Turning on the Grobo again 😁-CranecityCannabis

cant you just block out a few led diodes with some electric tape to lower the par level if there isnt a dimmer or a driver to lower it?


I think it’s more about the genetics than the light, in general. Some varieties just require less light to grow.

It’d probably be good to figure out which require more light and try to avoid them if that’s what happens.

Have seen plenty of grows that flower below the 2nd fan (and the 1st), but plenty of others that just don’t until they near or pass it. It’s mostly been autos that I’ve noticed stay short but some photos too.

@Jamminbear I just hit 2 weeks in flower on mine (same strain in 2 units, one with new light) with no pistils though I see the area they’ll come from starting to bulge like a calyx is coming. Didn’t seem to do that until they got closer to the 2nd fan, I started flower way down at the first fan. So same thing pretty much. Check out this fluffhead grow though, it’s flowering around the first fan.
:man_shrugging: :dna: :sun_with_face:


Yeah could be dependent on genetics, but after 10 years of growing, I have never seen current and modern varieties not show sign of flowering until day 30. There is something wrong with my light or the day I inititiated flowering from veg was inadequate in height. Like I said par level was at 150-200 which definitely confirms to me that plant did not have enough photon to trigger postal formation.


Par at canopy -1200 :joy::joy:
Temp Rez- initial 70f
EC - 1.5(1/2 distilled and 1/2 tap EC of 0.3)
PH 6.0-7
Power Si Bloom 1ml/G

Bloom ratios-
Jacks (5-12-26)A-3.6 g/g
Jacks (15-0-0)B 2.4 g/g
Epsom Salt - 1.2g/g
UcRoots- 2.5ml/G
Fulvic Acid -5ml/G
Hydroguard will be added 2 days
Tribus -0.5ml/G

The photos were taken a few days ago. Gawd I wish bought this light sooner. Definitely learn a lot about light management this run. Grobo lwd can definitively flower but u gotta make sure your canopy is within its distance to initiate flowering or else it’s going to take forever. This HLG 100 is a beast!!


Total day 130…after switching to the HLG it was smooth sailing from there. I’ll do a full write up soon. The bottom 2 were tester nugs pulled a week before. Cranecitygenetics is legit.


Awesome! Those nugs looks super tasty. That HLG is a beast and I am considering getting one for the grobo myself (thanks to you). Can I suggest tossing in a green co2 pad for your next grow you run with your HLG, this will allow your plant to get more out of your upgraded light. It seems with your higher environment temps (80f) and extra light, you would have the perfect conditions to add a CO2 pad and its inexpensive and the added co2 can probably take the grow to the next level.

I just recently got a co2 sensor discovered how bad the co2 flow in the grobo is (I also learned that your plant stops growing when co2 levels are 200 ppm and below) so these pads would help tremendously especially with a beast of a light like your hlg and I would love to see how much more yield you’ll get with it.

This is the co2 pad I’m talking about.


Congrats! Looks tasty!

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How long are those CO2 pads lasting per pad for you?

Sick stuff man! Those buds look awesome :slight_smile: tiny bit of purple in there… did you lower temps during flush to try to bring those out?

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I dont use the CO2 pads (I make my own CO2 brew, mushroom exhale bag and a DIY CO2 tank) but from what I read from the users is that they cut pieces of it and place it in their grow area and replace them for about a week or 2. I will be using the green pad along with a brew with my next grobo run.

There are only a few phases where you would want the CO2 bosst anyways which is during Veg, Early, and Mid Bloom. The rest, just make sure you have 400 or more co2 ppm is sufficient (same co2 as outdoors).

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Bud looks absolutely fire, great grow. I find myself very tempted to pick up that light :grimacing:. @Vicc I just added Co2 to my little op via an “Exhale” bag pretty impressive thus far, autopilot is reading around 1000 ppm on average. Not sure if it is being utilized however as the Grobo light may be a little less than what it needs.


