbes in that type of compost do their work to decompose the organic material and knock out pathogenic bacteria.

Bokashi on the other hand works at low temperatures, there are no heat-loving bacteria, pathogenic bacteria are knocked out by the low pH of the initial process and generating heat is a waste of valuable energy that could otherwise be preserved for future benefit.

So, stir around by all means to satisfy your curiosity, it’s hardly the end of the world, but don’t do it with the idea you’re helping the process along.

Just let your soil factory do it’s thing in peace and quiet, it will all become great soil in due course. Our bokashi and soil microbes know exactly what they’re doing, and left to their own devices will fix it perfectly.

A couple of things that may surprise you.

Sometimes a soil factory with a lot of peat-based compost in does absolutely nothing. The process never gets going, and the bokashi just remains as it was on day one.

We’ve had this a few times in our discussion group and were pretty surprised when it first happened. But the conclusion we reached was that sometimes this type of peat (which comes from a peat moss and is then sterilised) is so totally lacking in soil microbes that it gets fermented along with the bokashi. So instead of doing the work of soil in the soil factory, it actually just becomes an extension of the bokashi itself.

The only solution is to start again, and add some real living soil.

Another thing is that sometimes you’ll get some white mould on the surface of your soil factory. This is completely ok. It’s not ”mould” as such, rather it’s part of the process and related to the yeast microorganisms that are in EM and bokashi.

You can scrape it off using your hands or a trowel, if you wish. Or just leave it as it is.

If you have other colored moulds the reasons are generally different. Check for moisture levels; too wet and you run the risk of getting green, blue and even black moulds developing.

These are not good, and the best thing is to remove any of that type of growth and dispose of it in a safe place away from the garden.

Next up: sends

14. Using charcoal in your soil factory

Follows on from: Make a soil factory

It’s really good to have some form of absorbent material in the bottom of your soil factory.

The absolute best is charcoal. You can use the same charcoal you’d use on the barbecue as long as there is absolutely no chemical additives in it, and that is made from some form of responsibly harvested wood.

Crush it into smaller bits if you can. No briquettes, and no ashes – they’re not good with microbes.

The reason that charcoal is so good in this context is that it absorbs a lot of moisture. It tends to take care of any odor issues. It retains a lot of the bokashi nutrients and microbes that it absorbs, and microbes really enjoy hanging out in charcoal.

When charcoal is charged up with nitrogen (which is what happens when it absorbs bokashi nutrients from your soil factory), it becomes known as biochar.

This is the same as terra preta, something that has become very trendy in recent years for good reason, as the Amazon farmers that invented it centuries ago knew what they were doing. Adding biochar to soil makes it really rich and dark in a long-term way that few other methods can match.

So long story short.

A layer of charcoal in the bottom of your soil factory will take care of any potential drainage issues and become a great additive to your soil in the long term. Easy.

Other options

There are alternatives though, all quite ok.

Newspaper is an easy fix. A couple of newspapers in the bottom of your soil factory will absorb a lot of excess moisture. Shred them if you wish. Egg cartons, toilet paper rolls, corrugated cardboard etc all do the same job.

If you end up with felt-like wads of newspaper when you empty your soil factory you can either bury them in your garden or use them as mulch under berry bushes or around other perennials. The newspaper is soaked in nutrients and microbes and will attract worms from the entire district, it will also prevent weeds from growing up and retain moisture in the soil.

Cover the paper with something like wood chips or bark, leaves or grass clippings to improve its appearance and keep it in place.

If you use sawdust pellets for heating in your home, you can use a few handfuls of these as a base in your soil factory. They absorb a lot of moisture and expand accordingly. No problem having them in your soil later, assuming they are chemical-free.

Absorption pellets used in cat litter products are also a good base, assuming they are made of natural materials and chemical-free.

Clay drainage balls, called leca in Europe, are also good, although they don’t actually absorb moisture.

You don’t always need this absorbent layer in your soil factory, it depends largely on how dry the soil is that you are using. If you are using really dry, depleted soil that you’ve emptied from pot plants etc, you won’t need any further absorption material. The soil will take up any excess moisture from the bokashi.

And actually, a soil factory shouldn’t be allowed to get too dry either.

Microbes work best in a reasonable balanced humidity, not too wet not too dry. More or less the same as you’d have in good growing soil. So if your soil factory seems really dry you may have to water it a bit to get things going.

