Wow, it's been three weeks since an update!
There has been a lot of work to get nutes straightened out and very little of it has been my doing.
@FelipeBlu has been very kind and very patient to share his expertise with me and has dealt with the nute issue that was plaguing the grow.
After FB gave me his valuable advice about nutes, I started to dig around a bit and found a lot of good info about mixing your own. I don't see the value in that for me but the learning aspect of that part of growing cannabis is intriguing and I have decided to move away from bottled nutes and go to Jacks. More on that below.
Another big issue I've had to deal with is Jeff, whom I've labeled an "invasive plant". Jeff grew so much that I had to cull Winnie, the plant that was in the center. Jeff simply grew over her and, when I removed her from the tent, she was only getting 143 µmols. Some of Jeff's stalks are almost 60" above the top of the res with many of the stalks growing up past the light. On the other side of the res, Mary is roughly 12" tall. Two vastly different growth patterns even though the plants have been LST'd and super cropped.
It was in a losing battle to try to light both plants with one light, so I had to either cull Mary and let Jeff spread out all over the tent, or I could have added a light for Mary and used the X3 to light Jeff. I didn't want to toss out a few months of growth for the sake of $100± for a light so I ended up with a ViparSpectra XS-1500.
The best solution was a single bar light with a dimmer to fill the 2' x 2' space. ChilLED is on backorder, as usual. The Mars SP 150 lacks a dimmer and looks more like a veg light than a smaller version of the SP 3000 so I ended up with a ViparSpectra XS-1500. Like the Mars SP 150, the XS-1500 has a lot of blue in it but it's not as red-starved as the Mars. I ordered it last Sunday, Amazon delivered it the next day, and I had it up and running within a few minutes. At 14" x 11", it's a perfect fit for the space and it weighs only a couple of pounds.
With the new light running to keep Mary happy, I raised the X3 and was able to drop the wattage. When I was trying to light Mary and Jeff with one light, I was running the X3 at 300 watts and some parts of Jeff were > 1200 µmols while Mary was at 350± µmols. After installing the XS-1500, I dropped the wattage on the X3 to 245 and still get great light on Jeff.
Thanks to the additional light, I've been able to get about 900 µmols on both Mary and Jeff, though some parts of Jeff are 1000 or a bit more. I am not concerned about PPFD values that high. I continue with my efforts to get my head around how cannabis reacts to light and my take away is that, lacking doing something like dropping a monster light just a few inches above a canopy, cannabis will absorb pretty much anything you hit it with. The approach that I'm taking is to get 900 µmols on all parts of the plant and there's no issue if some areas are in the 1200 or 1300 range.
Now that we're here at day 80, the tent is getting a rich, sweet smell, Mary has both clear and amber trichs (very few amber), and the trichs on Jeff are just starting to show . As you can imagine, I'm really glad to see that things are finally heading into the home stretch.
And what pops up its head now that nutes are under control and light levels are great? You guessed it - temperature! Winter is nigh here in SoCal and daytime highs are dropping into the 60's, with some overnight lows in the high 40's. When I swapped out the Mars SP 3000 for the X3, I swapped out a 1 bar light for a 3 bar light so I don't have space in the tent for my little oil heater. As a stop gap, I moved the power supply for the X3 into the tent (it's hanging above the XS-1500) and the tent is now 75, up from 66 when the lights went on this AM. I might have to resort to taking the car for a drive to get heat back in the tent. And, as I'm coming to accept, the only long term solution for some of these issues is to either not try to grow in either the "cold" of winter (
@Rexer laughs) nor in the heat of summer or I need to switch to a 4' x 4' tent and which will give me room for an AC unit, a dehumidifier, and a heater.
The biggest change is that this will be the last res with Botanicare Kind nutes. I tried to reorder "Bloom" and I've learned that, thanks to my betters here in the People's Republic of California, it can no longer be sold in California. That's a pisser because, until a few weeks ago, I had no reason to not try to keep using Kind nutes. After getting help from @FelipBlu, I roamed around the internet for a bit (it's OK, I'm over 21) and found that nute recommendations vary tremendously.
After a few months of trying to find the best way to do almost anything having to do with cannabis, I'm seeing that there are experts all over the web who have an answer and, in many cases, those answers are quite different. Are these people bullshitting readers/viewers? Perhaps but, to my way of thinking, it's not that they're bullshitting but that, one, cannabis will grow well under a wide variety of conditions and, second, the vast majority of what we read about cannabis is full of confirmation bias.
Seeing that Botanicare's Kind is end of life here in the PRC, I decided to switch to Jack's and am going to be using their two-bag "321" program. The new nutes will be here this week so now I need to make the switch from adding liquid nutes using beakers and syringes and get used to mixing nutes using a gram scale and a paddle.
Seeing that I'll be switching nutes in a few days, I didn't swap the res this weekend. For the last res change, I upped the TDS to EC 1.6 and Mary got some nute burn. Dropping the res to 1.5 cleared that up. Repeating the pattern that I've seen for the past few weeks, after swapping the res, pH drops about 0.1 unit every 90 minutes for 5 days and then it evens out. pH was 6.1 at lights out last night and didn't drop at all overnight.
Water uptake is significant. I added 4 gallons of water + nutes today and left the res at an EC of 1.5 and a pH of 5.8.
Light levels are high. After reading yet another excellent research paper ("High light intensities can be used to grow healthy and robust cannabis plants during 2 the vegetative stage of indoor production"), my opinion about lighting is to increase light levels so plants they receive a PPDF of at least 900 µmols as early as possible inter lifecycle. I don't want to delve into CO2, which would allow me to push that level even higher, and, on the low end, the cost difference between 600 µmols and 900 µmols is offset by the increased yield, even at 23¢ per kilowatt.
Light levels are "high" - "how high are they?", you ask. Jeff's readings at canopy level on the X3 - 930, 825, 1055, 1100, 860, 995, 700, 1121, 800 which is an average of 931 and a STDEV of about 150. Mary's PPFD readings - 859, 831, 700, 1130, 1300, 1000, 575, 610, 681, 1160 which is an average of 885 and a STDEV of 252 - not quite as good as Jeff's getting but still excellent and much, much better than the goat rope that I had before I added the XS 1500.
The plants have a heavy, sweet scent to them and, perhaps thanks to the blue heavy spectrum of the SP 3000, there look to be a lot of nugs stacking up on each other. Mary is a five days older than Jeff and her buds are significantly more mature. I'm guessing Mary will be ready in early January while Jeff won't be taken down mid-January at the very earliest.
Two plants, two lights.
One of Jeff's buds
A topped and super cropped auto flower. Tallest stems > 5' above the res.
One of Mary's nugs.
And another
