The location must meet certain statical requirements, meaning that the subsurface – consisting of soil, road, fill, etc. – must be sufficiently firm and dense. In the case of an underbuilt area, it must be loadable in accordance with the requirements (see also the following question).

In addition, the following technical requirements must be met: frost-proof water connection, access to electricity and, if necessary, WiFi and lightning protection.

Depending on the location, type and size of the planned VERD° system, there are different requirements:

a) Soil, unsealed surfaces: For these locations, a soil survey is required, from which one can infer how the VERD° modules can be secured. If ground screws, poured or raised foundations are to be used, site-specific calculations must be carried out depending on the intended use.

b) Substructure (e.g. underground car park, underground tunnel, bridge): In these cases, the construction documents must be reviewed in order to check the permissible load per square metre. If the substructure is found to be suitable, the planned VERD° modules can be secured either with raised foundations or by bolting them directly to the substructure.

The design of VERD° SPACE and VERD° KIDS is modular. The modules can be disassembled, moved, and set up again at a different location after one or several years. If this requirement is known beforehand, the second location can already be planned for when configuring the VERD° system.

The water connection can be up to about 75 metres away to still allow for a sufficient water pressure in the pipe. However, the installation will be the easier the closer the water connection is situated. The water supply pipe needs be frost-proof and should be laid at least 60 to 80 cm deep into the ground. A water connection with hoses above ground is also possible, but only during the season and in secure, non-public locations.

For plant sails with an area of 210 square metres (which corresponds to a VERD° SPACE module with 8 sails), approx. 32 cubic metres of water are consumed between May and October (6 months). By comparison, an 80-year-old lime tree, which generates a similar amount of biomass and cooling, requires 48 cubic metres during the whole year. Both types of shade providers are therefore comparable in terms of water consumption.

Absolutely! If it is possible to use or install a cistern, rainwater should be used. The volume of the cistern should be calculated accordingly, or there would have to be the possibility to replenish the cistern by means of an additional water connection if needed. In any case, there always needs to be enough water available.

During heavy rainfall, the water reservoir at the bottom of the planter fills up first. Once it is full, the excess water can run off through the openings intended for this purpose, so that the plants are protected from “flooding” and root rot. The sizes of the different planters are calculated in a way that the substrate or plants at the top cannot be washed out.

The plants consume the water and return it to the city and its inhabitants in the form of humidity, cooling and shade. The greening contributes to making inner cities more climate-resilient and protecting people from the heat. For this reason, the use of drinking water to irrigate urban green does make sense – and cannot be compared with uses such as the filling up swimming pools or watering lawns.

The plants must grow quickly and be insect-friendly, i.e. they must have flowers that produce nectar and/or pollen. The plants must also be able to withstand intense sunlight and high temperatures. The ratio of leaf surface area to leaf thickness is an important factor here: the thicker and smaller the leaf, the more heat-resistant it is.

Perennial plants require a significantly larger root space than annual plants (min. 80 cm vs. approx. 40 cm deep), mainly to be frost-proof. Root space of this size is increasingly difficult to find in our highly compacted and sealed inner cities. The significantly smaller root space of annual plants also allows for non-soil-bound solutions: The relatively small and light-weight planters used for VERD° can be positioned at a height of 3 metres, so that traffic routes or the precious urban space below remain useable.

Further advantages: Annual plants grow significantly faster than perennials; they do not lignify which reduces fire loads; and they do not require costly and time-consuming pruning or disposal of foliage in autumn.

Partly yes, partly no. Some of the plants are native, or have been used in Central European horticulture for centuries. But as extremely high summer temperatures are becoming the norm due to climate change, we need to rethink our approach and work with plants that can withstand these new climatic conditions.

For VERD° installations whose nets are within reach of people, we only select plants that are non-toxic and do not cause any irritation when consumed or touched. For installations with planters at a 3 metre level, i.e. out of reach for people, we also use plants that may cause slight irritations, such as the moonflower. One of the reasons for this is that these species are very popular with certain insects such as moths and make a valuable contribution to biodiversity.

The plant combination is always determined specifically for each project. Criteria for the selection include the location and the accessibility of the plants for people. Shape and colour can be a factor, as well as the contribution to the promotion of biodiversity. The Senckenberg Gesellschaft für Naturforschung is conducting research on which plants are preferred by which insects. This will enable us to address local insect populations more precisely in the future.

We work with various edible plants: Malabar spinach, nasturtium or La Mo Long (cheese plant) can be eaten raw. There are small cucumbers that are mainly used in kindergartens (“snack garden”). There are also different kinds of beans which can be harvested and cooked.

We work with a combination of fast-growing and slower-growing plants. Like this we can ensure that the plant sail is fully covered as quickly as possible after planting, but also remains green as long as possible. The growth rate of the fast-growing plants was one metre per week in our 2023 prototype.

All product variations of the VERD° system are modular and can be configured individually. Based on the location and usage scenario, the number of modules, format, orientation towards the sun and foundation above/under ground are analysed, calculated and determined in close cooperation with the client. The combination of plants can also be determined on a project-specific basis (see question “Can the plants be combined individually?”).

For the planning of a VERD° installation, OMC°C collaborates with architecture, horticulture and urban planning offices or, in the case of public clients, directly with the respective municipality and relevant local authorities. We know from experience that there will always be aesthetic, functional, static and organizational issues which need to be discussed and coordinated with multiple stakeholders.

As VERD° is a serial product and the number of foundation options above/under ground is limited, the planning effort can be estimated quite well. In general, a period of 6 to 8 months can be expected from initial contact to installation. For larger, more complex greening projects, one needs to allow for a longer planning period.

VERD° modules can be combined freely and in any number. The height at which the planters are installed can also be flexibly configured and is between 50 cm and 300 cm above the ground. The positioning of the planters will have an effect on the total height of the plant sails and accordingly on the size of the shade area created. Their position also determines whether the plants can be experienced at eye level or whether the area below the sails can be used for sitting, walking, cycling, or other activities.

The colour of the supporting structure cannot be customised. The metal is galvanized, as this is the most durable and robust form of coating. The wood is not treated and will turn grey over time, except for the components that are exposed to rain and are therefore protected by a coating. The biodegradable flax net, which is recycled together with the biomass in the autumn, retains its natural colour. In the end, it is only the colour of the planters which can be customised within certain limits.

The construction of all VERD° variants is designed, in accordance with German and European building regulations, to withstand the strongest measured storm of the last 50 years.

When fully greened, the large plant sails represent fairly high wind loads. These are secured in the different VERD° variants – VERD° SPACE, VERD° KIDS and VERD° FACADE – by different static approaches and an optimised load distribution. The anchoring above or under ground ensures that the structures do not “sail away” on the smooth surfaces of public squares and roads. This is why the nature of the ground must be examined for each project right at the beginning. The supporting structure is designed to use as little material as possible and with the aim to achieve an optimal balance between refined aesthetics and maximum safety.

The structural calculations were carried out by the renowned engineering firm Bollinger + Grohmann.

To protect the plants and nets in public spaces from vandalism, the planters in the VERD° SPACE and VERD° FACADE variants are installed at a height of 3 metres. This protects the plants from accidental and affective destruction. Ultimately, however, tagging and graffiti cannot be prevented. Fortunately, we had very positive experiences with our prototype installation in Frankfurt's university district: despite daily and nightly use, there was no soiling or destruction. From what we could observe, people in the neighbourhood perceived the VERD° modules as a friendly space and meeting point and treated them respectfully.