Another way to maintain the humidity balance in the soil factory is to lay a newspaper or old towel on top. This will stop it drying out too much, or absorb surface moisture if needed. If your soil is a bit damp, the towel will prevent any odor from spreading out into the room — especially important if your soil factory is in the bathroom!

Next up: sods

13. Make a soil factory

Follows on from: Best soil for your pot plants

method three
make a soil factory

A ”soil factory” is something we came up with years ago to describe a place where you make soil using bokashi.

It can be a bucket, a tub, a bag, a planting box, a barrel, whatever you have on hand basically. The thing is that it’s used ONLY for making soil, not for growing things in.

But otherwise, it’s basically the same as any other bokashi process. Mix bokashi with poor soil and wait for the soil to become great again.

You can have a soil factory indoors or outdoors. Or both.

There are benefits to both, and they largely depend on what sort of climate you live in, and what type of gardening you’re doing. Also, which season it is.

You can make a soil factory pretty much in any way you want it. Strong or weak in terms of nutrients — this depends largely on how much bokashi and soil you have on hand, how much space you have, and what you are planning to use the end product for. But 50:50 bokashi and soil is a good mix to start with, you can develop the concept from there.

There are only two basic rules with a soil factory, whether it’s inside or outside. The mix should not become too wet, or too dry. And it needs to be able to breathe — in other words no lid.

The mix should however always be topped off with a layer of soil (of whatever quality), you shouldn’t be able to see the bokashi food scraps at all.

If you think about it, making a soil factory is very like making a hole in the ground and digging down your bokashi. You could say the same about preparing a pot plant tub or other container for planting in; it’s basically the same thing as a hole in the ground with bokashi and soil mixed in.

Let’s get a bit more specific here. Indoors first.

For a soil factory to work indoors you’re going to need a certain amount of heat, ideally room temperature. If you live in a cold climate (like I do) you’ll get this. Our cellars are normally pretty cold and while you can make a soil factory in a cold space it will take forever for the transformation to take place. Fine, though, if you just want to store your bokashi somewhere until the spring.

So 20+ degrees C is ideal. Above 15 degrees you’ll get a slow transformation, below that, nothing much will happen.

Some people have small soil factories in the bathroom, on a heated floor. This probably really annoys the family but it’s a great way to make soil — it can go as fast as two weeks.

You can also recreate this concept in a cellar by using a heated mat. I made one at home by taping weak electric cables on the underside of a big planting tray and placing that on top of a block of styrofoam. Not very fancy, and the styrofoam melted a bit, but it worked and you get the idea. (I also use it for starting up seedlings, so it’s quite a handy thing to have. )

An indoor soil factory needs to be a convenient size to move around if necessary, 10 to 20 liters is often good (bigger than this and you’ll need wheels).

Wider and lower containers are better than higher and narrower, makes it less likely you’ll spill soil and bokashi all over the floor, and easier to poke around and have a look how things are going.

While outdoor soil factories will need drainage, indoor soil factories need to not leak. So no drainage holes. But bokashi can be a bit wet, so you’ll need to think about this. If the mix in your soil factory is wet (probably because the soil itself was wet and unable to absorb moisture from the bokashi), then you will unfortunately have a problem with smell.

This is also part of the reason for using an open bucket/tub/container. It needs to breathe, much as soil breathes in nature. Usually any excess moisture just evaporates from the surface of the soil, but if it is soaking down to the bottom of the tub you may end up with a rancid layer that is less than pleasant.

The best way to counteract this is to start every soil factory with a layer of absorbent material.

Next up: sods

12. Best soil for your pot plants

Follows on from: Use bokashi in your containers and pots

Good soil holds moisture

Watering is usually a problem when you grow in containers, as they just can’t hold the same amount of water as an in-ground bed, and also because containers are usually planted quite densely.

They also tend to dry out quite quickly, especially porous terra-cotta containers, and in a hot climate the soil will get quite hot and dry.

The ”soil”, which is often not more than low-quality peat, often becomes kind of waterproof, whatever you do you can’t get it to absorb moisture.

One of the great things with bokashi is that it adds a huge amount of organic material to whatever soil substrate you’re using: peat, clay, sand. This improves it’s ability to retain moisture for longer. So that when you water your garden it will actually stay watered. Yes!

So your containers will be easily to water and keep moist. That’s good.

But there’s another issue. Containers always have drainage holes, and any water that’s not retained immediately will drain out.

