FA info icon.svg Angle down icon.svg Project data
Type Vertical garden
Vermicompost system
Authors Camila Ribeiro Matos
Pamela Melo
Location Arcata, California
Status Deployed
Years 2015
Cost USD 138.85
OKH Manifest Download

Vertical Garden is a state-of-the-art vertical growing system that is an ecological nutrient recycling system. It's perfect for rooftops, patios, balconies, terraces—just about any relatively sunny place outside. Easy to manage by having a mobile structure and not too heavy, featuring a cylindrical frame which involves multiple sites with plants growing food with a central pipe that is disposed decomposing food remains.

The garden tower is highly practical because it combines several benefits at the same time. By using food remains to feed the compost-nutrient delivery system vermi integrated, thereby contributing to the reduction of waste food and litter, and consequently lower consumption of purchased food.

Background[edit | edit source]

Fig. 01 - Site that will locate the garden tower.

The CCAT Vertical Garden is located at the Campus Center for Appropriate Technology (CCAT) at Cal Poly Humboldt, Arcata, in northern California, USA. CCAT is a sustainability-focused organization with the objective to disseminate information about appropriate technology in a live-in laboratory.This project,vertical garden, was created in Spring-2015 by Camila Ribeiro, Fernanda Franco, and Pamela Melo in association with CCAT.

A Vertical garden, also known as green wall, is a modern technique of landscaping increasingly widespread in the world.[1] The advantages of this technique are: improving air quality and humidity, acoustic and thermal insulation, and the use of small spaces to accommodate a variety of species of plants (ornamental or food). This new type of landscaping began with the French botanist Patrick Blanc, who specializes in tropical forest plants, being responsible for the innovation and the popularization of vertical garden. The garden can be deployed indoors or outdoors.

Problem statement[edit | edit source]

The objective of this project is to develop a garden that would utilize the least amount of space and be a good source of food for the Campus Center for Appropriate Technology (CCAT). In order to develop an effective project, we aim to:

  • Choose a location within CCAT property that gets enough sunlight to the plants;
  • Design a vertical garden that will make it possible for food growth;
  • Choose native species of plants.

Criteria[edit | edit source]

The criteria were chosen based on the interests of CCAT. ItThe criteria will help evaluat the most appropriate technology for the CCAT Vertical Garden. The scale represents the importance level from 1 to 10, where 1 is the less important criteria to 10 (most important).

Project Criteria Constraints Weights
Food The food production most be abundant. More is better. 10
Durability Most be resistant. More is better. 10
Sustainability Greater is better. 9
Use and Maintenance Most be easy to use and maintain. Easier is better. 8
Educational Value Greater is better. 7
Cost Less is better. 6

Literature Review[edit | edit source]

Material Used in The project[edit | edit source]

Fig. 01 - Barrel used to build the Vertical Garden.

The use of plastic drums is a versatile and cheap way to set a structure for a vertical garden. The plastic manufacturing process is essentially the recovery and recycling of waste polymers, since their natural decomposition process is long and critical to the ecological balance.[2]

High-density polyethylene (HDPE) has important qualities such as durability, waterproofing, corrosion resistance and ductility. Due to its flexibility HDPE is less susceptible to damage from extremes such as vibration and shock. HDPE has excellent water resistance without holding the oxygen or carbon dioxide.[3]

The physical aspect of the soil refers to the texture and structure. The texture of a soil is relates to the size of the grains formed. Soil has varying amounts of sand, clay, organic matter, water, air and minerals. The manner component is the soil structure. A well-structured soil should be fluffy and porous allowing the penetration of water and air, as well as small animals and roots.

The chemical aspects of soil are related to nutrients that will be used by plants. These nutrients dissolved in the soil water (solution) penetrates through the roots. In organic production system nutrients can be supplied by adding organic matter and plant compounds.

The biological aspect deals with the existing living organisms in the soil, working in physical and chemical aspects of the soil. Life in the soil is only possible where there is sufficient air, water and nutrients. The presence of living organisms indicates good soil structure. Soil microorganisms are the main chemical transformation agents of nutrients, making them available for absorption by plant roots.[4]

There are specific characteristics of seeds that one should considerer when planting a garden, such as the time of planting, purity and germination percentage of the seeds available and harvesting cycle. Choosing the best seed variety is related to germination rate, development plant, attack resistance of pests and diseases, productivity, product appearance, flavor. Each vegetable has its own characteristics as to the life cycle, preferred time planting, water requirements, nutritional requirements. For example, in rainy times there can be problems with waterlogged soil, making it harder to harvest roots and bulbs.

