Myth Busters: Unraveling the Truths about Cascading Gardens

One of the options to surround oneself with greenery even in the city center is through vertical or cascading gardens. Benjamin Raich, the Sales Director of Němec company, explains how these gardens work and dispels some myths surrounding them.

Gardens and flowers are traditionally grown horizontally, flat on the ground. However, you offer vertical gardens. How do they actually work?

Vertical gardens are a relatively simple solution to fulfill the dream of green living or to enhance the working environment for people in offices and partially compensate for the lack of nature in the city. Essentially, it is a system of plastic self-watering pots in which individual plants are inserted.

Is it difficult to incorporate a vertical garden into an interior? Does it need to be planned for in the initial build?

It depends on the size of the garden. If you want a small one, let's say up to 4 square meters, there is no problem installing it even in places where it was not originally planned. However, for larger areas, it is better to have it included in the project from the beginning. Vertical gardens have become popular in the last ten years, so they are still gaining wider recognition. About eighty percent of the time, we install them in interiors where they were not initially part of the design, but we usually find solutions.

How long does it take to install the entire system?

It depends, of course, on the size and specific conditions, but for your reference - a three-member team can install a garden of approximately 25 square meters in one day.

What is absolutely necessary to establish a vertical garden?

The requirement is water supply, or at least the possibility to bring water to the specific location. A small green wall can be watered manually with a watering can, but in general, a garden larger than 4 square meters requires an automatic irrigation system and ideally a drainage system. As for water consumption, let's say 40 liters of water are needed for a 4 square meter area. Water needs to be replenished every two to three weeks, and from my own experience, I know that it's not convenient for clients, so we recommend an automatic irrigation system.

Can we say that automatic irrigation means a low-maintenance garden that doesn't require any further care?

Unfortunately that is not the case. Even with automatic irrigation, there is no guarantee that the greenery will remain consistently in perfect condition. While these gardens are sometimes referred to as low-maintenance, it is to some extent a myth. They consist of living plants that require not only regular watering but also other, albeit undemanding, care. They need systematic monitoring, dust removal, removal of dry leaves or withered flowers...

What are the light requirements? Can a potential lack of light be solved with artificial lighting?

It depends on the type of plants you prefer, whether you prefer flowering or just green plants. Non-flowering plants typically thrive even with lower light levels, but it is always necessary to assess the amount of light available in a specific location. Artificial lighting is usually necessary because from autumn to late spring, the lighting conditions in our latitude are insufficient for most commonly used plants. If the plants have sufficient moisture, they can survive with low lighting, but they may not be in optimal condition. Lack of light is usually manifested by stunted growth and fading. To ensure the prosperity of plants, it is important to provide them with appropriate moisture and light balance.

Vertical gardens can be seen in commercial and public spaces. They are often perceived as a luxurious feature. Can you outline the price range they typically fall into?

When considering a vertical garden with dimensions of 4 square meters, the price for installation without irrigation typically ranges around 60,000 CZK, while with irrigation it can be between 70,000 and 80,000 CZK. One irrigation system can support a garden with dimensions of up to 35 square meters, so it's important to carefully consider the size of the installed garden and the capacity of the irrigation system. However, it is possible to create a garden with smaller dimensions, such as 2 square meters, with a fully automatic irrigation system. Personally, considering the investment in irrigation, I would opt for a larger size.

What are the smallest possible installations, and on the contrary, what dimensions do the largest ones reach?

It doesn't make sense to install a green area smaller than 1 m2. For clients who want smaller gardens, we have a solution called LivingArt. It can be described as a living green artwork in a design frame with an edge of approximately 1 meter. However, you should consider that such an artwork has some weight. Due to the weight, it is necessary to carefully consider the load-bearing capacity of the wall on which it will be displayed. The installation should be entrusted to professionals. As for the largest garden, we have no limits. Just to give you an idea, this year we are planning to realize a green wall of up to 1500 m2.

Could watering potentially damage or dirty the background wall, or are such concerns unnecessary?

