As a merchant, one of the most frustrating questions that I get asked all the time is, “How much area will this light cover?” Even worse is this question: “How many plants can I grow under this light?”
The reason both of these questions are difficult to answer is that there’s a whole lot more to it than just a simple cookie-cutter answer.
I have seen so many different garden lighting configurations over the years that it makes my head spin. Some growers want to see how few lights can be used in their garden space, while others try to cram in as many as they can. Extreme examples range from two 1,000-W lamps on movers covering four 4- by 8-ft. trays to four 1,000-W lamps over a single 4- by 8-ft. tray.
I decided to write this article after receiving the following email from a grower:
“I need to know about how much square footage your 1,000-W fixtures cover. For example, if I had a 3,000-sq.-ft. warehouse with a 14-ft. ceiling, how many fixtures would I need?”
There are several problems with this question. The total square footage of a building tells me nothing about how it’s designed. Many configurations can occupy 3,000 sq. ft.
Even when I'm provided with the dimensions of a grow space, it's still a challenge to recommend a number of lights to cover the space because it can’t all be dedicated to growing plants. Aisles are needed as well as access to entrances and exits, plus space for fans, filters and supplies.
Additionally, your arms are only so long. If you plan to access each plant individually, you will need to take this into consideration. Three- to 4-ft. trays are as wide as you can reach, assuming you have access to both sides. Any larger and some serious acrobatics might be necessary to maintain the garden.
Many people may look at the picture above and see a tree, but that's not all it is. This green plant plays a huge role in our lives, without us even realising it.
Green plants provide us with food. They are at the start of all food chains (see below) and are called producers as they can produce their own energy. Green plants provide us with fruits and vegetables and also feed other animals that we may then go on to eat.
Green plants play a big role in our lives but play a bigger role in our environment. The equation below represents the process of photosynthesis:
From this equation, we can see that green plants provide our atmosphere with oxygen and use up carbon dioxide. The real importance of this is shown when we look at the equation for aerobic respiration.
The equation below represents the process of aerobic respiration:
Respiration is the reverse reaction of photosynthesis which allows for the oxygen/carbon dioxide levels in the atmosphere to be kept constant.
The Big CO2 Issue
The oxygen/carbon dioxide balance is extremely important, as carbon dioxide is a greenhouse gas. The ever increasing world population has led to this balance being disturbed.
An increasing population means an increase in the need for housing, schools, hospitals and factories. For these to be built, areas of green land must be cleared, causing an increase in the amount of CO2 in the atmosphere. The increase in any greenhouse gas causes something known as The Greenhouse Effect and can lead to global warming.
The increasing population also means an increased demand for food and energy, leading to deforestation.