Main Cabinet Evolution

Here is my main grow cabinet, shown just after receiving a bunch of work. This pic is about 60 days old, & was taken the first day that I put it back into action. I’ve made a few more changes & adjustments since then, but here is how it was when I started using it after performing most of the upgrades:

It’s a built-in closet with internal dimensions of 24" deep, 28" wide, & 84" high. Very similar to my old Mills Pride C-13, but with more head-room. I’ve grown in this space a number of times before, & there were some issues that I wanted to address. Some of the main improvements shown here are as follows:
-Added 1/2" R3 foamboard insulation to everything but the door.
-Added 250w electric panel heater to door.
-Relocated charcoal filter & fan from front left corner, to just below the ceiling. Fan is moved out of the cab & into the adjoining storage cab.
-Removed existing shelf near top of grow space to make room for charcoal filter.
-Caulked seams, applied fresh latex sealing primer & flat white latex ceiling paint.
-Upgraded to LED light from HID light. ( Ignore the pink insulation “stilts” on the light, I accidentally installed the eyehooks in the ceiling a half-inch off-center to the left, & am pushing it over with the “stilts” to center it, until these plants are done. I will probably do slider rails in the same style as my mini cab, instead of single eye-hooks, when I re-do it.)
-Upgraded to thermostatically-controlled day/night fan controller (had been using a dial-a-temp), added the DIY humidifier & controller, oscillating fan below the canopy, upgraded the surge protector, upgraded from mechanical to digital timers, added two bluetooth thermometer/hydrometers - one near the canopy, one near the ceiling.
-Added a new 5-gallon bucket setup, each with an internal aerated circulation pump & also a 10" air bubble stick going across the bottom. Old setup was a 4 gallon tote with just the aerated circ. pump. (Note- this cab is best at running one bucket & one plant, but I want to test these new buckets out, & I want to try some training techniques & had some other reasons to run two buckets & four plants anyway. In the future I’ll do one-plant/one-bucket with the 5-gallon, & I also found a 7.5 gallon tote that I want to try.)

Original air intake filter/ light-trap, unchanged:

Original Vortex VTX400 in new location:

Original lights on stand-by:

Pump & manifold for air bubble wands :

Controller & plugs for DIY humidifier. Still need to vac those leaves out of there :

These plants spent too long in 4" nursery pots in my veg cab as I was working on this cab, & were root-bound & a bit nute-locked by the time it was ready. I unraveled the roots & pruned ~75% of the roots off when moving them into the net pots. The one in the front left had really fine roots, & more than I wanted just tore off as I was attempting to unravel them to prune them, so she got a little shocked & clamped down for about 5 days. I wanted to try some LST training clips, so I ordered some, & made my own out of plastic until they showed up.

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looks good to me

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Thank you!

A couple days later, I installed my ‘new’ larger screen.

This screen is cobbled together from a couple other frames, & consists of pieces of my original frame that I’ve been using since my first grow years ago. I was originally able to move it straight from my C-13 into this space with no mods, & it fit perfectly. Now I had to reduce the width by 1" after adding the insulation. I was also able to increase the depth by about 6", since my filter was no longer in the front corner. So even though I lost a bit of overall box footprint due to adding the insulation, I gained a lot of screen space by moving the filter. The old screen size actually worked pretty well with the HID light due to its footprint having a sharp cutoff beyond 18" front-to-back anyway. The new LED has better overall coverage, so hopefully it can utilize the bigger screen. Fresh wire screen was installed, once I had cobbled together the bigger frame.
I also moved both of my sensor wires to a single hanging cable, just to clean things up a little bit. I’m still fiddling around with sensor placement to this day, so you’ll see them occasionally moving around in the pics.
The oscillating fan was moved to the ‘empty paint can stand’, & the humidifier moved to the ‘stack of insulation stand’.

The light is set to 25% power on the veg channel, pulling about 40w from the wall, & the plants are seeing around 400 ppfd (iirc) at the height in these pics.

