Tag Archives: rooftop garden


Each different crop will be grown in a wooden palox box of 125×125. With 1m3 (1 cubic meter) of soil we can fill up 4 to 5 boxes with a layer between 12 and 30 cm of bio-soil, mixed with compost or ecoveen (along the needs of the plants). At dewinter groencompost, we ordered in januari 2012: 6 x 1m3 teelaarde + 2 x 1m3 edelcompost + 1 x fijne groencompost + 1 x ecoveen.
In februari 2012 we put a complementary order of: 12 x 1m3 teelaarde (from which 5m3 will be prepared in 10 bigbags of 1/2 m3 for the trees; and 7m3 will serve for the vegetables), 3 x 1m3 fijne groencompost (for adding during the season to the crops growing), 1 x ecoveen (for keeping the water up in times of drought).

ecioveen edelcompost compost
Ecoveen, edelcompost and compost. Average weight goes as follows:
° teelaarde: 800 kg/m³
° teelaarde+: 700 kg/m³
° gewone groencompost: 525 kg/m³
° edelcompost of fijne groencompost: 550 kg/m³
° ecoveen: 230 kg/m³


Gewone groencompost is door zijn iets grovere struktuur het best geschikt voor diepere grondbewerkingen en bij het aanplanten van houtachtigen.
Fijne groencompost is ideaal voor oppervlakig gebruik bij zaaien of planten en als toplaag voor gazon.
Edel compost is een mengsel van fijne groencompost aangerijkt met organische voedingsstoffen en gebruikt men best daar waar opbrengst belangrijk is.
Ecoveen is de ecologische variant voor turf met gemakkelijke waterabsorptie en een goede bewerkbaarheid.
Teelaarde plus is een mengsel van goede tuingrond met fijne groencompost.
Volledige ontleding van de samenstelling van de compostproducten, o.a. zoutgehalte, zuurgehalte, koolstof/stikstof verhouding, voedingselementen, mineralenen metalen:
samenstelling groencompost.
Bemestingsadvies na grondanalyse in commercieel tuincentrum:

For the seedlings we use a special soil mix, enriched with vermiculite (expands, water) or peat (veen) for retaining water and enriched with perlite (volcanic, water, aeration) for a better draining of superfluous rainwater. We experiment with organic soil fertilizers: green fertilizers fixing nitrogen in the soil: phacelia, fenugreek, mustard, buckwheat: Green manure and fertilizer guide.
In terms of soil remediation (if necessary) we want to experiment with mushrooms, and we set up a mycology-lab. More info on soil improvement: hugelkultur, amrut mitti, indian soil fertilizer with cow dung.

Composting: with a little help of our friends

The self sufficient garden is not far away. With a little help from our friends, the insects and micro-organisms we can find in amounts of zillions in the garden compost heap, we can make microbial fuel cells which can power small devices (sensors) for monitoring the gardens.
Microscope registration of the micro organism activity in a rooftop compost heap. The organisms are ± 1 mm long, there are zillions of it in the compost, the surface covered here is ± 5 square mm.
The organisms are extremely active, it would be great to convert their activity into energy to power the technology to monitor the rooftop garden. Cradle to cradle.
This is how to do it: make magazine – bacteria-battery.


Everything should be made as simple as possible, but no simpler. Einstein

December 2011 I made the first designs for the creation of an Urban ArtFarm.
The Urban ArtFarm (2012) is an extension of the existing edible rooftop garden (2009). The 2 intensive rooftopgardens are situated on top of adjacent parking lots and are physically connected. The edible rooftop garden is specialised in mediterrean and medicinal plants, herbs and flowers – all with an important nectar/pollen value. The Urban ArtFarm focuses mostly on fruits and vegetables. Both gardens are set up along the principles of permaculture. They both host several bee colonies, and are very friendly to other pollinating insects and birds. In both gardens we work with recuperation of rainwater and we make our own compost. We will set up alternative energy systems with solarpanels to power the waterpumps. The beehives are monitored with custom-made, low cost technology.
Design for a new 1000m2 rooftop garden in the center of Brussels. On the roof, we will grow fruits and vegetables for the hungry city.

