Growing Peppers Indoors with LED Lighting
On this page we will cover some of the basics for growing indoors.
First we need to know where to start. So here is where you start. plants need light but how much light. Ok so plants that flower and bare fruit need 25-40 MOLS a day. MOL is the amount of light over time. LUX is another term used to Measure light and PAR is yet another light measurement and PPFD is another measurement of light. But what one is the most important one. Well MOL is the best choice and it’s the main one to use because we know how many MOLs our plants need in a day. But how do we measure this and how much is the right amount of light.
Ok Peppers need 25-40 MOLs a day for good growth. Here is how to measure light and how much light you are going to need. So let’s start with the plants light needs . 25MOL-m-2-d-1 this is how much light flowering plants need in one day. so to brake that down you take the 25 MoL needed and divide it By 24 which is for 24 hours in a day. That gives us roughly 1Mol a hour but light is not suppled 24 hours a day. This is why intensity is so important.
Ok so here’s how to come up with the light you need. let’s say you are going to grow indoors with no sun light . Growing in a tent or a room. You need to make 100% of the plants light. So we measure that by uMOL-m-2-s-1 which is the strength of light on one Square metre pre Second. So we need that number to start with. So let say that number is 400uMOL-m-2-s-1.
Now to turn that into the amount needed in a day we take 400*60=24,000 that’s 400 times 60 seconds.now we take 24,000*60=1,440,000 that’s 24,000 time 60 minutes. Now we take 1,440,000/1,000,000 = 1.44MOL now we know how much light we have in one square metre in a hour. Now we times that 1.44 times hours let say 10 hours so 10 hours times 1.44 MOL-m-2-h-1 a hour 10*1.44=14.4MOL-m-2-d-1
so we now have the amount of light we can make with a light putting out 400uMOL. Our plant need 25MOL-m-2-d-1 but we only have 14.4MOL so we are short 10.6MOL. So for good growth we are going to need more light. Now things get a little tricky how much space do you have. Lets say you have a 4*4 space, and you are going to supply all the light needed. You would need a light that has a 800uMOL-m-2-s-1 rating. That would be enough light to make 28.8MOL in 10 hours. This amount of light would be adequate for good growth.
So let’s look at it this way we have one light that is 400 uMOL. This light puts out 1.44 MOL a hour so if I ran that light for 18 hours We would be able to make 25.9 MOL-m-2-d-1 a day.
Now we have a daily MOL that our plants can grow with but it’s only capable of covering one Metre squared. But we have a bigger growing area then one metre squared. So let’s look at area, using the same light as above that has a uMOL Of 400uMOL-m-2-s-1. We can hang the light higher and that will lower the intensity well raising to coverage area. So let’s say we now have two metres squared coverage but the light is now only 200uMOL-m-2-S-1. So now with 200uMOL we only have 12.9MOL we can give the plants in 18 hours. So really this is not going to give us enough light for good growth. Now in summary we need a light sores that can put out at a minimum of 400uMOL-m-2-s-1.
Now with the light intensity out of the way we can now look at light Spectrum. we have been growing using LEDs now for over 8 years. We custom built our LEDs and we have found that Peppers like a little more white and blue than they do red. We have also found that making LEDs for the different stages of growth is very beneficial as well.
when growing with LED light one would think that we can now put lighting closer to the plants canopy. Well yes and no if lights are to close plants well suffer from light burn. This is another reason we need the right umol for our growing area. In our experience we have found that having one point of lighting like the old days with HID lighting does not work anymore. With LED lighting we can give plants more than enough light. In fact we can give plants to much light.
So the trick with LED lights is to give just the right amount of light needed. So let’s look at it this way we have a 4’ by 8’ growing area we could get a LED light with a umol of 1500umol but now we would have way to must light in the middle of the 4 by 8 growing area because the radiation pattern would be 1500 umol at lets say 24 inch high and because our light is at 24 inch high it’s light would be high in the middle and less at the ends just like the old HID way. But with LED lights we have the means to have a even light so instead of having uneven lighting with one light. we can now use two lights to evenly cover the growing area with the right amount of light. So a 4 by 8 area would be best covered with two lights. one for each 4 by 4 area of the growing space. And now this gives us the ability to have different plant heights and we all know plants tend to grow to different heights. LED lighting give us the ability to move our lighting to Match our plants growth. And this is a great ability to have. We like to cover a 3 by 3 with 600 to 900 umol this lets us grow more plants with different heights in our growing area. 900umol to 1100umol is more than enough light.
So it is our recommendation that 600 to 1000umol for a lights out put is the sweet spot for using LED lighting. A LED light at 30 inch’s high with a umol of 900 would cover a 3’ by 3’ area very well and if you plan to cover a bigger area you need to brake it down into 3 by 3 or 4 by 4 for each light. So the new rule of thumb for LED lighting would be to have lights over lap by 6 inch’s with there radiation pattern this well make the outer edges of the radiation pattern of each light equal. And we end up with even lighting for our growing area. Here is a picture of a radiation pattern an LED light from the top down.
Here is a picture of a radiation pattern that would be on the floor or on the plant canopy as you can see the umol drops Considerably the further from the center. And as you can also that a light with a umol as low as the one in this picture. That having a umol of 400 at the center is not good. Because at the two foot mark the light umol is only 200umol which is not enough light and one would need a light every two feet to try and maintain a umol of less than 400umol.
We hope that this read was not to much to take in. The short of it all is you need one light for every 3’ by 3’ Of growing area and that light needs to have at least a umol of 600umol or higher but not to high or you are just going to waste power.