I had topped these plants when installing my home-made LST clips, & I figured I’d use the screen to do some ‘top-down’ LST training:

About five days into running this cab, I raised the light & turned up the veg spectrum power to 50% (light pulled 80w from the wall). I maintained around the same ppfd, but with more even coverage.

I also replaced the bungee cord with a chain to hang the carbon filter, & added a 4" A/C axial fan & triac speed controller, as I noticed a ‘big’ difference in heat & humidity between the top & canopy levels of the cabinet. Due to the springtime ambient conditions at the time & the fact that the light was turned down & not making a bunch of heat, & the exhaust fan was not running very often, the box was actually running cooler & more humid at the top compared to the canopy-level, & a couple times when it got cool at night, it hit the dew-point at the top of the cab & I would get some condensation starting to build up on the screws holding the insulation to the walls (thermal bridging - the rear & right walls of my cab are exterior walls). The fan helped a little with the humidity build-up, but setting my humidifier control to a drier target helped the most, if I knew it was going to be a warm day/ cool night type of deal. The fan does help to even out temps & humidity from top to bottom, so it stayed. Once this grow is done, I’ll go back in there & make some sort of proper stand or hanger for it. It looks a little janky right now, but it is safe & good enough for now.

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Four days later & my LST clips arrived, so I installed them. Also started to prune a bit. Accidentally broke a branch off a couple days earlier, oops.

Checked my notes & just to correct myself, the plants were seeing 330 ppfd with the light lowered & set to 25% power. Then when I raised it & turned it up to 50%, they were seeing 400ppfd.

Three days later:

Day after that:



I’ve never pruned this aggressively before. But this should help me to see what I am doing & to get everything to the screen at around the same time.
I also raised the net pots out of the holes & pruned off all of the roots hanging further than an inch below the bottoms of the pots.

Five days later & nearly all of the main tops have reached the screen. I adjusted the light to 12" above the frame & increased the power to 75% on the veg spectrum. I also made sunshields for the temp sensor for my fan controller & the Thermpro bluetooth thermostat/ hydrometer sender. Probably should add one to the humidifier controller sensor too.

Also one thing I forgot to point out in my last post was that I had removed the LST clips at that time, only because it was time to remove them. Also you can see how the trunks grew differently around my two different styles of DIY clips. The ones in the back were made from plastic shaped like a C-channel, & the trunks stayed in the channel & are more narrow. The ones up front were ‘flat-C’ shapes that I made out of pvc pipe, & the trunks were able to grow out more.

Nearly the same pic as above, but around 12 hours later. I wanted to see the whole screen, so I could make a plan.

Plant placement isn’t ideal. They are set a little far back due to space limitations, but I saw that ahead of time & am not too worried.
SCROG plan:

With the light at 75% veg spectrum power & 12" above the screen, I took a rough edge-to-edge PAR map at screen height, with the door closed :
375 500 545 530 410
480 650 666 650 490
365 475 536 475 365
Also I don’t think I noted it, but I run 24/0 in veg.

Another four days & it started to need regular pruning. Res were changed a day earlier & PPM was raised by 30%, so the leaves were reacting a little, no worries:

I kept training & pruning for the next five days to get to here:

These next few are five thru seven days later, getting ready to flip:

I also cleaned up the humidity sensor wiring & moved the sensor to see how it would work in a different spot, & added an oscillating fan to the wall. The fan looked like a piece of junk so I bought one to try, & if it seemed like it was going to be OK, I’d get another for the other side. It’s powered through a USB 5V DC + 120v AC power wart, which is plugged into one of the cycle timers. I have the oscillating fan under the canopy running off of the wart also.

The light has been plugged into the other timer in preparation for the first dark period. It is still at 75% veg spectrum only, pulling 120w at the plug. This is too dim for enough dli at 12/12, but there was some uncharacteristically warm weather approaching, & I was behind on my air conditioner situation for a few days.