These pictures show a glimpse from the first build-up phase, on the concrete rooftop of ‘parking Dansaert2’ in Brussel’s city center.
blenderserre outlineserre serremaart fruitbomen futurebakken

More and more people are living in the cities. We have to search for new modes of living, new sustainable ways of food production. Therefore we are researching how to make a network of cultivated, intensive city rooftopgardens and grow food for the neighbourhood.
In the Urban ArtFarm project we want to blend nature, culture and technology. We will explore how to set up a middle sized rooftopgarden with recycled materials, and with the help of DIY digital tools we will study the biotic and abiotec elements of the rooftop ecosystem: the growth, blossoming and decay of plants while they are submitted to the natural elements as wind, rain, snow, etc.

more info in the connected opengreens database: http://opengreens.okno.be/garden_timeline.php?id=28


Sustainable gardening: design, construction, operations and maintenance practices that meet the needs of the present without compromising the ability of future generations to meet their own needs. This can be reached by attempting to protect, restore and enhance the ability of landscapes to provide ecosystem services that benefit humans and other organisms.
Checklist: local climate regulation; air and water cleansing; water supply and regulation * erosion and sediment control; hazard mitigation; pollination; habitat functions; waste decomposition and treatment; global climate regulation; human health and well-being benefits; food and renewable non-food products; cultural benefits; …

The OpenGreens project covers different bottom up approaches for designing human environments that have the stability and diversity of natural ecosystems. Integration of urban agriculture, honeybees and their role in urban ecosystems, renewable energy systems, food sovereignty systems, natural building, rainwater harvesting and urban planning along with the economic, political and social policies that make sustainable living possible and practical.

10 principles of permaculture design according to Bill Mollison* relative location: how elements of the design are in relation to other elements. What are the connections between them?
Multiple function: each element of the design should perform at least 3 different functions. (trees⇒ windbreak, food, rooftop insulation, …); multiple sources: not rely of just 1 source of something (water, energy, …); zone: place the elements of the design according to their frequency of use. Also check the control and utilisation of the energies entering/passing through the site (cold winds, summer sun, …); energy cycling: harvest as many nutrients and energy from the garden design; using biological resources: using the natural qualities of things, companianplanting, pest-controlling insects, …; stacking: observations of natural systems as three dimensional systems (7 layers); diversity: a diversity of plants, a social and economical diversity (people, providers, …); edges: productivity in natural environments increases at edges between different ecosystems. Has to be taken into account when designing the garden. (hedges, ponds, beds, …); small scale: keeping a garden intensive and small; …


A forest garden is a garden modelled on a natural woodland. It has 3 layers of vegetation: trees, shrubs and herbaceous plants. In an edible forest garden the tree layer contains fruit and nut trees, the shrub layer soft fruit and nut bushes, and the ground layer perennial vegetables and herbs. The soil is not dug and annual vegetables are not normally included unless they can reproduce by self-seeding.
It is usually a very diverse garden, containing a wide variety of edible plants.
Many gardens contain the same things as a forest garden, but usually each is grown separately, as orchard, soft fruit aerea, vegetable patch and herb bed.
What distinguishes a forest garden is that all are grown together on the same piece of ground, one above the other.
Gardens like this have long been cultivated in many tropical countries, and are still in places as far apart as Central America, Tanzania and the Indian state of Kerala.
There are no hard rules about what a forest garden should be. In fact, every one should be different, tailored to the needs of the individual gardeners and their family, and to the unique environment of each garden.

What is the difference between a forest garden and permaculture?
Permaculture is an approach to food growing -and many other aspects of life- which takes natural ecosystems as its model.
Both learn from natural ecosystems. In case of the forest garden it is much a direct copy: a forest gardens looks like a woodland.
In contrary, permaculture is not modelled on the outward forms of ecosystems, but on the underlying principle which makes them work: a web of beneficial relationships between the different plants and animals, and between them and the rocks, water, soil and climate of their habitiat.
Natural ecosystems can be very productive, and they don’t need all the inputs of fossil fuels and other materials that are needed to support our present-day agriculture, industry and infrastructure, nor they emit any pollution.
Permaculture seeks to create systems which have all the desiderable characteristics of natural ecosystems but which provide for human needs. The key to achieving this is to set up a network of beneficial relationships between the different elements we need in a garden, on a farm or in a whole community.

virtues1 virtues2
the permaculture garden of Gilbert Cardon (fraternité ouvrière, Mouscron)

Forest gardening and permaculture are not the same thing, but there is much that they have in common. Both are about putting components together in an harmonious whole, so both have a strong element of design, and both are firmly rooted in a sense of ecology.
Permaculture covers a much larger field than (only) gardening. It includes farming, forestry, town planning, financial and social structures and much more. A forest garden may be a component in a permaculture design, but it is also more than just a part of permaculture. It is a way of gardening, indeed the basis for a way of living, which arose quite indepentdently: it can be practised by anybody who has access to a little piece of land, and who has the desire to try something that is relatively new and yet as old as life itself.