It is important to organize seeding according to what is intended to be harvested. For this, data must be analyzed for each culture.[4]

To avoid weeds and conserve soil moisture, its recommended the use of padding of plants and composting coverage application or tree chips. The removal of weeds can be a difficult task, so its easier to avoid them to grow. For this, one of the safer and more efficient methods is depriving these herbs of light and air.[5]

Landscaping[edit | edit source]

The landscaping is defined as the art and technique of promoting the design, planning, management and preservation of open spaces, urban or not, in order to render the micro and macro landscapes.[6]

Alternative gardens may be used as a method of urban afforestation. Alternative gardens are a practical, economic and modern technique, which can be produced in any environment, internal and external, small or large. Moreover, they are a way to collaborate with the environment, reusing materials that would be discarded.

Urban trees, vertical gardens, green walkways, living roofs, and filter gardens are techniques that besides improving the look of the environment are helping to improve environmental quality, especially in large urban centers. The benefits of these green techniques are decreased heat, increased moisture, decreased erosion, better drainage of water, environmental preservation and attraction of birds.[7]

Vertical Garden[edit | edit source]

Fig. 02 - How the Vertical Garden works - See more at:

The Vertical Garden is a tool used in landscaping and consists in coating walls, internal or external, and using diverse vegetation in order to improve environmental quality. These benefits include temperature and moisture, but also aesthetics, helping and mitigating the lack of green areas in urban areas. Vertical gardens are an excellent dust and noise reduction strategy, they protect walls against the sun, and also assist in carbon sequestration and improving the quality of human life.[1]

Vertical gardens are a relatively new technology and require little space, which is a great advantage, since in most cities the space for landscaping is scarce, especially in densely populated areas.[8]

Thus, a vertical orientation may be provided for effectively displaying a number of plants or vegetables, creating a pattern to provide an aesthetic view, to maximize the use of the space, to increase the capture of existing light, or to simplify care or irrigation of the plants.[1]

Agriculture[edit | edit source]

Agriculture includes all work related to soil treatment and greenery. Agricultural activities are intended for food production and obtaining of vegetables, fruits and grains.[9] The emergence of agriculture was an essential step in the development of humanity. Historians claim that during the Neolithic Age, the man that before was used to hunt, fishing and harvesting started using agricultural and livestock activities. The wheat and barley have been the first plants to be cultivated.[10] It is believed that people began developing agriculture when the temperature become milder and the food scarce in certain regions.[9]

With agriculture it was possible to increase the amount of food available to people. In the other hand, the society became sedentary. Agriculture allows for human settlements exist with higher population density than can be supported by hunting and gathering.[10]

Food Production[edit | edit source]

Consumer concern about food has grown in recent decades.[11]Previously, food was eaten primarily to survive, so food quality was not a priority.

During the 1950s and '60s, people worked to improve the food production chain, with the development of new additives (preservatives, stabilizers, thickeners, etc.). Research in food technology took off, and in later years (the '70s and '80s), the focus of research wason the elimination of harmful components (resulting in, for example, non-alcoholic beer and decaffeinated coffee) as well as in food production with reduced sugars and fat ("light" and "diet"). In the '90s, food began to be seen as welfare Synonyms, reducing the risk of diseases, as well as being a vehicle for a better quality of life.[11]

Special products such as functional or organic foods lies in the evidence on the health effects of certain substances in foodstuffs, reinforcing the idea that food is a critical factor in maintaining health. Simultaneously, there was an evolution in the quality and purity of food, especially regarding items potentially toxic to humans, such as pesticides and antibiotics in animal products. This is partly due to the fact that agriculture is no longer considered in isolation from urban areas and the entire range of industrial and commercial activities involving food and beverage chains.[12] Food systems comprise all aspects of production, distribution and consumption of food. A connection between the quality of food and human health, coupled with the growing use of natural ecosystems around agricultural areas, is part of the new approach of the "food system", which includes the cultural systems that influence the values and beliefs of people about how to produce and consume food.[13]

Composting[edit | edit source]