Some have water reservoirs built in, a kind of zone at the bottom of the container that holds excess water under a grid and allows the plant roots to suck it up later, or alternatively the soil itself to suck it up through osmosis.

These types of containers (and you can make them yourself) are great because they cut down the need for watering. But there’s another valuable thing, and that’s to do with nutrients.

Retaining nutrients

It’s such a pity to have a lot of bokashi in your soil, to have a soil really full of nutrients, and then — because it’s raining a lot, or the containers are being watered a lot — to watch a lot of those nutrients wash away through the drainage holes in the pots.

Often to no avail because there is no soil underneath to absorb them, so the nutrients are just lost in the gravel or on the asphalt.

I tend to grow a lot of stuff in big plastic tubs that I’ve adapted to have a decent- size water reservoir. (You can have long discussions about the merits and otherwise of growing vegetables in plastic that may or may not be food quality, but lets leave those for another day).

These big black tubs, they come from the cement business, are usually 60 to 100 liters. I use them in and around my greenhouse, on my deck for growing snail-free salad and herbs, and around the house to just brighten up some ugly corners with flowers.

These tubs have no holes, obviously, but rather than drilling drainage holes in the bottom, I just drill one biggish hole on the side of each tub some 10 cm up on the side. I then fill the tub with drainage material (clay ”leca” balls in my case) up to this level.

This will form the water reservoir; any runoff from the soil will be stored in this area, amongst the drainage material, and only if it reaches the height of the hole will it run out.

That way I’m protected during rainy periods, my plants won’t drown, but in any normal circumstances they will always have access to nutrient- rich water from the reservoir.

The rest of these tubs I just fill with soil and bokashi as described above. I tend not to empty them, ever, but each spring I dig down some fresh bokashi into the existing soil to freshen them up.

This method is so extremely simple, using bokashi to fill buckets, tubs and planters for a container garden, but it is incredibly effective.

And rewarding, because the flowers and herbs you grow on your terrace and balcony, or in your urban garden, will be so much healthier and stronger than you’re used to.

And they may even have worms!

Next up: Make a soil factory

11. Use bokashi in your containers and pots

Follows on from: Ways of using bokashi in the garden

method two
Use your bokashi to create soil in containers, planters and tubs

You can grow a whole garden without having any real in-ground soil.

The results can be fabulous. And the options are endless when you can start a garden on a street corner, a back yard, a deck, some paving, a bit of asphalt or gravel, or a terrace.

Plants need water, and often container gardening needs a little more focus on that. But more than anything they need good soil. And the so-called soil you buy at the garden shop just doesn’t do the work it needs to do.

Garden shop soil, or potting mix, is often based on a form of compost. In worst case (and nearly all Swedish ”soil” falls into this category), it’s based on harvested peat that really should have been left in the ground.

While these type of substrates often work well for a season, or half a season, they tend to compact and become dry and hard to water after a while.

The nutrients that they were pumped with (usually in chemical form although occasionally they use animal manure) are depleted. They never had any micr- life in them. And as a result, plants struggle.

The solution is to renovate these soil substrates by mixing them with bokashi. You can do this before or after a growing season; the important thing is never to throw away soil because it has become useless.

It can always be fixed up! And should be.

One of the easiest ways to fix this soil is to tip it all out of its sacks, bags and planting containers at the end of the season. Or prior to the beginning of the next.

You can mix it with bokashi in a wheelbarrow or on a tarp and fill your containers from there. Or you can layer the tired soil and bokashi directly into the containers, buckets, planters you’ll be using for the next season.

One third bokashi and two-thirds soil is a good rule of thumb. A little stronger, up to 50 per cent, if you are going to plant intensely or plant bigger, or more demanding plants.

Making bokashi soil in a container

A good method is to put a bottom layer of drainage material into your planter; gravel, stones, broken ceramics, leca balls if you have them in your country. Then a layer of soil; it makes no difference how poor it is.

Then your layer of bokashi, straight from the bucket where it’s been fermenting. Another layer of poor soil. And finally a nice, attractive layer of fresh dark soil that will look good on the surface.

You may wish to prepare a whole bunch of these containers ahead of time, ready for the coming season or for when your seedlings are ready to go out.

In this case, it’s no problem if it’s cold and the bokashi will take time to turn to soil. You can line them up along a terrace or in the greenhouse and when the time comes to plant they will be ready there waiting for you.

