I'm stumped!

[kenKgrow]

Grouchy, I just saw your comments from 2/8. Somehow I missed it when you posted. The chart is only for my auto grows. You are correct, over time, as yields have dropped, flowering and harvest times have accelerated. By "harvest time" I mean the age of the plant when I harvest. And no, I do not harvest early. The plants begin flowering earlier and finishing up earlier. Just when it looks like it's time to sit back and enjoy the stretch and watch the buds fatten up, they're done. By "done" I mean few viable leaves and the stigmas are mostly brown.

With the new HLG light, the plants look much healthier, but still tiny. Right now I have a plant growing that is supposed to reach over 100cm. It has 8 sets of leaves, it's flowering and is only 4" tall. It's 18" from the light. I tried having the light closer on a previous plant, but it burned it. Based on recent experience, I expect it wont even be a foot tall when it's done.

The one major factor that I haven't changed is humidity. I'm fixing that soon. bboyfromwayback suggested it eary in this thread. In the summer humidity is not a problem, but in the winter it get's too low. I bought a hygrometer recently and found that the humidity inside the tent is 27%. I should have that corrected by the end of the week (these problems have persisted in the summer , so it may not be the humidity level). The picture is at 16 days. It began flowering on day 18. When I first started with autos, they would be about a foot tall when they started flowering. Usually around day 21. I started another plant yesterday, so it should have the full benefit of correct humidity throughout it's life.

[kenKgrow]

gbauto, Thanks for those numbers. When I run them using my actual canopy of 3.75 sq ft times 50 watts of old-tech diodes = 187 watts with blurples. If I then take away 75 watts (just a guess) for using more efficient diodes I'm left with 112w. So the 95 watt HLG light may be undersized for this space. I should know soon.

I think the 135 watt HLG would be better for the canopy size, but the reason HLG steered me away from it was because I have so little height (about 50")

[YYCannabis]

Blurple lights are the worst. They truly are unreliable for calculating exactly how many watts of useable light is actually reaching the plant. The “UV diodes” suck a lot of power, but only deliver useable light at a very short distance. Every grower that uses blurple lights is truly wasting tons of electricity for minimal (if any) gain.

[bboyfromwayback]

Those are some important details Grouchy! Glad someone is paying attention to everything lol

[grouchyoldman]

Hi Ken,

Perhaps I'm reading your chart wrong, but there seems to be a sharp decrease in both Yield and "Harvest Time over time." They are positively correlated, in the parlance of data geeks. I'm not entirely sure what "Harvest Time" means, but if it relates to flowering 12/12 light schedule it might be a clue. Did you start harvesting early?

You also mentioned that you began with phototropic plants and switched to autos. If that is the case your decreased yield isn't surprising, those pesty AutoFlowers are quick to harvest but stingy when it comes to harvest yield. Could your Photo->Auto switch be the contributing factor? Was your grow #6 or #8 the switch to AutoFlower seeds?

I'm probably missing something here, but that's what jumps out to me.
Regards,

-Grouchy

[bboyfromwayback]

You got the bboy lol most do not

[kenKgrow]

Hi gbauto.
I did asked HLG about that. They said that their 135 watt fixture would be too much for this space and recommended that I go with the 95 watt Rspec, which is what I did. I guess if it's not enough I can add a second one.

[gbauto]

Interesting thread.
ken, you are working with approximately 5 sq ft of canopy.
The fixtures you're using state they consume about 88 watts with all leds running.
That's 176 watts of blurple leds.
I agree with the responses, you need more light.
A ball park estimate for your spoace to achieve adequate light intensity would be 50 watts/sq ft of canopy using old-tech diodes or HID.
That's250 watts for that space using blurples.
A fixture using more efficient diodes would equal that with 100 fewer watts.

[bboyfromwayback]

Grow 1 to 2 had a decent sized drop. Hopefully things start improving for you👍🏻

[kenKgrow]

Quick update:

I attached a bar graph showing the decrease in yield over 16 grows. I included the harvest time, which also shows a downward trend. All seeds were from FastBuds.

Current grow is at day 11. Too soon to tell if the new HLG light is making a difference.

[BR2K]

Thank you kenKgrow, you made me feel nuch better about my finicky LEC/CMH lights!

[SoOrbudgal]

Good for you and best of luck

[kenKgrow]

Thank you everyone for your knowledge and helpful suggestions.

I have taken the advice you gave and bought the HLG R-spec 100w. I have one seeding started and will put another in this weekend. I don't plan to change anything else so I can see if the lights were indeed the problem.

I'll update this thread once I have something to report.

[kenKgrow]

Yeah, that sounds familiar. I was surprised at how quickly things dropped off.

[kenKgrow]

Thanks dilvish, Yes, I grow from seed. I've replaced my light, so I will go through a grow with no other changes to see if light is the problem. If I'm still not happy I will change some of the things you have mentioned.