Why should we grow a forest garden?
The most sustainable way to grow food is the way which is most like the natural vegetation of that area. Let’s list some global benefits of growing a forest garden. The greatest ecological problem we face is climate change caused by the greenhouse effect. Growing new trees is one way to take carbon dioxide out of the atmosphere by turning it back into living wood. There is no reason why many of these desperately needed new trees should not be fruit-trees, planted by the owners of town and suburban gardens – who, at the same time, would gain the bonus of growing nourishing fruit. The ecological benefits of trees do not stop at being a sink for unwanted greenhouse gasses. They also enable the soil to store more water and then to release it slowly, preventing both flood and drought. They protect soil from wind and water erosion.

How a forest garden works.
First the vegetable layer comes into leaf, then the soft fruit and finally the top fruit. By working in layers, the lifespan of the growing season is extended. The whole volume of the soil can be used, without the plants competing with one another for water and nutrients. A forest garden can make much better use of the available resources –both above and below the ground- than a single layer garden.
The three main products of a forest garden are fuits, nuts and leafy vegetables. Often the distinction between vegetables and herbs is not really made. Anything that is edible and green, cultivated or wild, is welcome in the forest garden. We go for diversity! Many of the plants which are suitable for a forest garden are either taken straight from the wild or have only been slightly modified by plant breeding. Wild plants are on an average much higher in protein, vitamins and minerals than conventional vegetables. Most of the produce of a forest garden (fruits, nuts, salads) can be eaten raw.

There is no digging involved in a forest garden. Soil is not an inert mineral substance. It is an intricate blend of mineral, air, water, organic matter and living organisms. Crumb structure is an important element in fertility. The micro-organisms in the soil are the powerhouse of soil fertility. A lot of essential chemical processes are going on in the soil all the time, processes carried out by bacteria, fungi, algae and other micro-organisms.
In a forest garden, mulch plays an important part in weed control. There are not so many weeds in a forest garden anyway, as digging is the main thing encouraging weed seeds to germinate, and also because any plant that is useful in one way or another is welcome in a polyculture. Many wild plants are edible, and deep rooted ones work at bringing mineral nutrients up from the subsoil. Compost is not digged in, but placed on the surface as a mulch.

The diversity of a forest garden helps to keep it free from serious levels of pest infestation, due to the rich mixture of species and varieties within each of the layers.
Where each kind of plant is mixed in among many other kinds it is much more difficult for pests and diseases to build up. In addition to the benefits of general diversity, there may also be specific interactions going on. Some plants provide food for insects which are predators on plant pests. The greater the diversity of plants and the more they are intermingled the healthier the garden.

Make your own backyard ecosystem. It’s about the fascination of being a witness and a participant in the growth and the development of an ecosystem. A forest garden has a longer cycle. As trees, shrubs and perennial vegetables all grow at different rates they all have different lifespans. They spread and shrink in response to age and different seasons. Completed by the wild plants and animals that move into or out the garden as conditions change, a kaleidoscope of changes is unfolding as each year unfolds.

A forest garden is foremost a home garden. But with its combination of tree fruit, bush fruit and vegetables on the same piece of land it provides in the needs of its gardeners. And more, with the yield of a forest garden we can make a direct connection between growers and consumers, as home gardening avoids the costs of packaging and transport and allows for the return of all nutrients in the food by means of composting directly to the soil that grew that food. It is indefinitely sustainable. It is the basis of any truly ecological way of living that where we do things is at least as important as how we do them.

A forest garden does not need a lot of work, but it does need attention. It needs someone to wander through it regularly to see how it is getting on, it needs someone to inhabit it. This can happen without effort if the garden is at the gardeners’ workplace or living place.

Text inspired by Patrick Whitefield (How to make a Forest Garden)