Opinions for RDWC system.

Hi, I'm building a new RDWC system and I wonder if I'm setting it up right:

•16 pots, ~4 gallons each in 4 rows + reservoir (Total NS volume around 50gal).
•Canopy area is ~43 ft^2 (6,5x6,5 feet).
•Lighting is 4x BESTVA 1000w (~200w real wattage) led panels plus a 600w HPS for flowering (panels evenly spaced, HPS in the center).
•Aireation trough commercial aquarium pumps, water is circulated from above (similar to bubbleponics). Don't remember pumps output but it's more than enough.

My thoughts are about the lighting, maybe I should get another 600w HPS but I fear my home installation won't handle it. Is it enough with the four panels and one HPS? I top and lollipop for training, keep them relatively low (around 3 feet).

I think you are gonna Want more lighting for sure.

diggs99 said:

I think you are gonna Want more lighting for sure.

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Yeah maybe do one grow and see how it goes, then get another sodium. I should also change the electric installation so it handles more amps.

So you are working with 42.25 square feet of canopy.

With HPS we want 50 - 60 watts per sqft in flower.

With cheapo LED you want 40 - 45 watts per sqft in flower. With high quality LED 35 watts per sqft is great.

So, multiplication reveals that you are way short on lighting. 800 watts of the LED panels is good for about 20 sqft and the 600 HPS is good for around 10 - 12 sqft. So you need another 600 in there to get things where you wanna be.

You can get away with less light in veg but flower you really need it or yields suffer greatly.

Renfro said:

So you are working with 42.25 square feet of canopy.

With HPS we want 50 - 60 watts per sqft in flower.

With cheapo LED you want 40 - 45 watts per sqft in flower. With high quality LED 35 watts per sqft is great.

So, multiplication reveals that you are way short on lighting. 800 watts of the LED panels is good for about 20 sqft and the 600 HPS is good for around 10 - 12 sqft. So you need another 600 in there to get things where you wanna be.

You can get away with less light in veg but flower you really need it or yields suffer greatly.

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Thanks for the math. I've been growing for years but always outdoors, this would be my second grow indoors, last one was average. I read a lot on lights and coverage but information is so contradictory, especially about leds. Then I'll get another sodium before going into flower, that should be alright.

Patito92 said:

Thanks for the math. I've been growing for years but always outdoors, this would be my second grow indoors, last one was average. I read a lot on lights and coverage but information is so contradictory, especially about leds. Then I'll get another sodium before going into flower, that should be alright.

Click to expand...

Yeah it's somewhat of a mystery and LED manufactures claims make it very difficult. I think that adding the second 600 HPS during flower would be perfect. For veg you are fine with what you have IMO. You will need to cope with the extra BTU's and infrared emissions that will effect canopy / leaf surface temperatures.

With HPS we need cooler canopy temperatures than we do with LED. This is due to the IR light that the LED lacks which warms the surfaces it hits but not the air. So for optimal leaf surface temperatures on all your plants you will have to tweak things for sure. As an outdoor grower you probably have a good eye for happy plants and that will be the skill to rely on. I think you will do very well.

Also, remember as biomass increases the transpiration of humidity will as well.

Most of the heat from the LED lights will come off the heat sinks and drivers and radiate upwards. Placing your hand under the LED and then the HPS you should feel the warmth from the IR under the HPS but not so much on the LED. Both will have heat radiating off the top.

Then I'll definitely redo the electric installation, so I can plug an AC. Thanks for the replies, when it's all nice and done I'll post a thread with some photos. Have a nice holiday