How Many Grow Lights Do Your Plants Need?
How many plants can you grow per grow light? Beginners or even people who grow indoor plants have this question in their minds. It is a frequently asked question because it is necessary to understand before setting up an indoor grow room or tent.
There are hundreds of grow lights available on the market, and sometimes, it becomes difficult to decide which one is suitable for your needs and how many plants you can fit under it.
Understand Your Plants First
There are many species and types of plants, and all have different requirements for lighting.
When you want to understand your plants, you need to consider two important things. The first one is the specific lumen/PAR your plants need, and the second is the canopy coverage.
What is Lumen?
It is the amount of light emitted per second. In simple words, it shows the brightness of the light and gives an idea of how many lights you need for a particular area.
What is PAR?
PAR stands for Photosynthetic Active Radiations. These are the radiations that plants use for photosynthesis.
Therefore, every grow light also have PAR value in their specifications, and it is measured in PPF (Photosynthetic Photon Flux). The unit of PPF is µmol/s. If you want PPF per unit area, you will have the specification PPFD.
Research Your Plants Specific Lumen/PAR Needs
First, you need to find out the lumen/PAR value of the plants you are growing. For instance, if you are growing tomatoes, you need to find out the lumen/PAR value that it needs.
Your plants need a certain PPFD for a certain period of time. You cannot give them light all day. Therefore, you need to select a PPFD and the suitable number of hours for that. For that, you need the DLI.
You can easily find the DLI value of your plants on the internet without any hassle. For instance, the DLI of eggplant is 20–30, tomato is 22–30, and small herbs is 10–12.
After finding out the DLI, you need to find the corresponding PPF/PPFD that you need to supply to the plants and the number of hours. You can search for the PFFD, DLI, and hours chart. Search for the required DLI and see the PPFD you need and the duration.
If you cannot find the chart, you can go to this link. Enter the time in hours and DLI to get the corresponding PPFD. For instance, if you need DLI 18, you can give 500 PPFD to your plants for 10 hours, 454 PPFD for 11 hours, 625 PPFD for 8 hours, or there can be unlimited combinations.
Determining Coverage for Your Canopy
The second important thing is the canopy coverage. Beginners usually get confused after hearing the term canopy. It does not mean the canopy of your tent.
Canopy refers to the parts of the plants that receive light. It can be the topmost parts and the bottom parts that receive the light.
Canopy coverage is calculated based on the plants you have in your grow room. All plants are considered and their parts that receive direct light from the grow light.
Get to Know the Grow Light
You need to understand how many plants the grow lights can cover, how many grow lights you need, and many other things.
The first important thing that you need to know about grow lights is the area they cover. Once you know this, you know how many plants you can grow and how many lights you need.
How Much Area Does a Grow Light Cover?
Grow lights have a certain range to cover. You cannot expect one light to cover all your plants; you might need to install multiple lights.
You can decide how much area your light can cover, what kind of plants you can grow under it, and the optimal height to place it in your grow room by looking at the PPFD chart.
We will demonstrate through the PPFD distribution chart of Spectrum X LED grow light and show what it means and how you can use it to know the coverage area of the lights.
Look at this image below.
First, let’s look at the PPFD chart at the height of 6 inches. The area is 5 ft x 5 ft. You can see the PPFD distribution around in the center and at 1ft, 2ft, 3ft, 4ft, and 5ft. The values at the corners are in the range of 805–827. If this is enough for your plant and you are ready to hang the light at 6 inches, this is adequate for a 5ft x 5ft area.
And we can also see there is a chart for the height of 24 inches. You can have a look at the minimum and maximum PPFD values. You can decide whether this is enough for you or not.
Choose the Right Grow Light for Your Plants
There are many types of grow lights for indoor plants, and you need to choose the right one for your needs. You also need to decide on the wattage of the lights. These two are essential while selecting a grow light for your grow room tent.
Determining the Necessary Wattage for Your Plants
In simple words, you can search for the lights that can provide the lumen/PAR you need and cover the grow space.
You can look at the wattage of different types of lights having the same lumen/PAR output. You will see that LEDs have a low wattage.
Plant Training Method Also Matters
Plant training matters as well because it decides how many plants will be able to get adequate light.
While selecting a grow light, you need to consider whether you want to train your plants or not. Let’s understand why.
Some growers give importance to training plants, especially when they have many plants and a big space. Plant training means training the plants to grow in the fashion you like. You create borders with the help of strings, and plants grow in that direction. Everything looks organized.
Originally published at https://medicgrow.com on November 25, 2021.