Composting is a process in which organic material is used to create a good source of nutrients for plant growth. Basically, microorganisms decompose organic matter into molecules that plants can use for their metabolism. Good compost has a good ratio of carbon and nitrogen. A good carbon (C) source comes from vegetables, and nitrogen (N) is mostly present in animals waste. A good C/N relation for composting is between 20 and 30 (for every 2 or 3 parts of carbon there is one of nitrogen). In a composting process it is necessary to have organic matter, minerals, water, microorganisms, and oxygen. The process will generate heat, CO2, water, and the finished compost.[14]

There are some concerns in placing a compost chamber in the middle of a vertical garden, such as oxygen source. Without oxygen the microorganisms will utilize the nitrogen source and produce acids, ammonia, and methane gas (greenhouse gas with greater damaging potential to the atmosphere temperature than CO2).[15] Therefore, it is not our interest to have an anaerobic decomposition process happening. Another concern is the temperature, while decomposing the temperature can reach to 65° C, which can burn the composting material and the soil surrounding it.[14]

Vermiculture[edit | edit source]

There is a different type of composting called vermicompost, which is a process of decomposition utilizing worms. Vermiculture combines microorganisms and worms for a faster process, producing less heat; this is perfect for our vertical garden project. The worms will eat the organic matter and its feces will serve as a nutrient source for plants. The temperature in the process can reach to 30° C, it is higher than the ambient temperature in Arcata, CA, but it is bearable for the plant's roots. There are many other advantages in using worms for composting, such as the production of compost tea, which contains a large amount of nutrients that can be collected and poured over the soil. The tea can be dropped directly in the plant foliage, and its nutrients will be available locally.[16] Besides, worms need a moist environment; if their skin dries out, they will die.[17] Therefore, it is important to irrigate the system regularly.

Construction[edit | edit source]

Adquiring the material

Adquiring the material:

  • 50 gallon barrel
  • 5 feet of PVC pipe 4"
  • Base to the barrel
  • Silicone Glue
  • Adpaters and Covers to bottom and top of the pipe
  • Tools (drill, knife, saw, etc.)
Cutting the barrel

To draw the site that the cuts will stay.

With a knife or a saw to cut the barrel.

The size of the cuts depends what kind of vegetable will be cultivated there.

Heat the plastic and open the holes

Using a tool that heats the plastic it was added a wood inside the holes in the barrel,

in order to increase the hole.

Make holes in the pvc and in the bottom of the barrel

Using a drill machine it was made a series of holes in the pipe.

A series of small holes in the bottom to drain water and also a big hole to fix the pipe.

fit and paste the pipe in the barrel

To fit the pipe into the barrel and using a silicone glue to seal all the fittings.


To make the foundation that will suport the barrel.

In this case it was recycled a movable metal frame and made a hole in the metal to fit the pipe.

Can be also made using wood or cement.

Fit the barrel in the basis

To attach the barrel to the basis with screws in order to stay well fixed.

Fixing the pipe

In order to keep the pipe fixed, it was added a piece of metal inside the pipe fixed in the barrel.

Add soil

To add soil in the barril. Do not add inside the pipe. It is recommended to use a gardening soil because it is already fertilized.

If it was used another type of soil maybe it is necessary fertilizes it.

Plating Starters

After added the soil, it is time to plant the starters or seeds of the vegetables and to water. In this case it was used starters.

After planting is necessary to water the soil.

Add Kitchen scraps and worms

Inside the pipe add kitchen scaps and worms. Maintain the pipe covered.

Timeline[edit | edit source]

Date Activity
02/17/15 Acquired 50 gallon barrel.
02/20/15 Barrel cuts.
02/26/15 Open holes in barrel.
04/09/15 Acquired 4" PVC pipe and adapters.
04/16/15 Opened holes in pipe, attached it to barrel
04/23/15 Attach barrel to supporting base.
05/01/15 Buy soil, plants, and worms.
05/02/15 Fill barrel with soil, put plants, put food waste and worms.

