Micro-Compost

This post describes an experiment in composting that ultimately led me to create a worm composter, which is where I'm currently at as far as this ongoing experiment is concerned. This doesn't mean that micro-compos are a bad idea. They worked well and made us self sufficient in terms of fresh earth for our plants.

However, I suspect that worm composters are more efficient and more convenient. I've therefore decided to continue my experiment in that direction. But for anyone interested in micro-composting, here's what we did.

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My wife and I have a balcony with twenty or so potted plants. To keep these plant with nutrients, we add so called "plant food" to their water every now and again. However, we've recently come across a better way to keep our plants healthy. Instead of giving our plants artificial nutrients, we've put tiny composters into the flower pots.

Micro-compost

These are 1 litre plastic bins that we've cut into to allow for air circulation and direct contact with the earth. Holes are cut along the top for air supply, and a hole is cut into the bottom.

Micro-composter cut from plastic bin

Once properly placed into the soil, so that the air vents are above ground, kitchen refuse can be put into them. A convenient way to do this is to keep a small bin in the kitchen where easily compostable refuse is put. This refuse must be cut into tiny pieces with scissors or a knife before going into the composters. Apart from that, there's no extra work involved.

Bin with kitchen refuse

Easily composting refuse are anything vegetable, with the exception of seeds. Egg shell, tea leaves and coffee are also good. A healthy compost should have some dry leaves in it as well. This can be collected from the potted plants themselves. A few peanut shell and small twigs can also go into the composters to keep them from getting too wet.

Positive effects on plants

The effectiveness of our composters has been remarkable. Our plants reacted positively from the very start, immediately producing new shoots and denser and healthier foliage.

Fresh shoots

The composters are currently compacting refuse at a rate of about a centimetre or two every day, which translates to a requirement of 4 litre of composters for each person in our household. We have a diet relatively rich in vegetables, so people with a less vegetarian diet will require less while strict vegetarians may need an extra litre per person.

Procedures

Our experience is that healthy compost is best created by filling several bins in parallel so that bugs and bacteria can evolve naturally into the refuse before we move onto the next bins. Our routine is as follows:

1. Ready several bins by picking them up and dumping their content into a bucket together with some regular soil.
2. Leave a little compost in each bin to seed the next lot with bug eggs and bacteria.
3. Fill the bins in descending quantities over the next few days until the first ones are full.
4. Close the full ones, ready new ones as needed, and carry on.

Compost needs air circulation in order to work. This is the reason for the soil added to the bucket where we dump our fresh compost. Without the soil, the compost lumps together into a sticky mess. However, with the added soil, composting continues in the bucket.

Even better than a bucket is a large flower pot with holes in the bottom, put on top of regular soil, so that water drains out into the soil below, and worms and bugs find their way up through the holes.

We're currently experimenting with an arrangement of flower pots stacked on top of each other. The idea is to get the best possible environment for the final part of the composting process. The challenge is to get the right mix of soil, compost and dry leaves for maximum efficiency.

Flower pots for final stage of composting behind a sunflower

As for the micro-composters, it's important to resist the temptation to push refuse into the bins to get as much as possible into them. If pushed into the bins, composting will be retarded due to lack of air, and there will be a smelly sticky mess instead of a nice healthy compost.

When filled correctly, there will be at first a pleasant sweet smell of freshly cut grass coming from the bins. This smell turns gradually towards a smell of damp forest.

Composters and bucket

Every now and again, we take compost from our bucket and spread it out like a "forest floor" for our plants. It's surprising how much can be given to the plants in this way. Compost dissolves naturally into the soil below, so much so that we're able to consume all of it ourselves.

Compost that has been spread out on soil outdoors dries up and becomes odourless over time. At that point it can be scraped off and taken indoors for house plants so that these too can benefit from our production.

We cannot take compost into the house directly from the bins because freshly produced dirt is not as sterile and clean as dirt bought in stores. Fresh compost contains bits of recognizable refuse, and egg shells are mostly intact. Fresh out of the bin, it looks slimy and dirty. There's also a faint unpleasant smell, but that fades within hours.

If spread out while still sticky and slimy, compost forms a dry shell-like dome as it dries. This dome must be crushed by tapping it with a spoon or other suitable instrument so that it crumbles into dust. The dust will subsequently drain into the soil when the plants are watered.

The compost becomes much less sticky and slimy if the bucket or stack of flower pots where the fresh compost is stored is properly mixed in with dirt. The problem also becomes less with more bugs and worms. Two years into this experiment, we have all sorts of bugs, including earth worms. They help speed up the composting process, and we no longer have this problem. 

Compost dumped to free up space

Micro-composts attract fruit flies and other insects, but these don't stray far from the bins. Very few find their way into our apartment, and a few fruit flies fluttering around here and there is not of any great concern to us. It's not like they are all over the place. In fact, one of the charms of this is the great variety of insects that our micro-composts attract. Our balcony is no longer a sterile display of flowers and plants, but a buzzling place of activity. It looks, smells and feels like a proper garden.

