emp plastic and hempcrete are part of Margot Krasojević’s recent material study whose properties are applied structurally to this project, whilst the hemp-based 3D-printed LED collection is recyclable as well as biodegradable, shortlisted in the 2018 LEAF awards.
The outdoor medical marijuana farm is located near Barcelona. Catalonia only recently legally approved medical marijuana growth, recognising it as the next frontier of agricultural growth.
This building is specifically designed for the cultivation of medical marijuana. Its criteria address the three stages of growth. The building is surrounded by hemp fields as hemp is the major contributing building material.
The clients asked for a transportable and sustainable marijuana greenhouse. The three stages of marijuana growth specifically for medical use need to sustain a high TCH level for epilepsy and other medical conditions (arthritis, pain relief, multiple sclerosis and tumour seizures). The Catalan climate is perfect for maintaining the necessary temperature, humidity and air circulation to ensure a good harvest.
The main cantilevered structure is built using hempcrete. The building is surrounded by miles of hemp fields, a plant which grows quickly and has been used for thousands of years as part of building material infrastructure. Hemp is a sustainable material which regulates temperature and humidity, yet when mixed with a lime-based binder it becomes stronger than concrete, making this building material breathable, capable of absorbing carbon from the atmosphere and locking it in. The process of organic hemp to a building material petrifies cellulose to strengthen it creating a type of stone stronger than concrete, sparing/saving the need for mixing toxic concrete on site. Hemp also offers a lightweight yet carbon-neutral (negative if insulated correctly) material which is invaluable for a safe sustainable building.
The design consists of three main areas addressing the three stages of marijuana growth.
The main cantilevered frame is made up of three compartments which contain a retractable drip-feed irrigation system, which can be wound in and out of this main hempcrete structure depending on the size of the external growth fields. The drip-feed irrigation system uses rainwater filtered through the containers into which the necessary nutrients are fed to attain a pH level of 6.5. This sustains a perfect feeding routine from seedlings, a vegetative stage through to flowering and harvest. This main primary structure also accommodates a deployable, inflated structure which provides the required climate for the three growth stages. It is an ETFE membrane-coated hemp-plastic, lined with filters intensifying LEDs to aid growth; the inflatable structure is not a complete surface as it is inflated in sections creating gaps for natural ventilation depending on the level and pressure of inflation. Air circulation prevents root rot, mould, nutrient and light burn. The entire structure needs to be flexible in order for it to breathe with the environment and the plants.
The internal platform of the primary frame holds a series of rectangular frames which pivot within the primary structure; these frames provide the required pressure for the drip-feed irrigation, which need to be flexible in order to cater to the potential harvest which may alter depending on the season.
The entire scheme is mobile. Once the vegetative stage is over, and the flowering stage begins, it is set as an automatic feeding frame until the harvest, after which the building moves to a new location.
The building’s primary frame is made from hempcrete which is made on site. It takes approximately four months for the hemp to grow on site after which it is harvested to produce hempcrete, a material that emits no moisture yet sequesters carbon from the environment. Hemp is also used to produce hemp plastic, a bioplastic which is not only biodegradable but also recyclable.
The filter-tinted hemp plastic, can be reused and reformed to deploy for the next harvest. Hemp plastic, is a biodegradable and compostable alternative to petroleum-based plastics, which can feed the farm’s hemp plants once recycled. It starts to biodegrade after 28 days; after 30 months, it is completely reabsorbed into the environment.
The LED lights – which are powered by solar panels – can vary from 300nm to a maximum of 1200nm depending on the growth stage. An alternative design allows for different yields which have different growth stages to coexist within the same deployable structure, but the environments are separate catering to the need of the growth stage accordingly. Using LED lights reduces the watering frequency of the cannabis plants.
The design’s drip-feed irrigation tubes follow paths through and around the building. They also act as an SCROG mesh which evenly increases the marijuana’s exposure to LED and natural light. The flexible irrigation tubes pump water and nutrients to the plants whether they are within the inflatable structure or outdoors when nearing harvest. These gravity-fed irrigation tubes are made from hemp plastic and are remoulded on site as necessary – they can also be 3D-printed using solar energy. This is a safe way of reproducing and recycling parts for the building’s growth process.
Essentially, the building is an environmental drip-feed irrigation system which is designed to provide the perfect growth environment for medical marijuana. Building materials sourced on site come from a similar plant as marijuana but without the THC levels needed for medical potency.