Light distance, PAR and dimmer settings
I have a new SF-7000, Yeah!! 645 watts and the recommended height is 14"-16"/35-40cm for veg. The dimmer is recommend between 60%-90% for veg growth. I also got a PAR meter, to help complicate things. lol Then someone gave me a chart with the recommended PAR values for the proper DLI.
So these are the ingredients for my question. If I go by the manufactures recommendation for the distance and the dimmer setting, then the PAR is way high at the lowest rec dimmer setting, which is 60%.
But if I adjust for the recommended PAR to achieve the DLI, at the same hanging height I'm below the factory setting on the dimmer. So wtf?
So I'm trying the manufactures recommendations at the moment and I'll see what happens. I'm expecting light stress. There a difference of 200+PAR between where I had them and the recommended, I'm not change them that much at once. lol
Then while we're talking lights, which is more important, PAR with the light at a close distance or PAR with the light at a higher distance. So if I turn my light on full speed blast and then lower it to achieve PAR, is that the same as being at the recommended height but dimmed down?
@chillbert is a pretty bright guy when it come to interior illumination. lol Any and all thought's or comments. Thanks
I dont fuck around with any of this, i turn the light on, at a certain distance and my plants are always fine man. I feel as if it is easy to over complicate things in this game. Keep it simple, turn the light on 100% at around 18 inches above the plant and see what happens from there. I am sure they will be fine 😉 But thats just how i do my shit lol
I use my meter to set illumination to the level on this chart. Haven’t had any problems since I’ve had my meter and this chart so why change. Keepin it simple.
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Well here we have Yin and Yang, with @Macky at full speed blast and @Monkeydo taking the cautious approach. I'm working off the same chart as you Monkeydo, so that's where I'm coming from. I did turn the light up full blast and I was at 1100-1200 PAR for veg. I'm thinking that might be a little high. I'm at 750 PAR and that's above the chart recommendation, and I'm at 18" which is above the rec. I'll keep raising the PAR and see where they start smoking at. lol
This why I have two plants, so I can kill them both differently! LOL
Then while we're talking lights, which is more important, PAR with the light at a close distance or PAR with the light at a higher distance.
hi bro, agree with both mackys and monkeys points and approaches... you can deep dive as far as you like or keep it simple.. not all of the answers are there yet if u deep dive btw tech always will keep us needing a new something around the corner!
the way i see the Q above in terms of positives is : greater intensity with lowering the light vs more consistent footprint when you raise the light
645w will do a 5x5 or 4x4 but to go full blast at manufacturers recommendations you will need added co2 to allow the use of that extra light, as well as higher nutrition, more air to roots, etc (more of all the 8 other things a plant needs to make it maximise growth in its environment )
without supplementing co2 above 900/1000 par is a waste of energy that most plants cant use
i heard shane say a simple method to use... start the light at 50% and turn up a bit each day, watching the plants leaves, when they prey, youve hit the sweet spot, so long as other things in check..
guides are general i find and cultivars differ in how much light they can handle, but leaves never lie 😉
btw i run a thinkgrow 630w powerhouse etc etc
18" is fine at 75% for flower for all but some can take 100% while others cant without bleaching (nutes uptake cant keep up - prob easier with dwc / hydro /coco??)
i have some hierloom pure sativas atm that have grown into the light and touch the leds at 80% blast and theyre fine lmao (maybe equator strains like the sun 😉 )
your height can be decided by a compromise of how consistant footprint your wanting vs how big a footprint vs how much leccy u wanna save
if leccy were free i'd keep light at 100% and raise it up higher (like sun) but youd need a bigger footprint too
as it aint i run mine 80% for flower
i veg under migros from 50% to 80% power at 12" ish
Time to pop some more beans 😗
@woodi2 There is nothing like a brain teaser first thing in the morning (at least for me because I work nights).
I'm wondering if it would be possible to upgrade the potentiometer (dimmer) in your light. Most likely it will void the warranty. If you are interested in dimming multiple drivers with one dimmer, a specific potentiometer will be required for your application. I learned this from LED Gardner on YouTube.
I ordered some that dim all the way down to zero from 100, however, I never printed out my receipt and my order didn't come with a packing slip. Bummer.
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Thank @chillbert, great info. New quantum boards and gadgets and a fist full of info will make me ask these questions. My last lights were 310 watts and these are more so I'm trying to fine their sweet spot without too much damage. I think I have gained enough insight from everyone and a spoon full of each sounds like a good mix to me. I just keep trying to have a complete grow without to many battle scars. lol
Thanks everyone for your input.
@superc, thanks for the info man. Yeah the dimmer works well. I'm asking if people set their lights by PAR or by dimmer %. I don't have a problem (yet) with dimming down low, and I'm only controlling one light.
But the pic of that dimmer looks like my last dimmer, just lose. This is what makes me question how people are using them.
So with new boards and proper dimmers, lol, I afraid I'm gonna nuke'em! lol
So dependant on the overall intensity of the light I will either leave it on 100% and adjust height to suit desired par level or I will use a combo of both dimmer and height adjustment. I shoot for a par range of 250-450 as seedlings, 550-700 in veg and 750-1000+ in flower, once you get over that 900 par mark things can get dicey so reading the plant is the best port if call I find. But within those ranges you will usually be ok. If you get it just right you can leave your lights on full blast at a set height and the plants will grow into their par levels as they mature, but that's about as cowboy as my growing practices get lol
I feel like a, like a slice of butter... melting on top of a big-ol' pile of flapjacks... yeah.
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