The entire system is installed on a pre-prepared fixing wall, which can be made of aqua panels or other waterproof materials. The vertical garden system is then mounted onto this prepared surface. Water is filled into the planters, and each planter has an overflow, so the board should not come into contact with water. In the case that you water the garden yourself, there is a possibility of overfilling the planters and water spilling onto the floor, or the drain may get clogged, for example, with a dry leaf. That's why we recommend regularly checking the system, approximately on a monthly basis, and installing a small collection container beneath the garden as a precaution.

What types of plants are suitable for planting on vertical walls? Isn't the selection somewhat limited?

We use thirty to forty different species, mostly subtropical plants. Green plants are predominant, but we also have orange, purple, and other colors available. The variability is very wide. We usually strive to fulfill all of our clients' diverse wishes. Some may want a wall in shades of orange, while others prefer green or a colorful jungle. We try to accommodate everyone's preferences, taking into account our experience and the realistic possibilities. For example, when there is limited space between the wall and the surroundings, we opt for smaller trailing species.

Do customers choose specific plant species, or do they prefer to leave the selection to you?

The majority of our clients have a vision regarding the color scheme of the garden, but they leave the selection of specific plant species to us. For most clients, a vertical garden represents a design element that is low-maintenance. They enjoy being pleasantly surprised by the end result.

Are succulents suitable for vertical cascading gardens?

Succulents don't require as much water. Since the principle of our gardens is to group multiple plants in close proximity, it is necessary to choose those that have similar or at least comparable watering needs. Growing water-sensitive succulents in combination with other flowers could lead to overwatering and subsequent rotting. Additionally, succulents have slow growth rates, and for cascading gardens, it is desirable for the plants to flourish and fill the empty spaces of the system.

Doesn't it tempt you to try out new and different plant species continuously?

When it comes to subtropical plants, we can also try unused species. It's one plant per container. I tell clients that if they feel like changing the plants, it's not a problem at all. We can incorporate plants according to the season. For example, during Advent and Christmas, you can add poinsettias to the picture, and in spring, fresh bulbous plants, which will instantly change the overall mood of the space. The fact that we have thirty tested and proven species doesn't mean that we can't experiment with others.

Could it happen that a large number of live plants in a space would cause excessively high humidity or potentially promote mold growth?

The task of the implementation company is to recommend the optimal size of the vertical garden. Simply put, the old saying still applies here - everything in moderation. It is always necessary to maintain the optimal ratio between the green area and the size of the interior. For example, if you were to cover all the walls with greenery, you would certainly encounter the issue of high humidity. To some extent, it is a compromise between design and functionality.  

Indoor plants are susceptible to various pests. Isn't there a risk of faster multiplication of pests, transmission of diseases, mold growth, and similar issues with green walls?

With a quantity of thirty plants per square meter, there is, of course, a risk of pests and other diseases occurring. It is important to monitor the condition of the plants regularly. Pests commonly appear during the heating season, from autumn to spring. No seller can guarantee that the plants are in perfect condition. Even if they appear healthy at first glance, their roots may be affected. It is important to continuously monitor the state of the plants. There are anti-fungal sprays that can be used preventively to strengthen the plants' resistance. However, if a plant is heavily infested, it must be removed.

What kind of guarantee do you offer to your clients?

One month after installation, we return to verify the functioning of the entire system. If we have used a plant that is not in good condition, it will show within a month. If any issues arise within that month, it means that we used the wrong plant, and we will replace it. The only plants not covered by our guarantee are those that die after more than four weeks. We provide a 10-year guarantee on the entire system and a 2-year guarantee on the electronics. We offer regular servicing, and if the client decides to maintain the system themselves, we provide detailed instructions on how to proceed with its maintenance.

What are your plans and visions for the future?

I would love to see many more vertical gardens. Currently, we are working on obtaining a grant for a pilot project involving warehouse facilities near highways. I wish to green them up. It is important for developers to realize that a metal warehouse near a highway is a significant intervention in the landscape, but there are solutions to visually soften it. The warehouses can be camouflaged with green vertical gardens. While indoor vertical gardens are a beautiful design feature, green facades in cities serve a functional purpose. For example, in hot summers when urban heat islands are formed, green walls can locally absorb heat and improve the climate. It would be great if building designs considered water retention tanks for irrigation, transforming every flat roof into a green oasis, working more with greywater, and ultimately connecting everything in a unified synergy.

The interview was prepared by Ladislava Protivanská