After four or five days into flowering, I realized that the humidifier could be turned off/ removed. In its place I added a second oscillating fan below the canopy. I also went with a second oscillating ‘wall’ fan. All oscillating fans are plugged into the wart on the cycle timer.

At six days into flowering, my A/C situation was rectified & the heat-wave was down anyway, so I turned up the veg spectrum to 100%, & according to my notes I set the light height to 14 3/4 inches above the canopy, & my PPFD in the center was 777. At 100% veg spectrum, the light was pulling 160w from the plug.

A week into flowering (the next day), I turned on the bloom spectrum & set it to 25%. This added 15 watts to the lights draw, IIRC.

A couple days later & I turned up the bloom spectrum to 50% (light is now drawing 190w). This is a little early for 50% bloom spectrum according to the light manufacturer (they suggest going to 50% at the start of the second week of 12/12), but I felt like I needed a little more PPFD.


Also, I added some vent-holes to the sunshade on my Thermpro bluetooth.

Oops this should say third week & not second week.
Here is how the manufacturer suggests implementing their bloom spectrum:
Week 1 (of flowering) 0%, Wk2/3 25%, Wk3/4 50%, Wk5/6 75% Wk 7/8 100%
I started ramping it up to 50% a little earlier, at the risk of exacerbating stretch.

Anyway, here they are after two weeks of flowering & a res change to start setting the nutes to a flowering ratio.


Here they are five days later:


I’d been having some gnats & other bugs flying around in there, hiding & munching on my leaves, so I added the yellow stickies. Luckily they stayed out of the roots thanks to SM-90. Gnat source turned out to be the soil of a houseplant in the room, so I treated the houseplant directly with skeeter dust.

A few hours later…

This was the result of some major defoliation for the beginning of Week 4. This is more defoliation than I have done in past grows where I would strip up to the top few nodes & leave most of the fans up top, & then just tuck them down as needed, & remove some as needed. This time I tried the method of taking most of the fans but leaving most of the nodes. I also left some with more fans, including the one in the front left corner with tape holding it together. (I had snapped that one nearly completely off a few days earlier when doing some stem-crushing/ “vertical super-cropping”, which I did to most of the early taller stalks throughout the box, as well as most of the stalks across the front row.) I also left some short stalks to observe what they did in this light. Anyway, I’ll say ahead of time that I probably would have been better off doing what I had been doing originally, but I’ll also probably be utilizing more defoliation in the future than I had been doing. I decided nearly a couple weeks afterwards that leaving the lower buds didn’t look like they were going to work out. But I think someone with a more powerful light & probably more elbow-room could benefit from leaving most/ all of the nodes.

For this week I raised the light to 21" above the screen & turned up the red spectrum channel to 75%, drawing 205w from the plug.

I made a rough PPFD map above the tops. The door was open so the numbers are lower than they would be with it shut, especially along the front edge. The canopy is uneven. The tallest top in the middle is 9" from the light, & the tallest tops on the left & right are anywhere from 7" to 9" from the light.
470 760 900 770 475
640 1000 950 825 650
715 1100 1200 950 675
560 770 850 700 575
385 545 575 470 325

During the week I started to notice that my ‘lights-out’ humidity was getting very high. The fan would reach the temp setpoint, shut off & sit. I could set the target artificially low & have it always run full speed, but I don’t want to do that. Instead I hooked up my spare 4" fan inline with the existing fan (in order to utilize the existing carbon filter), plugged the new fan into a timer so it wouldn’t run during lights-on, & plugged that into my humidity controller ‘dehumidify’ work plug. I put the lights-out setpoint of the temperature-controlled fan to an emergency setpoint higher than its lights-on setpoint, in order to keep it off during lights-out, unless there are higher temps than normal.
This is actually working well so far.