Keep in mind that insects are most active when the air is warm. In the cool morning air, fruit flies can hardly fly, so it's a good idea to fill the composters early or late in the evening, and to keep from disturbing them during the hot hours of the day.

Observations

Two years into this project, we've noticed a reduction in fruit flies. Our eco-system is more balanced. Instead of only a few types of insects, we have a large variety, and many of the newcomers appear to be fond of fruit fly larva.

Our initial fear that our apartment might get invaded by bugs has also been laid to rest. We have no more problems with insects entering our apartment these days than we had before we started this experiment.

Contemplating life over a cup of coffee

The positive effect on the plants from the micro-composts was so immediate that I concluded that most of the effect must have been due to the production of CO2 rather than nitrogen from the compost itself. It appears that we've stumbled on a verification of one of NASA's claims. Namely that our planet is greening due to increased CO2 in the atmosphere. Additionally, we can conclude that most composting and gardening is currently done wrong. Composting shouldn't be done in big heaps, separate from the garden, but in small heaps among the plants themselves. When done at this scale, no other fertilizers are needed.

There's also less need of pesticides because micro-composts attract a variety of insects, many of which are predators that eat pests like aphides and caterpillars. The annual invasion of slugs that we've been having every fall have been reduced, most probably due to the composts. However, we've also had fierce pest attacks due to temporarily imbalances, probably introduced into our composts from kitchen refuse. These attacks have been limited in scope. The overall effect of the composts has been positive, but it would be a lie to say that pests are completely gone.

We made no special effort to seed our composts when we started this project. Apart from a little dirt gathered from a local garden, we added nothing to the sterile soil. However, we now have all sots of insects. We even have earth worms. How they got into our compost is a mystery. They weren't there to start with. But half a year into our project, we got a few specimens in one of our pots and they have since spread to all pots and multiplied to a number consistent with what can be expected in a well composted garden.

The earth worms have had the effect of speeding things up, and they produce a more earth-like end product. They eat into the fresh compost left behind by other organism, completing the process of turning refuse into soil. Their effect on the whole process has been remarkable.

Wax plant with bee

It's clear that the micro-composters create a micro-climate and eco-system much to the liking of our plants and insects. Even birds have been attracted to our balcony. While they have no interest in the composters, they do at times scurry through the forest floor in search of beetles and worms. This leaves a mess on on the balcony floor, and can cause damage to the plants.

The solution to this problem is to open the bucket where the final stage of composting is taking place. This is where the majority of worms and bugs live and birds will home in on this. They will eat bugs and leave bird turds instead. The birds are fed without leaving a mess or damaging our plants, and we get compost rich in nutrients.

Our balcony has become an eco-system, with life forms ranging from bacteria and fungus, to plants, insects, and birds. Finding this fascinating, we've involved our son in this and challenged him to make a picture of what's going on. This is what he made with some help from his father:

Eco-system

We'll bring this up again for our son as he grows older, adding details to his picture for deeper understanding.

An ongoing experiment

We started this project in September 2020, and have now seen this through two winters. The first thing we noticed during fall is the disappearance of hoverflies. The diversity of insects go down. As it gets colder, composting slowed down so much that we have to stop filling the composters. However, composting doesn't stop completely. Temperatures where we live don't fall enough for everything to stop, but the composting is taken over almost entirely by bacteria and fungus, the result of which is a more foul smelling product, reminiscent of horse manure rather than fresh dirt. This smell will persist for some time unless dealt with by spraying the compost with water.

This reverses back to normal once spring returned with sun and warm weather. However, to avoid sour smelling compost, it's best to refrain from filling the composters during the cold months. The rule we use for ourselves is that we stop filling the composters once insects disappear, and we don't start filling the composters again before they come back.

Another trick we've employed lately is to dig down in the earth directly below the composters and dump unfinished compost into these holes. This brings healthy black earth up to the surface while at the same time hiding whatever unfinished compost below ground. We do this as part of spring preparations. The effect is visually pleasing, and it solves the problem of messy looking and smelly spring compost. It's also good for the plants because it simulates the activity of burrowing animals, circulating nutrients in the soil and loosening things up for the root systems.

Our compost has had tremendous positive effects on our rose bush and Bougainvillea. They produce large flowers and healthy looking leaves.

Bougainvillea

However, other plants show signs of stress when receiving too much fresh compost. Our Margarita looked confused and its leaves were pale this spring.

Confused Margarita

But it soon recovered when we reduced the amount of compost given to it, and it has since yielded healthy looking flowers. Its leaves are also back to a healthy dark green.

Our abundant production of compost has prompted us to get more pots, and thereby increase the number of plants over which to spread it. With our balcony large enough to fit some decent size bins, we now have even more plants on our balcony.

One of two large bins

Some plants love their soil as rich as possible while others like it less so. The trick is to find the right balance of dirt and compost and the right type of plants. Instead of looking for plants that require little compost, we're now making a point of finding plants that consume large quantities of it.