Or you may just want to prepare one or two tubs or planters ready for your summer flowers.

Use the same method, but wait a couple of weeks before putting in any plants with roots that will reach into the fresh bokashi. The reason for this is that newly fermented bokashi has a very low pH, it’s quite acidic, and needs a couple of weeks to stabilize with a normal pH that your plants will like.

On the other hand, if your plants are small and your container is big, you can probably plant directly.

If you think it will take a couple of weeks for their roots to reach down into the bokashi zone there is no risk. The process can sort itself out during the time your small plants are growing. And when their roots do reach the bokashi supply they will get a pleasant surprise, and no doubt start growing fabulously!

This method is good if your plants are all similar, and their roots are all going to end up at about the same depth.

Sometimes, though, when you do a summer planting of different types of flowers, they will all need different things at different times.

What I do then is mix the soil and the bokashi in the wheelbarrow. The same mix: one-third bokashi, two-thirds soil, but just more homogenous. Then I fill the planter and top it off with some ”nice” soil.

In this case you really need to wait before planting the container though, as the roots will get in contact with the bokashi immediately if you were to plant them straight away. Wait two weeks, and then even if you can still see traces of bokashi, it’s ok to plant your flowers.

Another thing with container gardens of this type is that they will probably attract worms. Sometimes it’s impossible to understand where they come from; in the harshest of urban environments they can just turn up sometimes. And next thing you know there’s a worm colony in your container garden.

It’s just to be happy; worms are wonderful. And as long as they’re happy they will stay.

Next up: Best soil for your pot plants

10. Ways of using bokashi in the garden

Follows on from: Digging down other stuff into your bokashi hole

The basic concept of digging a hole, filling it with bokashi, and covering it over, then planting, is really all you need to know.

Everything else is a variation on that theme.

One of the really fun things with bokashi is that it’s quite creative. There are any number of ways you can use it. As long as it works for you, then it’s ok.

There are no hard and fast rules once you follow the absolute basics, and a lot of scope for experimentation.

We’ve tested a lot of things over the years. I’ve lost track of the number of ”brainwaves” I’ve got at the kitchen table, or while I’ve been out fixing things in the garden.

”Oh, I’ve just got to try that!”, and sure enough five minutes later there’s a trial project underway.

Some of these ideas have been pretty silly, and you’re not going to hear about them. But surprisingly many have worked, and gone on to become institutions in the bokashi world.

The more-or-less established concept of the ”soil factory” was one of those kitchen table inventions.

I was struggling to explain what I meant, this weird idea of making soil in a box, in some sort of systematic and repetitive manner. So the soil factory became a thing, initially at home, then on the blog, and ultimately out in the gardening community.

We have them now, we gardeners, indoors and outdoors; small, medium and large; in barrels, buckets, tubs and containers.

It’s cool!

So, here are some of the ideas that work, that have been tried and tested by many of us.

Use those that make sense to you, adapt them to whatever you have lying around at home, and to the kind of home and garden you have. To the kind of climate you have. To the season, and to your needs for fertilizing, pre-planting, building soil and to making the logistics of your daily life as easy as possible.

method one.
Dig your bokashi straight into the soil.

This will always be the best option. Not only because it’s the least work, but because it’s the best way to look after the nutrients, energy and microbes in your bokashi.

Once you’ve dug down the contents of your bucket, they will never be disturbed again. You’ll get the benefits of the outside world (worms, soil microbes, rain) and together they will create the best possible soil ready for your plants to grow in. No reason to fiddle with nature!

But this is not always practical. Sometimes you have stuff growing on every square centimeter of your garden and it’s not realistic to dig down a single bucket, anywhere.

For those of us living in arctic climates, bokashi can be impossible to dig down for many months of the year, the ground is frozen.

If you’re an urban gardener, or grow in containers or raised beds, the concept of digging straight down into the soil can be translated to filling beds, containers and planters with layers of bokashi and soil.

You’re still creating a reasonably undisturbed environment for planting your flowers and vegetables, and using bokashi in the smartest way possible.

But in general, the no-dig principle applies with bokashi. Once you’ve got it down into your soil, just leave it.

Worms, microbes and any number of other tiny creatures organize things just the way they like it; there’s no reason to mess it up unnecessarily for them.

Next up: Use your bokashi to create soil in containers, planters and tubs

09. Digging down other stuff into your bokashi hole

Follows on from: How much bokashi should you dig down?