I will say that running fans inline like this is ‘wrong’ or at best a band-aid, because they will always see each as an obstruction & steal efficiency from the other - even when both might be running. In terms of airflow, this is just a bad as putting one fan on the intake & one fan on the exhaust. Maybe I’ll put it in parallel with a second filter once the cab is empty again.

Week 5 begins.

I did a res change & nute ratio change to increase the flowering nutes. I turned the bloom spectrum up to 100%, & raised the light to 22" above the screen. The light is drawing 220w. PPFD in the center above the top is around 1200, & my notes say that the PPFD map above the tops is roughly similar to the week before. It’s a little hard to measure with the plants in there.
Center top is 7" from light. Tops on the left are 5 1/2" to 7" from light. Tops on the right are 6" to 9" from light.
The stretch slowed down, but still stretched a bit throughout most of the week, maybe 1/2" a day.

This was an interesting week. I spent a lot of time trying to dial in the box & my environment as ambient temps are rising, trying to get lights-on temps & leaf temps & VPD in a good range. I’d been running lights-on during the night, & lights-off during the day. But after a couple days I realized that ambient humidity is working against me this way & maybe I’m doing this backwards. Maybe I’d be better-off with lights-out at night, & lights-on during the day. So I gave them a 24 hour dark period to flip the schedule, & continued dialing it in. This seemed to work well, too well in fact. I did another big defoliation & pruning after deciding that a lot of the lower stuff needed to go. Not paying attention to the low humidity while the door was open for a few hours during the day as I was pruning showed them as low as 40% RH. If the door had been closed, it would have been moving between probably 55 & 70% as the temp fan would have been regulating the temp with a gentle air exchange. So they showed a little stress from no light, & then the low humidity & probably the chop, & then they got high light & heat from me “dialing things in” & showing them a little too much heat for a few hours. Plus some of the tops continued to stretch a bit & are very close to the light. I raised the light a couple clicks again this week, but decided to let the closest tops sit 2.5" to 3" away to see how they will react as I have not yet seen LED light stress in person. Sure have seen HID light stress though. If they stretch closer again, I’ll raise the light some more. I might be causing it by having the light so close. But it seemed to not have stretched last night or today, so I’m hoping that it is done. Right now some of the closest leaves are reaching & tacoing a little bit. The plants on the left have been stretching the most & are closest to the light. The plants on the right are lower, but still seem to be doing OK despite having less light. I left more nodes on them when I did my last-minute call to clean out a lot of the bottom nodes & branches this week.
I also used some training wire to position some of the stalks & to push them away from the walls.
These are from earlier today, & the full-box pic is from the day before:

I guess it’s starting to look a little crazy in there, but just keep in mind that this is a shakedown run. Next week I’ll probably clear out some of the last remaining lower fans & any low stuff that might start to look ‘off’, especially if I have to continue to raise the light.

Today is the first day of Week 7, & I’m thinking that these will need 10 weeks, maybe 11. Last week was a little rough on the plants. The ones on the left kept creeping up 1/4" every couple days, so I kept raising the light a couple clicks at a time. This was helping to keep them from frying worse than they had already, but I started to worry about the lower bud sites not getting enough light, particularly on the plants on the right with their shorter tighter structures. Last week when they all saw some stresses, the ‘Front Left’ plant got some leaf taco & edge curl further down the canopy than the other plants, & they might not relax. Some of those tacoed/ rolled leaves on the front left plant are starting to fill up with water again, some are still pretty deflated but haven’t crisped out or died yet, so maybe she will just be slow rather than stunted. All of the plants had some leaf curl on their tops last week, but the others have mostly recovered. I think the front-left one she is having trouble adapting to the lower daytime humidity during daytime 'lights-on" compared to evening ‘lights-on’. She might have been fine if I had started “lights on” during the day in the first place, or had left it alone. But the others seem to be rebounding from the stresses of last week, & it can be a lot easier for me to drop the humidity during the day if ambient conditions are there, so I don’t really mind having moved to ‘daytime lights-on’.

