The 1/5th the output of Red LEDs in the form of Far Red LEDs gives a nice trade-off for overhead lighting by improving ripenness, without inducing too much subcanopy stem elongation.

Optimum surface lighting wattages for ripeness may be used in the 1 to 1 ratio, but without providing more Red to the bottom of the canopy, the stem elongation would be excessive at usual indoor intensities. Higher Far Red ratios raise the (Red) saturation levels needed near the bottom of the canopy.

Incandescent Users: Many LED marketeers equate the amount of Red generated by their LED wattage to a given amount of HPS wattage, a quick and dirty rule of thumb for using Incandescents as a Far Red source is to use an equal amount of Incandescent wattage to HPS wattage. (In other words, using ten times the wattage of Inc.'s to Red LEDs is not unrealistic, just very inefficient compared to an equivalent amount of Far Red LED wattage.

For Simple Rauber Enhancement (No Far Red, just Standard Indoor Darkness (SID) intervals) or just good combinations of 415nm to 445nm Blues with Reds, having the Red and Blues on top gives excellent results, with fairly uniform growth down the plant and little subcanopy stem elongation.

When using Far Red in addition to Blue and Reds, by placing the Far Red on top with Reds and Blues, Far Red ratios are too large at the bottom of the sub canopy, but by adding Red and Blue at the bottom up can be used to lower the subcanopy Far Red ratios to desired levels.

Assuming that Far Red passes through the plant like an X-ray, works well, especially if there is plenty of good Far Red reflective material such as aluminum, but as a rule I start seeing results with bottom lit Red Incandescent Far Red using only half the amounts needed for top Far Red lighting, due to the filterring effect of the canopy on the Incandescent's contribution to the spectrum contains less Red to ballance out with the Far Red. With Far Red LEDs their is little difference between top and bottom lighting, but the affects of the top and bottom Red wattages are siginificant elongation/grow factors.

So, far as placement of Blues, Reds, and Far Reds, puting Far Reds at the top or bottom with Reds and Blues on top, with addtion Reds and Blue used mixed on the sides, top and bottom works well. If you isolate too much unmixed Red or Blue, it throws the plants ballance off and you get poorer results.

Blues and Reds on top with Far Reds, Blues and Reds underneath works well with little stem elongaton on the bottom and top of the canopy.

Ultimately Far Reds are best placed on top for better heat management (the more wattage on top the better (Heat rises. Go with that flow.)

I hope that coverred it.

Take care, Sal.
salmayo Reviewed by salmayo on . Selling 600w to go LED, need help with PAD/rauber technique I'm getting rid of my 600w HPS because I'm moving into a studio apartment and don't want super high electricity bills. Normally I can yield about .6-.7g/w. Because of the high cost of LED's I know I'm going to have to seriously downsize in terms of wattage so I want to maximize my yield potentials by manipulating the photoperiods. I'm going to be constructing a few of my own panels and was looking for input as to how I could successfully make a veg chamber and a flowering chamber both using the Rating: 5