Light is a form of radiant energy and diminishes exponentially from its source. The amount of radiant energy available to a plant is determined by how far away the plant is from the light source. In a process known as photosynthesis, plants convert the radiant energy from the light source (the sun or artificial lights) into sugars or fuel for growth. Indoor horticulturists have some advantages over outdoor gardeners in that they have heightened control over atmospheric conditions. This heightened control allows for accelerated growth rates and an extension of the growing season. To make an indoor garden or greenhouse efficient, some gardeners choose to employ methods that best utilize the given radiant energy available from the light source. In a greenhouse setting, a popular way to utilize the radiant energy from the sun is to set up a multi-tiered configuration. A multi-tiered configuration in a greenhouse also helps a gardener make the most efficient use of the given floor space. Indoor horticulturists can also reap the rewards of maximizing their light source’s radiant energy by configuring the plants on a multi-tiered platform. Indoor gardens are limited by the amount of radiant energy emitted by the light source and a vertical, multi-tiered set-up will best utilize the available radiant energy.

Multi-tiered Set-ups for Greenhouses

Greenhouses offer some heightened control over environmental conditions, while still giving the plants access to the most powerful radiant energy source around: the sun. All greenhouses have one thing in common — a limited amount of space. Although greenhouses come in a wide variety of sizes, the amount of space within the greenhouse is always a limitation. This is especially true for home hobbyists who generally have, relatively speaking, less space to work with than a commercial greenhouse grower. To maximize the space within a hobbyist’s greenhouse, many implement some sort of multi-tiered, vertical set-up. Multi-tiered gardens can be a very efficient way to maximize both the plants’ exposure to the radiant energy and the given space in the greenhouse. By stacking plants vertically, a greenhouse grower automatically makes better use of his or her floor space. There are many ways a greenhouse grower can implement a multi-tiered, vertical garden in a greenhouse, including shelving, vertical planters, and vertical hydroponic systems.

Greenhouse Shelving

Greenhouse shelving is the most basic and straightforward form of multi-tiered, vertical gardening. Using shelving in a greenhouse allows a gardener to stack plants on top of each other and better utilize the given floor space while maximizing the available radiant energy from the sun. There are different ways greenhouse shelving can be set up in a greenhouse. Most greenhouses are designed to have a south or west facing wall to take full advantage of the sun’s exposure. Generally speaking, the shelving should be set up in multiple tiers with the highest tier next to the wall that is opposite the side of the greenhouse that receives the most light (north or east facing wall). By doing this, the plants on the higher shelving will not shade out the other plants located down below. It is also important to consider the height of the plants being grown and their location in the multi-tiered set-up. Taller plants should be placed up higher on the tier system so they do not start to shade other plants as they grow (just remember to leave enough head room for their growth). Conversely, plants of a shorter stature should be placed on the lower tiers to ensure they do not get shaded out by taller plants. Where to place which type of plant is an important consideration when setting up a multi-tiered system in a greenhouse.

Vertical Planters

Vertical planters are either manufactured or homemade planting structures designed to hold plants in a vertical manner. Vertical planters are basically self-contained multi-tiered gardens. An example of a homemade vertical planter is a 55-gallon plastic drum with holes cut into the sides where the plants can be placed. Vertical planters are usually designed to be used with potting soil. Typically, these planters are watered from the top, which allows gravity to bring the nutrient solution to all the plants in the container. Strawberries and lettuce are just two of the crops commonly grown in vertical planters within a greenhouse.

Vertical Hydroponic Systems

Vertical hydroponic systems are multi-tiered systems that utilize soilless gardening in a vertical position. Most vertical hydroponic systems used in greenhouses are recirculating systems. This means the nutrient solution is collected in a reservoir and reused after each feeding. The nutrient solution is commonly delivered to the uppermost plant module and gravity is the force that brings the solution to the remaining plants down below. Vertical hydroponic systems combine the speed of growth associated with hydroponic gardening with the space-maximizing benefits of multi-tiered vertical gardening. When the nutrient solution’s temperature is kept in check, vertical hydroponic systems are one of the most efficient growing methods used in greenhouses.

Multi-tiered Set-ups for Indoor Gardens

As in a greenhouse, a vertical, multi-tiered set-up can help maximize floor space and exposure to the radiant energy within an indoor garden. In an indoor garden, the radiant energy used by the plants for photosynthesis is not provided by the sun, but, rather, an artificial light source. One of the most efficient ways to use an artificial light source for growing plants indoors is to hang the light vertically and surround the lamp with plants. Most high intensity discharge (HID) lighting systems emit radiant energy in a 360-degree circle. In other words, they emit radiant energy evenly from all sides of the lamp. As previously mentioned, radiant energy from a light source diminishes exponentially. The farther the light has to travel to the plants, the less radiant energy is available. A good example of this is the use of light reflectors. When light is reflected and redirected toward the plants (common for a horizontally positioned lighting system), some of the light must travel farther because it must first travel upward toward the reflector and then back down toward the plants. This makes the total distance that the light travels farther than if it reached the plants directly. This is why surrounding the light source with plants is a more efficient use of the given radiant energy. When plants surround the light source, the light travels a shorter distance before reaching the plants, thus providing a higher amount of radiant energy. Similar to greenhouse gardens, there are many different ways an indoor horticulturist can implement a multi-tiered, vertical garden, including stadium- or colosseum-style gardens and vertical hydroponic systems.

Stadium- or Colosseum-style Gardens

A stadium- or colosseum-style indoor garden can be a very effective type of multi-tier set-up to maximize the efficiency of an artificial light source. Stadium- or colosseum-style gardens are similar to the staggered seating in a stadium or colosseum, hence the name. The light source is positioned vertically in the center of the plants. The plants are then staggered around the light source in a manner similar to stadium or colosseum seating. This type of set-up minimizes the distance the radiant energy travels from the artificial light source to the plants, thus maximizing the available radiant energy. A basic form of indoor stadium- or colosseum-style gardening is shelving that allows the grower to place planting containers around the light source and stagger the plants vertically next to the light. With this set-up, the plants can be moved or re-positioned depending on their size to further maximize the radiant energy emitting from the artificial light source.

Vertical Hydroponic Systems

Vertical hydroponic systems can also be set up in a stadium- or colosseum-style to best maximize the available radiant energy from a grow lamp. Vertical hydroponic systems range from homemade stackable modules made from PVC to state-of-the-art pre-manufactured vertical hydroponic systems that come complete with pumps, tubing, and growing accessories. Most vertical hydroponic systems used by indoor horticulturists rely on irrigation lines to deliver nutrients to each individual plant. A series of tubes or gutters collect runoff and direct the nutrient solution back to the reservoir for reuse. A vertically positioned light source surrounded by a vertical hydroponic system provides the highest amount of radiant light energy.

Indoor horticulture and greenhouse gardening provide heightened control over most of the parameters that affect plant growth. To best utilize the given radiant light energy, some growers get creative in the ways they position the plants within their greenhouses or indoor gardens. Multi-tiered, vertical gardens are a great way to utilize the radiant energy from the light source. Both greenhouse growers and indoor horticulturists are limited by their given spaces. To maximize space and radiant energy, many indoor and greenhouse growers are implementing some sort of multi-tiered, vertical gardening technique. Whether a grower chooses simple shelving or a sophisticated automated vertical hydroponic system, he or she is sure to see the biggest return on investment when the given space and the available radiant energy are efficiently used.