Photoperiod Gorilla Glue #4 & White Widow

[tronN00dles]

How do you feel about your work so far?

It is beautiful so far. Really perfect looking. Genetics seem to be excellent.

Many thanks!

Yeah I'm pretty pleased with this grow. Definitely the smoothest so far. I've only been at this for ~2-3 years or so and I'm still very much trying to figure shit out. For some context, this will be my sixth harvest. I did 2 auto runs in soil, then 2 auto runs in Pro-Mix HP, then this is my second photo run in coco. Plus several failed attempts in between, of course.

In terms of my actual growing strategy, it's very much "by numbers", i.e., figure out target DLI/PPFD, pH, ppm/EC, VPD, etc., and try my best to reach those targets. As for this particular grow\, here are the major things I've done this time but not the past 5 times, at least not consistently:

• Preventative fungus gnat and pest treatment (nemotodes, BTI), sterilizing resevoir between changes with peroxide, etc.
• automatic irrigation and drain
• more accurate instruments (InkBird humidity controller differs substantially than the AC Infinity unit I was using before. It seems for those last 5 grows, my tent was substantially dryer than I thought; cheap pH pens do more harm than good, etc)
• Knowing best practices for the medium. Coco isn't soil and shouldn't be treated as such, and vice versa. When I first started, I was treating organic soil closer to how soilless mediums should be treated, at least in terms of using liquid fertilizers and watering techniques.

In terms of regrets, I do wish I had of taken your advice and removed more of the growth that was thinner than a pencil. It is a little crowded in the tent, and I think next time I'll shoot for fewer, bigger buds, rather than more of the smaller ones. But oh well.

Speaking of next time, I think I'm going to take a break from coco after this go and circle back to the Pro-Mix HP. The coco is a hell of a lot of work, at least in terms of how much water I'm going through and the frequency of mixing nutes, etc. We'll see how that goes!

tron

 

[Death The Cultivator]

Many thanks!

Yeah I'm pretty pleased with this grow. Definitely the smoothest so far. I've only been at this for ~2-3 years or so and I'm still very much trying to figure shit out. For some context, this will be my sixth harvest. I did 2 auto runs in soil, then 2 auto runs in Pro-Mix HP, then this is my second photo run in coco. Plus several failed attempts in between, of course.

In terms of my actual growing strategy, it's very much "by numbers", i.e., figure out target DLI/PPFD, pH, ppm/EC, VPD, etc., and try my best to reach those targets. As for this particular grow\, here are the major things I've done this time but not the past 5 times, at least not consistently:

• Preventative fungus gnat and pest treatment (nemotodes, BTI), sterilizing resevoir between changes with peroxide, etc.
• automatic irrigation and drain
• more accurate instruments (InkBird humidity controller differs substantially than the AC Infinity unit I was using before. It seems for those last 5 grows, my tent was substantially dryer than I thought; cheap pH pens do more harm than good, etc)
• Knowing best practices for the medium. Coco isn't soil and shouldn't be treated as such, and vice versa. When I first started, I was treating organic soil closer to how soilless mediums should be treated, at least in terms of using liquid fertilizers and watering techniques.

In terms of regrets, I do wish I had of taken your advice and removed more of the growth that was thinner than a pencil. It is a little crowded in the tent, and I think next time I'll shoot for fewer, bigger buds, rather than more of the smaller ones. But oh well.

Speaking of next time, I think I'm going to take a break from coco after this go and circle back to the Pro-Mix HP. The coco is a hell of a lot of work, at least in terms of how much water I'm going through and the frequency of mixing nutes, etc. We'll see how that goes!

tron

It's a feat of beauty for the amount of experience you have. I believe your approach is consistent and similar to mine, being able to apply the theoretical and see results. There's nothing wrong with being technical because scientist have spent years accumulating this knowledge for general betterment and when done properly is a benefit.

Coco works very well but with typical drain to waste methods it's a damn time sink. I think it requires a rather large amount of space to keep the workload down. A 55 gallon premixed with a secondary 55 means way less mixing but no matter what Coco uses a lot of water with drain to waste. I prefer sub irrigation as the top layer doesn't promote pest, root growth is optimized, and less water is used. Ideally I would run 4x4 tables with 70 gallon reservoirs for a flood and drain just to save water.

I think it was a damn good run though and finding what works best for you is the path to continued success. Granulated Rockwool is another choice that is rarely talked about

GRODAN GRO-WOOL, 45 lb

Massachusetts' Indoor Garden Experts. Start a natural organic garden at home, grow herbs, veggies, anything you want. Get started today!

www.nehydro.com

 

[tronN00dles]

A few more pics. Buds are forming nicely and things are getting STICKY and STINKY lol.

