Tag Archives: rooftop garden



Seed saving is plants moving through time and space. I am drying following herbs and flowers as basic ingredients for herbalist preparations: macerates, creams, tinctures, oils, sirops, …
Rosmarinus officinalis – rosemary; Thymus vulgaris – thyme; Eucalyptus gunnii – eucalyptus; Agastache foeniculum – agastache; Salvia officinalis – sage; Origanum vulgare – oregano; Mentha piperita – peppermint; Hyssopus officinalis – hysop; Satureja montana – savory; Matricaria chamomilla – chamomile; Viola tricolor – heartsease; Continue reading



Short chain distribution from the rooftop Farm’s harvest, mainly to neighbors and friends: Otber, Toestand project Vilvoorde, Romuald + family, Lucia en Johannes, Radha, Alexandra, Luc, Jan & Christel, harvest dinner Cubans, harvest dinner Axel&Marie, Luc, Jan&Christel, Clémentine, Joeri, Zahra, Jonas Gruzka, Billy, Franziska & Sam, Nathalie Hunter, Daniele Sambo, Radek, Macek, Burning Ice, Eggevoort Water Project (citymined), Nicolas, Katia from den Hague, Els, Billy and Fabrice, Louis Schreel BBQ 10 people, Joannes Vandermeulen, mama, Miet, Els Lingier, Betty Schiel, Luc Steels, … Continue reading



Or how to spend your free time in summer. The pantry is loaden with the abundance of summer harvest. We are cooking, steaming, drying, freezing, potting and processing roots, fruits and vegetables in all different ways. We dry leaves for tea (fennel/leaves, vanille, liquorice, fennelseeds, bitter orange peel) and for making medicinal recipes.
further reading: how to preserve tomatoes? Preservation of vegetables in oil and vinegar: It is now a relatively common practice to bottle vegetables and herbs and spices in either oil, vinegar or a mixture of both. Continue reading

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We collect the rainwater from the surrounding rooftops to foresee in the water supply of the rooftopgarden. As the rooftopgarden has a limited amount of soil, and because the elements (wind and sun) are stronger high on the rooftops, the soil needs more water than in a ‘natural’ situation. The watermanagement becomes thus very important. It takes up to two hours to water the complete garden manually, with the hose. To save time, we decide to install an automatic wateringsystem, consisting of a microdrip system that is connected to the watertanks and that is controlled by humidity sensors.
To develop and automate the wateringsystem in the rooftop garden, we plan a workshop with Jonas Z. to look into the possibilities of his OSMOGAS concept in real physical situations. OSMOGAS (open source modular gardening systems) researches easy deployable modular systems for gardens. It consists of three main groups of modules. The first group are evironmental measurement sensors (air pollution, humidity, temperature, UV, wind, pH, …), the second group focuses on the ‘outputs’ (digitally controlled switches for water pumps, lights, fog-generators, …) and the third group develops stand-alone systems or the connections to bigger systems (computers, servers). The project focuses on simplicity, DIY and user friendlyness while designing and producing the modules. All code is available online, as well as the schemes and drawings for DIY, and manuals are edited in an understandable language.

osmogas control panel DIY humidity sensors box with arduino
Osmogas automatic watering system: parts. Relay box – controlled via Arduino or compatible board, can handle 2200W. osmogas and osmogas rooftop garden.

Measuring moisture can be done very cheaply and easily if done with care. The principle is based on the water conductivity in soil – the more water in soil (more moisture), the more conductive it gets. We measure the conductivity by simply trying to push current trough the soil and measuring how much get trough. This is done by pair of wires or nails at circa 2 cm distance. To connect such sensors, we work as with other resistance based sensors – to one pin we provide 5V and from other pin we get the output. It is required to use a pull down resistor as well. This means, we connect a smaller resistor from the output of the sensor to the ground.
Sunlight, temperature, water drainage and fertilizer control: another garden automation system is called GardenBot. It uses open source hardware (Arduino) to monitor humidity, temperature and soil conditions. The key modules for the system are soil moisture sensor, soil temperature sensor, light level and water value. Each of these modules can be built separately and integrated into GardenBot. Once GardenBot is alive, it can send data to a computer so that the information is plotted on a chart and updated every 15 minutes. gardenbot

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8 x 1000 liter + 4 x 250 liter wateropslag (van het aanpalende dak en recuperatie van het serredak) wordt opgeslagen in de klassieke witte recuperatie watertonnen. Doordat de tonnen wit en semi-transparant zijn, ontstaat er algengroei. Iemand raadde mij aan om een UV filter te plaatsen. Is dit de oplossing? Blijkbaar niet, vwant het water moet dan continu door de filter heenstromen, anders komt de algengroei weer. Eventueel de tonnen zwart verven, of inpakken met opaque plastic. Een filter plaatsen nadat het water door de pomp gegaan is.
Ik heb de tonnen na enkele maanden ingepakt met anti-worteldoek zodat ze afgeschermd zijn van het licht ter voorkoming van draadalgen vorming. Grote filter geplaatst na kraan na pomp (01/10/2012). Toevoer aangebracht in de serre. Vandaaruit 4 circuits gelegd, met op elk circuit nog eens een extra filter en druk(bar)controle: 1 voor de serre en 3 buiten. Microdrip systeem verder uitgewerkt met oranje (2 l/uur) en zwarte (4 l/uur) nozzles.

