Day 29 - Topped at the third node to start the mainlining process. Stuck the cutting to see if I can root the clone in case it's a really nice genotype. As seen in the photo, it looks like the beginning of a cal/mag deficiency so I lightly watered with cal-mag to rectify that.
A little gutted by a dumb mistake; I removed the wrong fan leaves. After removing the fan leaves from the base of the two new growth tips I realized my mistake, and left the fan leaves on the second node instead. We'll see if the root mass is large enough to keep her growing without causing too much of a stall.
Day 30 - I had detected the mg deficiency starting yesterday so I gave a small amount of cal-mag. I initially thought the damage to the lower fan leaves was calcium, but since it's occurring on the lower leaves it could also be phosphorus. After pruning there are only two lower leaves so if phosphorus needed to be mobilized there is a limited source for it to come from. I think this would manifest the deficiency very quickly in those leaves. I watered with a balanced solution to 120ppm N. She's responding well after the pruning yesterday, and reaching for the lights.
Day 31 - A lot more damage evident on node 2 fan leaves so I just removed them at this point. I increased the temperature to increase the rate of vegetative growth. Humidity dropped a little lower than I wanted so I fixed that on Day 32.
Day 32 - Plant responding well to increased temp. I turned up the humidifier a bit to try and lower the VPD a little. Will turn the humidifier up to increase further. New growth tips fully formed so I topped for the second time. I'll tie down those growth tips when they develop enough.
Day 33 - Still concerned about phosphorus deficiency. It can't be a deficiency, and would only point to a lockout for some reason. I checked the soil pH and it's sitting at 6.2 so that's not it. When I performed the pour through the run off was coming out with a ph of 6.0 so I'm very confident that pH is not the issue. I'm going to just continue to monitor the situation, and if it doesn't improve over the next two days I'll perform a heavy flush, and reset the fertigation. I suppose it could be an abundance of iron or zinc, but not from anything I've added.
Day 34 - Happy with the health of the plant. Should be able to tie down the four growth tips in the next couple of days.
Day 35 - Seeing necrosis in the margins, and leaf tips where I spotted the purpling from the phosphorus deficiency earlier in the week. I don't see any progression of the deficiency so I'll continue to monitor. Growth of the new growth tips steady.
@SugarBoogers, Thanks gromie! Yeah I grow in a space most would consider too small for their seedlings (20"x20"). I figured I better take the extra time in veg to mainline her, and keep her as tidy as possible. One more week and I'll flip her to flower. Clean up lower skirt in about four more days to give her a few days recovery before flipping.