Decided to call an audible:

Installed it yesterday:

Barely fits across 27.5", & it sits 1/2" offset to the right due to how the cords sit. I’d like to install some 90deg low-profile adapters or 90deg cords there. I think it’s also slightly more towards the back wall, but fine for now.


This light at 75% gives me more even coverage at a high-enough PPFD, while being further away from the plant than the Kind was. At 75% it runs at about 15w or 20w more than the Kind did at 100%, & there are now more surfaces giving off heat, so it’s putting just a little more heat into the box & at a faster rate than the Kind was. I turned the A/C down a couple degrees, & I relocated my ‘lights-off humidity extraction fan’ from in-line with to parallel to my main exhaust fan, & gave it its own carbon filter (grabbed it out of my Mini Cab). I added some extra felt to choke it down to reduce any ‘recycled’ hot wet airflow coming back through the humidity fan when the main exhaust fan is running (Main fan can now see the humidity fan as an ‘intake’ & vice-versa, which is not ideal.). The humidity fan doesn’t need to flow that much to do its job anyway, so I choked it down with a lot of felt. Once the box is empty, I’ll probably relocate the black humidity fan into the actual box& slide the carbon filter over to the right, just to open up a little more room in front of the main exhaust.
Next will be to open up my intake area & make my light trap/ intake filter bigger by maybe 2x, although I’m going to try & put that off until the box is empty again. I may eventually go to a stronger main exhaust fan if necessary. For now I’ve regained a little flow by relocating the humidity fan, & I’ll just keep the A/C down colder than I want to.

Also, I relocated the upper canopy oscillating fans to the back wall & the door, so the ballast wouldn’t be in the way of their airflow down to the canopy.

The Kind will be used as a Veg light, & maybe as a finishing light for screens with a shorter & more even canopy, since it has the UVA diodes. Besides not having UVA, the only other tricks the SQ300 can’t do that the Kind can would be the remote-able ballast, & the split spectrum controls.

It was bugging me that I was having any recirculation between the two exhaust fans, so I made some changes & added flappers to both exhaust exits.

VTX400 running. The flapper on the black fan is being pulled closed & sealing the exhaust, preventing recirculation of the exhaust:

Inside, I backtracked & removed most of the felt padding from the new filter, added an eyehook & hung it up with zip-ties. I’ll add a piece of safety wire. I also removed the clamps & coupler so it would fit across without having to move eyehooks & chains etc. The fan plugs directly into the filter & is sealed from the other side with some adhesive foam stuck to the fan.

If anyone was wondering why I have different layers of filtering on the big carbon filter, it’s a multi-stage choke to even out the airflow through the carbon. Otherwise the fan will pull 90% of the air through the first 1/4 of the filter. The carbon hopper portion used to be a foot longer when I used to run it vertically, which made it even more necessary.

I’ll wait for tonight to see how the other fan runs. I might have to improve the hinge on the VTX400 flapper. It rests at around 30deg open when the fan shuts off, & the black fan might not be able to pull it shut, we will see.

‘Lights-off anti-humidity fan’ running & pulling the vtx400 flapper shut with no problems. =)

Hotter weather is approaching & I had some time over the weekend, so I figured I’d try to find zero static pressure & see if I could take some work off of my air conditioner, or at least get the box moving air through it as efficiently as possible with the current main fan.
I dropped a piece of scrap-wood behind the wall to protect the electrical cables, & added two more 4" holes to the right of the two original holes.

Then I cut out the remaining material:

Then I increased the intake hole on the other side to around 1/3 larger than the original size, & put a bigger cover over it. The cuts are pretty bad, I was just trying to get it done & don’t have the proper tools.

These two changes brought the box to just under zero static pressure with the main exhaust fan running at 100%, but only without my light-trap/ filter box in front of the hole.
So I sectioned the box to widen it with the white foam-board, & made a couple other changes internally to free up some air-flow, & tripled the intake area covered by the filter (black speaker grille fabric). The only downgrade is that it is not quite as light-proof as it had been, but I may be able to fix that later without stealing CFM. I’m probably going to make another one of these once I’m happy with it/ once it’s as good as it’s going to get, since this one is pretty cobbled together now & more of a working prototype at this point.