That’s awesome! 1000 ppm is already 2.5x more than outdoors. I would boost up the light (Secondary light, as a side light since you have a tent) to get more out of the co2. The grobo light gives about 55-68k lux at the very top while with 1000 ppm, you should be able to hit around 85k lux or even more. Your exhale bag will ramp up even more as the mycelian grows in the bag. Since you have your grobo in your tent, I would turn off your exhaust and intake fans. Seal it (Keep temps between 78-84f, co2 requires it to be hotter to be effective) and only run the exhausts when the heat exceeds 84F. Your plant will enjoy the higher RH when the the temps are higher with the CO2 boost. She will also be able to handle higher nute levels with higher co2 levels.

You can gauge the light lux output by using a light meter phone app. The phone camera has really good light sensors, one of the best in the market.

Here is a chart used by CCH2O (makers of the UC products), it indicates the CO2 levels they use as part of their feeding chart:

They do not indicate any high temps ran with CO2 which most users would run when using high dosage of CO2 however.

Ed Rosenthal | Cannabis And CO2: Why Plants Suffer If They Don’t Get At Least A Minimum Amount Of CO2


@Vicc U think the Grobo would hold the additional CO2 and not just getting exhausted out? Grobo is definitely not a sealed room. I normally don’t add CO2 in tents either due to that same situation. I actually did add the the mycelium one time but it showed no appreciable difference in any kind. @pyromancy the color change on this is definitely genetics from my opinion. Temps was always a love 80 when the lights were on. Cranecity uses a lot of gelato in their crosses.

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Nice, they look like gelato buds for sure in a way… however, to release the anthocyanins in cannabis it needs to be triggered into lower night temps as far as I know… I don’t know of anyone else who has had purple weed from the Grobo as far as I’ve seen. People have grown Purple varieties too… hmm

Pretty cool either way. Maybe the spectrum of your LED you added had the right colors to bring out the purps a bit?

If you were getting daytime temps in the 80’s and then night time temps down in the low 70’s or even high 60’s that might be enough to trigger some “fall colors” paired with heavy purple genetics like Gelato


You can definatel seal the grobo if you wanted to. Also since the grobo vents upwards the co2 would move right though the canopy before exhausting out. I don’t think the grobo fans are strong enough to move the co2 out and co2 is heavier than air.

Also the mini fans blow the co2 upwards into the canopy. While having a fan at top blowing it back down could help mix the co2 into the canopy, I totally think its doable and going to make it a project for my next grobo run.

Even a mini exhale bag in the grobo would probably do wonders. I notice huge differences when I added the co2 and boosted up my lights. I also save on not needing to cool my tent down as often now with the co2 in there. The exhale bag alone gives me 800ppm in my event even aftet I have vented out all the co2, the passive co2 is at 800 with the bag, my brew adds an additional passive 200 ppm and the rest is just pumping co2 with my tank.

If you look at my grow, you can see how she started blowing up a week after I moved her into my tent, that’s when I started adding co2

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@Vicc what was the Par level at the height of your canopy. If CO2 works …hell yeah. The last week definite light stress was noticed with several leaves showing signs of clawing. I’m assuming u installed a CO2 sensor as well? @pyromancy I have a pulse lab installed in my Grobo. The last month the highs were 90s and the lows 75s. I have heard of the low temp triggering purple production. From my experience genetics plays a bigger part. If u look at this guy page. Most of his shiz turns black.

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I am using lux as my form of measurement. The large colas inside thr grobo is getting hit with 90k lux while the colas in the front close to my side light is getting 100k+ lux. No burns, light or heat stress. I am running temps up to 88 before cooling it back down. Not to mention that my colas in the front are only 10-12" from the mars hydro side light running at full blast. This light is made for a 5x5 room. Some growers go up to 94 but that sounds scary to me.

I am running 1600-2400 ppm at 77F. The fans and ac turns off when 77F hits, co2 turns on for 3 minutes, bonus lights turn on after. I let temps ramp up to 88F and let the AC cool it back down. At AC in, ppm is normally around 1200 then ac off, ppm is back to 800-900 before co2 tank turns back on.

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Just curious of why u chose the lux measurement vs PAR level @Vicc

My phone has a really good lux meter and there isn’t a need to spend money to get a par meter. I asked my grower friend who is an actual light specialist, he says using mole lux par are all OK

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