Green roofs water management : the virtues of moss
A moss garden is a micro ecology. It tells a lot about the bigger ecological system it is part of. It acts in a way as a bio indicator. Moss is very resilient. How expansible is this resilience in city context?
Moss is also a source of inspiration for designing new materials. Bio mimicry. More info on moss in the rroftop garden: moss garden, Tortula muralis and Tortula muralis research.

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moss on the roofs of the valldaura project

While green roofing is an accepted stormwater control technology, little is known about the quality of the roof runoff. In Phase I of this research, several green roof media (formed from commonly-used expanded minerals, stormwater filter media, and organic matter) were evaluated for their abilities to retain the pollutants from a synthetic acid rain. The samples were analyzed for metals, nutrients, and pH. The hypothesis was that a mixed media that is “better” at pollutant removal and permanent retention could be created based on these laboratory testing results. A media composed of expanded shale, granular activated carbon, and sphagnum peat moss was the most effective.

Optimizing the Water Quality of Rooftop Runoff



The purpose is to gather data on the effects of urban air pollution on urban gardening- and farming crops. Soil can be analyzed and heavy metals in soils can be treated by bioremediation (mushrooms, green manure, nitrogen fixers), but on the effects of city air pollution on crops there is not a lot of information available. How do car exhaust, road dust and acid rain affect the different crops? Is the environmental pollution affect different for leaves, flowers, roots or fruits? Are nuts, fruits and berries less exposed to the urban pollution risks than leaf crops as spinach, or as root crops which do take up and accumulate metals from dust particle deposits in the soil? How might we intelligently assess risk and proceed with a program of harm reduction, and modify urban garden design strategies around these known risks?
Pollution is definitely a concern for city farmers, but luckily, the pollutants of greatest concern are heavy metals, such as lead, and automotive break pad particulates. Both are denser than air, so vegetables grown on a rooftop high above the roadways are protected from these contaminants. The limited lifespan of plants mean they absorb significantly less contamination than our lungs do.

Field research could be:
– how long does particle dust stay on a tomato skin in your urban garden? Does the tomato absorb it or does it wash off in a rain? What about raspberries, blueberries, hazelnuts? What about different herbs? What about beetroot and lettuce?
– compare the data gathered from urban environmental pollution monitoring on organically grown vegetables, with monitoring data of non-organically grown vegetables of industrial agriculture origin (pesticides, GMO’s, chemical fertilizers, … )
Sensors for air pollution monitoring:
– air pollution meter : air quality (optical→dust, O3, CH4, CO2)
http://sensorapp.net/?p=479 (optical dust sensor)
– carbon monoxide pollution meter
– lead pollution meter
– exhaust gasses pollution meter
Research paper:
Effect of air pollution on peri-urban agriculture: a case study

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Companion planting is the planting of different crops in proximity (in gardening and agriculture), on the theory that they assist each other in nutrient uptake, pest control, pollination, and other factors necessary to increasing crop productivity. Companion planting is a form of polyculture.
Companion planting is used by farmers and gardeners for many reasons. For farmers using an integrated pest management system, increased yield and/or reduction of pesticides is the goal.For gardeners, the combinations of plants also make for a more varied, attractive vegetable garden, as well as allowing more productive use of space. Continue reading



Ecosystems include living organisms, the dead organic matter produced by them, the abiotic environment within which the organisms live and exchange elements (soils, water, atmosphere), and the interactions between these components. Ecosystems embody the concept that living organisms continually interact with each other and with the environment to produce complex systems with emergent properties, such that “the whole is greater than the sum of its parts” and “everything is connected”. Continue reading



During a few sunny spring weekends we work with a bunch of friends to install the farm on the parking rooftop Dansaert2, and to bring the farm to its full capacity: 44 containers of 125cm x 125cm. The containers are palox europallets, recycled from small fruit&vegetable companies. They are made of hard oad wood. We customize the containers on different heights, suitable for growing herbs, greens, roots and small trees.
The construction workers next doors help us to bring up soil and other materials with their crane. When the basic outline is nearly ready and the hardest work is done, I receive an assigned letter from the rooftop owner that we have 3 days to leave the place and that we have to restore the rooftop to its original function.

Reclaim the rooftops!

I keep the letters in which the owner threatens me by sending a process-server, and we plan the big move of the farm for easter weekend, 2012. I design a new Urban ArtFarm plan for the new location which is 1 roof up, but still with plenty of space. The new rooftop is located on another parking: parking Lepage. We empty the soil out of the 44 containers and lift them one roof up and we fill them again. We take the glass windows out of the greenhouse and we move the aluminium skeleton 50 meters to the left, on the new roof. Late spring 2012 (june 2012) I expand the farm surface with 10 more containers. This makes a total of 54 containers.