Bokashi is the ideal way to deal with kitchen compost, but what about all the other waste that comes out of a garden? The stuff that usually forms the base of your garden compost.

Up to you, there’s no reason why you can’t do on having a traditional compost pile in some corner of the garden.

But here’s a few other options.

Fresh green garden waste makes great mulch, you can use it directly in your beds.

The most valuable of all is grass clippings, these are so full of nitrogen and it’s nitrogen of the quick-release kind, so this means when you put fresh grass clippings round your plants, the plants will get fed more or less immediately. As the grass clippings turn brown and the layer becomes thinner, the goodness sinks down into the soil and feeds the plants.

The worms will help, pulling what they can down into the soil and feeding up on it.

The clippings will also help shield the soil, so that it loses less moisture to evaporation and stays cool in the summer. This will keep the worms and microbes closer up to the surface, doing their work, rather than diving for cover underground. We want them working, so whatever we can do to keep them employed the better.

As the clippings sink together you can top them up with more; use whatever you have available and make sure you get hold of your neighbor’s too if they’re not using them.

Be a bit careful with tiny seedlings, they might get choked on too much grass clippings, but you can thicken up the layer around them as they grow.

Another issue may be snails, if you have a problem with them in your garden. Let’s leave that for another section.

Other green garden clippings work much the same way.

Harvest scraps such as the extra leaves and stalks from vegetables you’re picking can just be left right where they are on the soil, around the plants. Much less work, and the goodness in them will be transferred directly to the remaining plants and surrounding soil.

Tear them up a bit, especially the bigger ones such as rhubarb leaves — this makes it easier for the worms and microbes to do their work and probably looks a little bit neater.

If you need to clear the area for whatever reason, scrape together the mulch and use it elsewhere.

Another great way of composting green waste directly is to dig it down at the same time as you dig down your bokashi. Let’s say you’re digging a trench for beans: dig the trench, layer in the green mulch, then cover over with the contents of the bokashi bin.

The green materials will add nutrients, structure and volume; the bokashi microbes will migrate to the new material and, while it won’t be a fermentation as such, you’ll get much more impact from the bokashi you’re digging down.

For very little work.

Bigger green waste, such as stalks from sunflowers and Jerusalem artichokes, can also be dug down directly.

You may want to collect them up in a pile somewhere (I usually do this on a bed that’s not currently in use so that nutrients from leaves etc can migrate down into the valuable soil in the bed) and use them when you’re preparing a new bed or remaking an old one.

Chop them up if you want, or just lay them down straight in the base of your ”project bed”. Top with more harvest or garden waste and as much bokashi as you can spare, this will activate the process. Mix with soil, cover and plant. It will all become great soil in the end, and nothing will have been wasted.

Besides, it’s a lot less work than moving things from pile to pile.

Brown waste can be used in a similar way, but the nutrients work a little differently. Green waste has a lot of nitrogen, gives the plants an immediate boost as well as providing a good mulch layer.

Brown waste, which includes autumn leaves, wood and bark chips, stalks and stems that have hardened, are all great sources of carbon.

Because they don’t have a lot of nitrogen they don’t feed the plant directly, but they do feed the soil by adding carbon, stucture, and a good meal for many of the micro creatures in the soil.

So add them where you can, in a way that works for you.

Sometimes, when I’m making a new raised bed, I start off with a few branches and a pile of wood chips, as well as any other bits and pieces I have lying around. I know that this material will sink together over the first year or two, so the bed will have to be topped up to the level I want.

This type of brown material tends to absorb nitrogen from the surrounding soil, so I also tend to overcompensate with nitrogen-rich materials when I’m filling the box.

An extra good dose of bokashi, or a lot of green materials, or maybe some horse manure if I have it available. Sometimes it may be enough with a couple of bottles of bokashi liquid, or a watering can or two of nettle or urine fertilizer. Whatever is available, basically.

But this type of woody, brown stuff makes a great base for a garden bed. It also makes great surface mulch.

The only think I’m a bit careful with is raspberry and blackberry stalks — they are so terribly invasive. Even when you think they’re dead, and you’ve buried them too deep to cause trouble, they still go on growing.

And once you’ve got them in your bed you’re in deep trouble. I usually dry them in the sun for a couple of months first. But I do have some trouble spots in my garden where I’ve learnt the hard way.

To my eternal regret…

Next up: Ways of using bokashi in the garden

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