These changes then put the box under just a bit more negative pressure with the main fan at full tilt. When the lights are out & the anti-humidity fan is running, it was actually at nearly zero static pressure & the flapper was bouncing against the main fan, so I added a foam collar & that solved that. (The main fan is spooling down in the pic so the flapper is open, but it will draw tight against the tan foam strip when the fan is off & the black fan is running during lights-out.)

It’s pretty hot today, about 2 degrees under the last heat wave, & I’ve been able to physically raise the main fan temp sensor nearly even with the top of the tallest bud, which is still 5" away from the light (stopped stretching finally). I’ve been able to lower the max temp target of the main exhaust fan from 85f to 84f, & I’ve been able to raise the temp target of my air conditioner one degree. The main fan is regulating the temp at the canopy between 83f & 84f as it turns on & off. If it starts chasing & running constantly then I would have to increase the target temp for the exhaust fan, &/ or turn down the air conditioner again. But I know that the flow through the box is about as good as it’s going to get unless I want to upgrade the fan to more CFM, & then I’d probably have to add more intake to support it & still have it running just under zero static pressure. For now the VTX400 & the added flow seems to be doing OK. Max leaf surface temps fell about 2f but still seem good, 78-80f on the tops of the tallest buds, anywhere from 78 to 72 across the rest of the top of the uneven canopy, & 70f on the bottom-most leaves. For a little headroom I’m seeing if I can lower the max temp of the box at the canopy from 85 to around 84 without the fan ‘running away’. Because while it is hot out now, it can get a lot hotter. Chances are when really hot heat shows up, I’ll be lowering the A/C by a degree or more anyway.
These buds could be doing better, could be doing worse. They are growing a little weirdly due to the stresses & changes going on around them. I haven’t been defoliating much at all since the one plant started acting up, but I may start at least a little bit for the next week, & then maybe do a big one for the final couple weeks. One thing is I think I could have switched to my next flowering ratio, reduction of Si & CalMag, & addition of Epsom Salt last week instead of in a couple days from now when I have the res-change scheduled.

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‘Week 8’ started today. I changed the res for a scheduled ratio change. This should be the last res change, but there is still one more ratio change on the nute schedule, & I’ll just mix my add-back to that & it should at least be moving towards it over the next couple weeks. Now I’m thinking that these might all be done by 10 weeks, but I will have to start watching them. I’m probably not going to do much of a flush if at all, but will taper down PPM over the next three weeks. I’m behind on the ratio change schedule by a week or two, but next time should be better. They probably got too much nitrogen over the past couple weeks. Plus some of the leaves on the edges looked like they had probably been loading up on it, since they were in more shade until I put the bigger light in. The ‘Front Right’ plant in particular fluffed out & started foxtailing towards the light about three days after seeing the new light. Most spots going from the edges to about 6 or 8" inboard were seeing more PPFD with the new light so I’m not entirely surprised, but I didn’t expect it to happen there based on how low those buds are. Not going to worry about it. This is a shakedown run, & it was worth it to get that light in there.

Still haven’t defoliated much, been watching for any issues though. Some of the lower buds on the Left plants are starting to purp up a little.