Costs[edit | edit source]

# # Unit Material Source Unit Cost ($) Total ($)
1 Unit 50 Gallon Barrel Mad River Garden 32.24 32.24
10 foot Pipe Pierson Building Center 0.99 9.99
1 Unit Fitting Cap Pierson Building Center 2.49 2.49
1 Unit Threaded Plug Pierson Building Center 2.99 2.99
1 Unit Fitting Adapter Pierson Building Center 3.99 3.99
3 Bag Soil Mad River Garden 7.49 22.47
6 Pack Starters Mad River Garden 2.99 17.94
1 Unit Transportation Plaza Cab 11.25 11.25
1 Pound Warms Eureka Market 30.00 30.00
1 Unit Silicone Glue Pierson Building Center 5.49 5.49
Total Cost $ 138.85

Operation[edit | edit source]

The operation of the Garden Tower is very important to maintain the efficiency of the garden. If not done properly, the plants may not be able to develop and the resources put into it can be waste.

Maintenance[edit | edit source]

Like any other gardening, the Garden Tower needs especial maintenance. It is important to keep the soil humid, avoid shadow spot, remove undesired plants. The difference of this project is that it has a composting chamber, and knowing how to use it can make all the difference for the plant development.

Worm Tea[edit | edit source]

Everytime you water the plants, part of the water will drain in the bottom. This water is called worm tea, it is filled with nutrients and it can be pour back in the leaves of the plants, which are able to extract the nutrients in site.

Composting Tube[edit | edit source]

Initially, it is necessary to add kitchen scraps for at least a week before adding worms. They don't eat fresh vegetables, only the ones that are already being decomposed. It is recommended to use smaller scraps to a faster decomposing. Do not add any meat or daily products, and avoid avocado pits, corn cobs, etc. It is also recommended to use a bedding material in a ratio of 2:1 (to every 2 parts of kitchen scraps, 1 part of bedding material), such as shredded paper or potting soil, it will help in the drainage, air flow, and nutrient balance.

The best species of worm to be used are the Red Wiggler. To start it is only necessary to add 1 cup (2 oz.) in the tube. They will naturally reproduce inside the tube, and they can be reutilized after the compost is done. The tube can be empty two to four times at year, and a portion of the material must be returned to the tube.

Plant selection[edit | edit source]

You can plant vegetables, herbs, and flowers in the garden tower. It is recommended to use starter plants with 3 to 6 inches in size. It is better to put carrots, peppers, garlic, tomatoes, etc. in the top of the tower. In the bottom you can put plants that pour into the ground as compact melons. After removing the plants, you can pour the roots in the composting tube if they are not too woody.

Schedule[edit | edit source]

  • Water plants.
  • Add kitchen scraps.
  • Add bedding material
  • Get remained water and trough it in the top again.
Every 3 to 6 months (when composting tube is full)
  • Remove composting material from the bottom
  • Add a small part back to the tube
  • Add more worms
  • Change plants.(If needed)

Instructions[edit | edit source]

Adding kitchen scraps

To start, add 10 inches of kitchen scraps inside the pipe and 5 inches of bedding (shredded paper and/or soil).

Adding worms

To add 2-4 cups of worms. Make sure to select a species that is adapted to the environment which is situated the garden.

Making composting

To add regular kitchen scraps above the composting. Make sure do not add meat or dairy products and it also recommended to put the scraps in the smallest part to improve the compost rate.

Drawing composting

To empty composting into easy acess in the bottom of the pipe and to pour compost on top of barrel to enrich soil.

Watering soil

To water the soil at the top of the barrel regularly.

recycling water

To collect the excess of water in the bottom of the barrel and to pour on the top of the barrel (compost tea).

Conclusion[edit | edit source]

Testing Results[edit | edit source]

It is hard to have immediate results in a garden project. It is necessary to wait and see how the plants and the vermicompost develop. However, a proper maintenance is essential for this project to work. Plants need to be water often as any other garden. As the structure of the garden, we are very optimistic it will last. We used strong material, and we were very careful to built it; always thinking in the future of the project. We believe the tower will be useful for a long time.

Discussion[edit | edit source]

The garden is believed to run it's own cycle of nutrients. Therefore, we strongly believe that there will be no need to change the soil or even fertilize it. One suggestion is to use the compost from the bottom to replant seeds, or pour it to the top soil.

The compost chamber is the key in this garden, and it needs to be checked if the worms are still alive, if they are consuming the material, if the temperature is not to high, etc. If any of these problems are to be found, we may need to overcome by finding the source and trying to fix it.

