Thank you so much! This is the most informative piece I’ve ever seen on this and answers a lot of the questions that I had.
I think you’re right that the HPS would suffice but now I’m second-guessing because, while I knew they were hot… I had no idea I was dealing with that kind of heat. Now I’m very hesitant to put one of those in an even moderately confined area.
This was also an excellent explanation on how the HPS would actually cost a great deal more within a relatively short period of time given the energy costs.
So now I’m back to the drawing board to decide on what specific LED fixture I need to look at.
Are you generally using 1000 W units? Or are most of your fixtures in the 400 to 600 W range… On first glance, they seem more popular
No problem. Glad you found it helpful.
Heat control is a huge consideration. I went with LED exactly because of that. Let me give you some examples. In my 5x5 tent in the 68F basement, my 1000W grow light running at 80-85% easily raises the temp in the tent to about 85-89F, at which point the exhaust fan comes on to vent the heat out.
In my 4x8 grow tent in the cool (this is early to late spring) unheated garage two 800W grow lights raise the temps to 82-83F. I generally don't vent the heat out from there.
Once you start venting heat out into an unheated garage, you will get a ton of condensation on the walls, windows, etc. Then you need to run a dehumidifier. If you start venting out loads of heat into a unheated, unisulated or lightly insulated garage, that becomes an even greater problem to deal with. Risk of mold development, etc.
I only have a 1000W light in my 5x5 tent. I don't need the full 1000W, but the 1000W bar light is wider, covering the tent pretty much from side to side, providing an even PPF across the board. An 800W light has a smaller footprint, leading to a significant PPF drop on the periphery. Rotatable bars like on my King Brite lights help with that, but only on the sides, not front and back. Other than that, a 800W light would have been fine.
In the 4x8 tent, two 800W work fine for me, providing a very good side-to-side coverage.
I also have another 600W bar light and 480W quantum light. The 600W light is over my 4x5 grow table and I run it at 60-80%, depending on plant age. I can also stick 3 fig trees on the side of the table there, but I also have a large window on the other side where the figs go, so they get plenty of supplemental light from the window on one side. It works.
The 480W light is good for 3-4 mature trees (or 7-9 small ones) for the initial 2-2.5 months, but won't provide good canopy penetration after that, which will lead to lower leaf drop. I also use it in combination with supplemental light from a large south facing glass door.
I would say, it all depends on how you want to use them, how many trees you want to light up, and what results you want to get. Start with one light and see how it goes. Once you play with it you will get a better idea.
In general, you want a minimum of 5 sf per mature fig tree headstarted in our climate in February, or 4 sf if headtarted in March. Assuming moving them outside in late May. Now, find a light that will provide an even 700PPF or more to cover your grow area and you will see some amazing results. Up to 180-200 figs per tree. Most of my later ripening varieties take about 100-105 days to ripen with this setup and transition outside in late May.