How many lights do I need to grow cannabis inside an industrial warehouse?
What are the commercial options for mediums and lights (HPS or LED)? I have 17,000 square feet. Do I need 300 lights or more? Also, how should I set up the clone/mother room? Should I have trays or just pots, no trays? I’m looking to veg in three weeks, ideally, or four weeks, max.
Thank you for your questions. First, when setting up a commercial growing facility, remember that automation is your best friend. The more equipment in the garden that can be automated, the better. This automation will, in turn, reduce the amount of work that you must do.
In many ways, the choice of medium and growing system comes down to the grower’s personal preference. Just about any growing medium can be used successfully. However, when gardening on a large scale, logistics—including disposal of the medium—should be considered.
Stone wool is lightweight and easy to transport, making it a good choice for large-scale gardens. It is also a great medium for top feed systems, which are the preferred system for growers with commercial-sized operations.
Top feed systems with trays or troughs are easiest to automate on a large scale. Still, while stone wool is commonly used by large-scale commercial growers using this type of system, any soilless medium can be used just as effectively with a top feed set-up.
The simplest way to determine the horticultural lighting requirements for a commercial garden is to think in terms of watts (W) per square foot of space. The typical high-performance indoor garden will provide 40-50W of artificial light per square foot of garden space. It is important to remember that we are talking about actual garden space, not the total square footage of the room.
Assuming your 17,000-square-foot facility will be filled wall-to-wall with plants, you should plan on providing a minimum of 680,000W of light (for example, you could use 680 1,000W HID lighting systems). You could possibly reduce the total wattage required if you are using induction or LED lighting systems in place of HID lighting systems.
Induction lighting systems and LED are more efficient at converting electricity into photosynthetically active radiation (PAR), which means they can provide the same usable energy as other technologies while consuming less electricity. That being said, intensity is crucial to the development of large fruits or flowers, which is why HIDs still remain the most popular choice for large-scale commercial gardens.
How long the plants are kept in the vegetative stage depends completely on how large you want them before initiating the flowering cycle. For most indoor growers, the desired size can be achieved in three to four weeks of vegetative growth.
For the cloning stage, again, automation will be a big factor in reducing labor and increasing efficiency. A dedicated cloning space complete with temperature, humidity, watering, and lighting automation will go a long way in making the transitions of a perpetual garden smooth. The mother plant(s), however, are typically kept in a soil container and in a separate area or room.