Lessons Learned[edit | edit source]

In the process of building this garden we overstepped some difficulties, specially related to tools for this process. It was essential the support we had from other members of CCAT, and the university's professors who helped to overcome the difficulties. Talking to a more experience local person is the key to make your project work.

Another very important lesson we learned is that we need a good method to hold the pipe to the barrel. In our project we used a metal bar on the top to avoid it from going down. At first, we were using only silicon, which did not hold.

Next Steps[edit | edit source]

Hereafter, we need to continuously take care of the plants, fill the vermicomporst chamber, and remove it when it is done. In one year the plants will need to be replaced, but no major changes in the tower is believed to be needed. As long the vermicompost is still happening, the required nutrients in the soil is believed to renewable.

Troubleshooting[edit | edit source]

The table below shows possible problems, causes and solutions that might happen with the vertical tower. For any others issues feel free to contact the members of this group listed in the bottom of this page. We will be happy to help.

Problem Solution
The worms are huddled into the pipe. Empty the pipe and put a part of the worms in the soil. This could happen because of the compaction of the soil,

and it is necessary to add worms into the soil, in order to cave tunnels and help in the soil aeration.

Unpleasant odor in the vermicompost. Empty and wash the pipe, removing the liquid that may be accumulated.
Over-water in the barrel and no water draining. Make more or bigger holes in the bottom of the barrel.
Decreasing in composting rate. You should add more worms in the pipe and smallest kitchen scraps.

Make sure do not add meat ou dairy products into the pipe.

Fungus in the tower. It is totally fine.
Vegetables are too big to the holes in the barrel. Increase the size of the holes in the barrel or to choose species of vegetables that are smaller.

References[edit | edit source]

  1. 1.0 1.1 1.2 BLANC, Patrick.The vertical garden: from nature to the city. WW Norton & Company, New York, US. 192 p, 2008.
  2. PIVA, A. M.; WIEBECK, H. Reciclagem do plástico. São Paulo: Artliber, 2004
  3. ReciclaBrasil- Gerenciamento, coleta, tratamento, destinacao e viabilizacao de reaproveitamento de residuos pos-industriais. Sao Paulo. 1994
  4. 4.0 4.1 TORRES. C. Manual Clube do Jardim- Horta Organica Domestica. São Paulo. 2008
  5. GREENWOOD. Pippa. London. 1998. Gardening Hints and Tips
  6. MACEDO, Silvio S. Quadro do Paisagismo no Brasil. São Paulo: Coleção Quapá, 1999.<>
  7. GENGO, Rita C.; HENKES, Jairo A. A utilização do paisagismo como ferramenta na preservação e melhoria ambiental da área urbana. Revista Gestão & Sustentabilidade Ambiental, Florianópolis, v. 1, n. 2, p. 55 - 81, 2013.
  8. COSTA, Carlos Smaniotto, Jardim Vertical. Web artigo <>
  9. 9.0 9.1 J. Porta Casanellas, M. Lopez-ACevedo. Reguerin, C. Roquero de. Laburu, Book: Edafologia: para la agricultura y el medio ambiente. 1994. 807 p.
  10. 10.0 10.1 KHATOUNIAN, C. A, Ecological reconstruction of agriculture. Book: A reconstrução ecológica da agricultura. 2002. 348p.
  11. 11.0 11.1 Conway, Gordon. Produção de alimentos no século XXI: biotecnologia e meio ambiente. Estação Liberdade, 2003.
  12. Brom, Frans WA. "Food, consumer concerns, and trust: food ethics for a globalizing market." Journal of Agricultural and Environmental Ethics 12.2 (2000): 127-139.
  13. Harper, Gemma C., and Aikaterini Makatouni. "Consumer perception of organic food production and farm animal welfare." British Food Journal 104.3/4/5 (2002): 287-299.
  14. 14.0 14.1 COOPERBAND, Leslie. The Art and Science of Composting: A Resource for Farmers and Compost Producers. Madison, Wis.: Center for Integrated Agricultural Systems, 2002.
  15. WSU. Anaerobic Fermentation.
  16. EDWARDS, Clive A., Norman Q. Arancon, and Rhonda L. Sherman. Vermiculture Technology: Earthworms, Organic Wastes, and Environmental Management. CRC Press, 2010.
  17. BOARD, Niir. The Complete Technology Book on Vermiculture and Vermicompost. National Institute Of Industrial Re, 2004.
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