Moving the greenhouse from one roof to another, after the prohibition to develop the farm on the roof of parking Dansaert2.

planten-plannen voor een nieuw tuin:

Climbers : Hedera helix (klimop, 3 x) bloei oktober – goede pollen/nectarplant voor einde drachtseizoen; Rosa Canina (hondsroos, wilde roos 1-3 m) , bloei juni/juli – beeplant – The fruit has high vitamin C level and is used to make syrup, tea and marmalade; Rubus fruticosus thornless evergreen (doornloze braam) – beeplant – bloei mei/september (laten groeien op de groene afsluiting) – edible plant: berries & dried leaves for tea; Lycium barbarum (Goji bes, Boksdoorn) – uit zaad kweken! – klimplant – edible plant (bes) – arme grond – groeien tussen de bramen op groene afsluiting. Vitis vinifera (druif) , klimmen tegen muur zuid, edible. Zowel serre als buiten, verschillende rassen. Meeldauw resistent. (Boskoop Glory)
Trees (volle zon, in bigbags) => sterke paletten: Tetradium daniellii (bee tree 4 x), bloei juli/augustus , nectarplant; Vitex agnus-castus (monnikspeper), aromatisch, 1- 4m, bloei late zomer – medicinal plant, nectarplant, volle zon – bigbag; Sambucus nigra (vlier, 4m) – edible and medicinal – bigbag
Schrubs and small fruit: Hippophae rhamnoides (duindoorn) – pioniersplant, extreme t°, volle zon, arme bodem – edible plant (duindoorn jam); Viburnum opulus (Gelderse roos) – nectarstruik, 3 à 4 meter, (medicinal – menstruation problems e.a.) – bloei vroege zomer; Ribes nigrum (cassis, blackcurrant) – 1/2m – edible plant – vokka/cassis; Rubus idaeus (framboos) – edible, medicinal – bloei mei/juni – buiten en in serre.
Wild Flowers: Dipsacus fullonum (grote kaardebol) – 70-150cm, tweejarig – nectarplant – bloei, juni/september – matig voedselrijk; Cynara cardunculus (kardoen) – 80/150cm – volle zon – beeplant – edible plant; Foeniculum vulgare (fennel) – beeplant; Echinops ritro (beklierde kogeldistel) – 60/200cm – zonnig, bloei juli/augustus – open plaatsen – matig voedselrijk – beeplant; Helianthus annuus (sunflower) – sunny, flowers late summer – beeplant – edible seeds – fertile, well drained soil; Achillea millefolium; Althaea officinalis (heemst) – 60/150cm – medicinal plant – bloei augustus/september; Carthamus tinctorius (saffloer) – distel, 80-120cm – edible (bloem).
Herbs: Angelica archangelica (engelwordel); Anthriscus cerefolium (kervel); Echium vulgare (slangekruid) – nectarplant; Myrrhis odorata (roomse kervel) – tall tot 2m, perennial, edible (leaves) herb.; Phacelia tanacetifolia (phacelia) – beeplant; Porophyllum ruderale (quilquina) – edible, blad – smaak = coriander/rucola – 70 cm – bolivia; Chenopodium bonus-henricus (brave hendrik) – 15-60cm – bloei mei/augustus – edible, jonge bladeren als spinazie; Crithmum maritimum (zeevenkel) – 20/50cm – bloei juli/oktober – aromatisch – edible: bladeren vóór de bloei, smaakt naar asperges (Pelio/ Damouchari!) samphire; Fenugriek; Stevia; Satureja montana (bonekruid)
Vegetables (greenhouse): tomaten; aubergines; courgettes; komkommer; meloenen (serre); paprika
Vegetables (rooftop): tomaten; pompoenen; spinazie; snijbiet; mais; sluimererwten; tuinmelde; broccoletto; spigariello; rode biet; zeekool; palmkool; tuinbonen; boerenkool; struikbonen



We connect local OpenGreens in an international network of experimental gardens where artists work with natural processes.
These gardening situations serve especially to look into microsociological and ecological systems related to time as starting points for the development of new artistic practices. The OpenGreens allow us to study the implementation of contemporary art in an ecological context and to observe and draw content from eco-data and natural patterns and processes.
Using media technology and electronics as research tools in these shared laboratories, data from various ecosystems are collected over a period of time. Continue reading



I discovered that the location of the 2 rooftopgradens has a rich history, tracing back to 1235, when the convent of the ‘White Sisters’ was established. In 1456 Philip the Good integrated the White Sisters in the cloister of Jericho. The address was on the Oude Graanmarkt, right around my corner, and their land had a surface of 4 hectares. They had vegetable gardens and orchards and even their own brewery. It is great to know that we can add another layer on top of this wonderful history. Continue reading