Week 9 begins today, & it’s been really hot for the past few days, & going to get a little worse over the next few. Not as hot as it might possibly get around here, but not far off. Luckily the box is not breaking a sweat & it still has headroom to cycle at lower temps than I have it set to without ‘running away’. But I did some testing & tuning while checking this, & was able to dial it in a little better in terms of hitting a slightly better range of leaf VPD numbers. It seems better off leaf VPD-wise letting it run up to 85 max & also setting the A/C back down a degree. During lights-on, this gave me slightly lower humidity in the lungroom & the box, as well as higher leaf surface temperatures overall once they heat-soaked, & I ended up with a better range of VPD numbers as it moved thorough the temp ranges compared to the previous settings. It’s interesting to see how much heat-soak gets knocked off of the leaves when the fan is done exhausting, & then how much they have soaked back up when the fan is just about to turn on again. These numbers were a little surprising & some were out of range of all of the VPD charts I have seen. The online VPD calculator made it possible to work within the range of my leaf temps & to see what the leaf VPD was doing while avoiding any confusion from charts suffering from lack of data or mystery offsets, & the pyrometer is staying in my box of weed-growing tools, even though ultimately I don’t have really great control over my humidity levels. During lights-off (actual night-time), I’m usually at the mercy of rising ambient humidity, even if I shut off the A/C to let the temps rise. For the past couple of days I’ve been letting the A/C run during lights-off to help keep humidity down & also to give the plants cooler air since they are starting to finish. Not sure this is a good idea, the first day when I ran it but a little warmer than during the day the humidity crept up anyway. Last night I let it run cooler than the night before, & humidity was kept lower, but the cooler temps have me watching for any mold/ bud-rot problems especially at the bottom canopies of the plants on the right. One thing I’ve been doing is blending the air from the other room with the other box & other A/C in it, since it is generally less humid in that room. I think one thing that I will do in the future is try to find some strains that do well in hotter & more humid climates. These are probably borderline OK for that, but probably not the best. These are probably better in a temperate climate vs. a hotter & more humid climate. Anyway, I haven’t been doing much defoliation, but I chopped off a couple buds from the bottom right corner since they were flopping into the door panel, & they are hanging in the cabinet with the intake filter. I’ve been slowly cutting the add-back to reduce nutes, & the leaves are starting to fade. Trichomes have been clouding up, some of the older ones have started to turn amber. Not sure what is going to be ready first, or if I’ll chop everything at once, I’m just going to watch & see how they progress. I have a lot of foxtails & fluffy buds & I should probably reduce the intensity of the light, but I’m more worried about losing these plants to low light & low nutes than having some foxtails or fluffy buds. I would probably lower the intensity if I had a more even & shallower canopy.

Some data from last night & today. Last night was not too humid, & I got good results by letting the A/C run through the night at its usual daytime setting. It was dry enough last night that my anti-humidity fan was cycling at its setpoint & not running away. The big humidity spike in the AM happened when that fan is timed to shut off at lights-on, yet the light has not yet heated up the room enough to kick on the main exhaust fan. Later on, the big drop for about half an hour is when I opened the door to tend to the plants.

-These charts are all generated from my sensor stationed at/near the top of the canopy.

Lights-off:
75.4f, 65%RH

75.4f, 62%RH

73f, 68%

73f, 65% RH

Lights-on:
84.9f, 62% RH


84.6f, 50%

85.1f, 50%RH

I also checked the leaf surface temps during lights-off, opening the door a few seconds before the light turned on. They were two degrees below the air temp. Leaf surface temps during lights-on varies a lot depending on where & when you check, but I’m usually seeing 78-82f on the tops of tallest buds, anywhere from 71 thru 75f at the top of the canopy, & as low as 72f below the canopy, right as the exhaust fan turns on. Then I’ll see 75f at the tops of the tallest buds, as low as 69f at the top of the canopy, & then below the canopy actually seemed to maintain right around 72f, after the exhaust fan had exhausted & just turned off. That’s pretty much how I’ve been checking the LSTs, either right when the fan kicks on, or right after it kicks off. Then I can take all of it & try to see how the box is running VPD-wise through these ranges of temps & RH.

Still in a heat-wave, today was 95f but still low humidity at around 40%. Tomorrow & the next day are supposed to be the worst days yet, probably going to be near or over 100f for both of them, & more humid. Should be a good stress-test for my setup.

