Ive spent a lot of time looking at different ways to improve the grow i work for. But what works for us might not be the right thing for everyone.
As for far reds: RN we are mainly suing 90cri diodes so we arent adding any far red during the day cycle, 90cri has a fair bit already. As for EOD far red: havent tried but its been fairly documented as positive, either up your yield or make your cycle faster. But id probably prefer recommending:
1: Use separate diodes rather than strips, you want even coverage or you may see some uneven stretching. Id recommend
@growlights Australia s Buddy system: it has very wide and even spread and is made up from a long atring of individual chips. You can also get a very efficient 660 photo red from them. It does cost a bit more than KB bit they are sealed, which helps keep them working well in a humid environment, and dont need any sinking.
2: 15 mins is almost allways too much, this advice only exist from analogue timers who couldnt do less than 15 mins. Theres a formula in the far red thread, basicly ots 3000-4000ppf total, which usually ends up as around 2-3 mins but depends on the total wattage of far red and efficiency.
On reds: i dont have a good answer on 660 (or 630) yet. Our grow with lights testing this is about to flipp to flower today, but its a bit away from where i am. But from what ive seen around the interwebs 660 should help with making the flower response stronger, faster budset and a bit more tricome. Some say they prefer adding 630; it has the increased growth of biomass but doesnt mess with the flowering hormones. Im not too sure, in about 3 months ill have at least some results to draw from. Our current line up is 660/630 half and half versus 660 pc reds (includes a lot of far red and 680-700nm) versus 630nm. Also running one side with extra 850nm IR.
Uv/blues/4000k: the thing some people miss out on is the relationship between blues, violets (420-430nm) and uv (365 and 285nm) and transpiration. Blues tend to open the stomata and help the plant with drinking more, which makes the grow altogether easier. If you looked around people trying leds for the first time youre bound to see people struggling with leaves bleaching or just poor plant stance, or just plants that wont thrive. Most of the time this has to do with the transpiration issues, a plant drinking without any infrared heating just has a hard time to keep up with the photosyntesis and especially in vegg or under low light or with co2 added. Although you can fix this with extra hot and humid climate its easier to fix it by adding some wide blue/violet/uv. But be carefull with 280nm as it is dangerous: for you and in large doses the plant. So really, if i was to make my favourite light as easy as possible: 2700k 90cri as base white and a wide blue channel containing both 420 and 365. The extra blue seems to make the grow easier, less finicky.
On another point: i just had the chance to try our latest cultivar, Glue Trap, in both indoor and out door version: the outdoor stone blows the indoor out of the water. Full facemelt. So there is definitely something in going beyond the normal led spectrum