And just like clockwork, I have some burnt tips appearing. I've never not been able to get burnt tips around this stage. It seems pretty minor so I'm not too concerned, but it's a bit annoying. Everything points to excess nutes, but I'm only feeding around ~550ppm / 1.1EC. pH at 5.9-6.1. Lights at ~800 PPFD at the upper-most bud sites, and VPD around 1.4.
Is there a secret to avoiding burnt tips? Because so far, I haven't found it!

tron

 

[tronN00dles]

Beginning of Week 6 since pistils (Week 7 since flip to 12/12)

• Lights at 880PPFD at highest/brightest point (currently drawing 271W ac from wall)
• pH 5.8-6.2
• ppm = 550 (1.1ec)

I've made a VPD target adjustment due to burnt tips at low ppms: I've been assuming a 2 deg C difference between leaf temps and ambient temps as per www.vpdchart.com. However, I think 1 deg is a safer number, otherwise, you permit dryer conditions in the tent. Long story short, I'm going to bump the humidity up in my tent a smidge.

Latest temp/RH targets assuming leaves are 1 deg C cooler than air temp:

• 23.5-24.5 deg C
• 45-49% RH

I'm thinking another 3 weeks until harvest.

Thanks for reading

tron

 

[Death The Cultivator]

Beginning of Week 6 since pistils (Week 7 since flip to 12/12)

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• Lights at 880PPFD at highest/brightest point (currently drawing 271W ac from wall)
• pH 5.8-6.2
• ppm = 550 (1.1ec)

I've made a VPD target adjustment due to burnt tips at low ppms: I've been assuming a 2 deg C difference between leaf temps and ambient temps as per www.vpdchart.com. However, I think 1 deg is a safer number, otherwise, you permit dryer conditions in the tent. Long story short, I'm going to bump the humidity up in my tent a smidge.

Latest temp/RH targets assuming leaves are 1 deg C cooler than air temp:

• 23.5-24.5 deg C
• 45-49% RH

I'm thinking another 3 weeks until harvest.

Thanks for reading

tron

There's your problem. Below 50% is too low but bumping your temps to ~77f and 53-55% rh would be closer to what cannabis prefers in general. Definitely too dry, you'll need an IR thermometer in the future to perfectly dial in VPD, they do look really good though.

 

[tronN00dles]

 

[tronN00dles]

Beginning of Week 7 since pistils (Week 8 since flip to 12/12)
Well folks, looks like we're on the home stretch

I'm starting 'ripening' nutrients today (GH Ripen) and I'm thinking I have 2 weeks until chop time.

I'm happy to report the burnt tips aren't getting any worse - thanks to @Death The Cultivator for the humidity recommendation. I'm now keeping it around 49-55% and the plants seem happier.

Numbers update:

Lighting

• max PPFD around 920, for an upper DLI limit of 40 at 12/12. LEDs drawing a combined 310W, around 16" from canopy.

Nutrients:

• GH Flora Series Week 7 "light" mix at ~85% (Armor Si, CalMag at 2.3mL/gal, Micro, Grow, Bloom, Floralicious Plus, Ripen)
• ppm around 550 or 1.1ec (500 from nutes plus 50 starting tap water)
• fertigating 5x a day
• pH around 5.8-6.3

Environment:

• Temp target: 24.5C to 25.5C
• Humidity target: 50-54%
• The above gives me a VPD range of 1.2-1.4 accounting for a +/- 1% RH over/undershoot.

A big lesson I've learned from this grow is the importance of humidity, even during flower. My problem was I was targeting 1.4-1.6 VPD for late flower. vpdchart.com recommend 1.2 - 1.6 for mid/late flower. I was trying to aim for 1.2 during mid flower with the intention of gradually raising it to 1.6 for late flower. This approach gave me burnt tips. The better thing to do is treat that 1.6 as an extreme upper limit and to avoid it, rather than trying to get there. I also read another source that recommended ensuring VPD stays below 1.5 and above 1.1 during flower. This is how I ended up with my 1.2-1.4 target, and it seems to be working.

A tip for people who enjoy control systems - I have the best luck at controlling VPD by keeping the temperature bandwidth tight, and humidity a little looser. I can get much big humidity swings in my tent, but I can keep temperature pretty stable. However, if I have a large temperature bandwidth, it's difficult to control the range of humidities that would permit certain VPD's across all temperatures. Long story short, I seem to have the best luck keeping my temperature bandwidth small (1 degree), and my humidity bandwidth looser (4-6%).

Anyway, enough jibber jabber. Here's some pictures...

 

[tronN00dles]

A few pics….

~10ish days until harvest, probably.

 

[Talonxracer]

Some very nice looking girls you have there!

 

[tronN00dles]

Home stretch....

Starting to show some fall colors

Harvesting sometime next week I'd say...