Lighting Is there such a thing as too much LED light?

[Muddy]

You have left out one big item from your cost comparison of LEDs vs T5s, the cost of replacement bulbs. Normal fluoro bulbs start to loose efficiency fairly quickly and should be replaced at 6 months. I haven't looked at the Spectralux but have talked to Quantum about the replacement cycle on their Tri Phospurs. They recommend every 18 months. So over a comparable life cycle of LED vs T5, the T5 bulbs would need to be replaced 3 times (originals plus 2 replacement), adding about $330 to the cost of a 16 bulb T5. That brings the total cost of a Quantum 16 bulb system to $660 over it's life. That fixture will cover a 4' x 4' area. That same size area could be covered better with 3 Blackstar 240 watters or the equivalent. Cost for those would be about $800. So the difference isn't really that big, plus the added benefits of less heat and electricity with the LEDs.

I am in the process of switching from HIDs to t5ho.

At least in 2012, I do not agree with LEDs for growing because (compared to t5ho) they are way too expensive. Both LEDs and t5ho are equally capable of 70-100 lumens per watt but LEDs cost 3x the price (per watt) of t5ho. They are equally efficient, especially now that Spectralux t5ho lamps are so easily available.

But in three years, when LEDs are available for $2 per thousand lumens of LED .... then lets' take 'nuther look. (right now, roughly: t5hos = $5 per thousand lumens; HID = $4 per thousand lumens; LEDs = $12 per thousand l)

I agree that HID's are a pain in the ass - t5ho bulbs last for 20 gro seasons while HID (hps and mh) only really last for 1 or 2 gro seasons. Also, HIDs' are difficult to hide. The one thing I really like about them is that there is a 15 foot cord between the ballasts and the lamps - this makes it easy to either isolated the hot ballasts from the grow room (when I don't want all that heat) or (in Dec and Jan) place the ballasts in the gro room to keep it nice and toasty warm.

Compared to LEDs or t5ho, a thousand watts of HID (enough for 18 three gallon containers in my set up) is in fact fairly costly by the way - here (in Neo-Facist Amerikkka) for a 20/4 schedule, 1000w costs about $1.50 per day - a 1000w HID on 12/12 schedule costs 80 cents per day. If I used t5ho's instead, (for a 20/4) then I could grow 16 3 gal pots under t5ho's for $1/day.

But to answer your question: YES, there is such thing as too much light. Unless you are using a co2 system, what's the point in more than 6000 lumens per sq. foot??

Do not underestimate the heat produced by LEDs (and you cannot isolate a hot ballast outside your gro tent with an LED; same problem with t5s). But especially with cheap Chinese LEDs, lighting efficiency goes way down (and heat generations goes way up) as the LED gets old.

 

[Muddy]

I would also recommend 2 smaller LEDs over 1 big one. You will be able to keep them closer to the plants and can adjust them independently to compensate for differences in plant sizes. Unless you have a separate veg area, I would stay with the flowering spectrum ones. They will veg your plants fine and the added red of the flowering spectums will pay off with larger buds.

Hey Bonzo,

Thanks for the input! Even still I think I prefer LED. You can configure spectra, you can replace parts easily (if you find the proper company, but the good ones are great!), lifespan is lots longer, plus failure with a t5 is hazardous, with LED its perfectly manageable. Plus, electrical bill is still a deal breaker. Within a year it is payed for easy! And future upgrades is possible for a fraction of the cost, say replace an array with a specific diode, angle, etc.

It makes sense to buy 2 panels instead of 1. Regarding spectrum, would you go for 2x vsg & bloom, or 1 veg + 1 bloom? I wish there were more threads on spectrum for growing. I have come to my own conclusions, but still a bit shaky...

 

[agito]

also leds would be more efficient par Watt wise and penetration also and t5 lumens T5's should be bumped an additional 30% wattage wise as well

As a 400w hps will smash to pieces 400w of t5's but probs not 400w of led