Week 10 begins today.
Here were the canopy temps & RH on the hottest day of the year the other day:


Box was keeping up, cycling between around 84.5 & 85.1f, & the RH was nice & low. Leaf temps were running about the same as the had been, maybe a degree higher overall. Everything was heat-soaked & heating up faster & running a just a little hotter overall.

Humidity has gone up over the past couple of days, probably going to get worse this week. Here is the plot from today, still not bad & Leaf VPD numbers were good during lights-on. Lights-off is seeing some high RH numbers & Leaf VPD would have been around .85kPa where I have the cursor, right before the light turns on. Not great but not as important during the dark. I’m more worried about mold. :

The green is starting to fade:

The buds on the front right really blew out. The rest aren’t so bad, but there are some foxtails growing out of all of them.

I’ve been pruning some of the lower sucker stalks from the plants on the right as they are starting to look a little yellow:

This pic is a few days old, some purple buds on the bottom of the Front Left plant. I may have said earlier that both plants on the left were purping out, but it’s only the front left one.

Most of the trichomes on the buds that I can easily check are mostly cloudy, very few amber yet. Still looking at chopping it all down by the end of this week even though it might be a bit early at least for some of the trichomes. The plants will probably have trouble pulling through an eleventh week as the nutes continue to be tapered off.

Week 11 begins today. I’m going to try & keep it going for no more than one more week. Next week is going to be hot & humid. Not great for growing in my box, but probably safer in there alive than harvesting into a week of a lot of humidity. In seven days, it’s supposed to be dry out again. The trichomes could use more time, but another seven days will be pushing it given that I’m adding back with straight H2O now, sometimes with H2O2 + SM90, or PH UP. I defoliated many faded yellow fan leaves from up top, probably about 30 to 40 leaves. I left the yellowing sugar leaves. Underneath is hanging in there but a number of leaf tips are starting to yellow, & kicking out a few dying/ dead leaves, mostly from the plants on the right, & I’m pulling the dead leaves out as they appear. I’ve also been chopping some of the few remaining stalks that were still below the canopy, opening things up a little.

Before Defoliation:

After defoliation:

Very hot out today, box was reading nearly 86f around the ‘tallest bud level’. Leaves picked up a degree or two across the plant. There was also low RH out today, but too hot for me to pull in any outside air to try & drop the humidity any more. Just didn’t want to feel it at all. So my Leaf VPD was probably not always in a good spot, but it is what it is.

Couple days old:

Mid-week update, since these should be out of here by Thursday or Friday. Tied up a few floppers, & I pulled a few more yellowing fan leaves off. Also removed some more undergrowth.

It’s been very hot & very humid outside for the past couple days, the lights-out humidity looks like it got a little crazy last night, & it’s running higher in the box during the day than it would if it were lower outside. Leaf temps are anywhere from 76f to 82f when the box is warmest, & they’ll drop 5f to 10f after the exhaust fan has cycled, before warming up again. Leaf VPD moves between OK & not so great, but the plant is drinking well & not giving me any major issues.

Taken on Harvest Day:

Then these two moved in.

Resetting, cleaning, etc:
Left bucket:

Right bucket:

I moved the humidity controller to outside of the grow-space. Upper white cord goes to my humidifier power distribution block. Lower white cord goes to my “lights off anti-humidity fan”, & will be plugged into the timer during flowering. For now I left the timer off but plugged into power so its internal battery can remain charged.

Decided to work with the less cranky of the two:

Yep, already root-bound at the bottom again.

I tapped off all of the lava & combed the roots out, & I did prune some that were hanging down a couple inches, & a couple that were knotted up/ damaged. After that, & rinsed with nute solution:

Once the bucket was ready to go again, in she went to some “Week4” solution a few days early. It’s only about 25% stronger than the “Week3” solution she had been getting. PPFD set to 300, just a little less than coming out of the mini-cab in case the move stresses her out.

I let everything stabilize overnight to see where things would end up, & I started making temperature & humidity adjustments today.