New Grower Roc Bud emerging issues

[BoCoGrow]

I'm currently growing 2 Roc Bud Inc. freebies (strains unknown) in OF in 3gal fabric pots. Today is day 32 since sprout.

For the first 30 days, I only gave them RO water with Cal-Mag and Silica Blast each at 5ml/gallon, PH'd between 6.2 and 6.6 (most often 6.5). They have been looking green and healthy, with fast growth. Roughly 4-5 days ago, the leaves at the base of the plants started to lighten in color with some yellowing and spotting. Leaves started drooping significantly 24/7. My assumption was that they were getting hungry and so yesterday, I top dressed with Build a Flower (and some barley straw on top), but the discoloration seems to be starting to make its way up the plant. The tops of the plants look great, but the middle and lower parts of the plant are very droopy and looking tired. Bud development seems to have stopped the last couple days.

I do see that the environment has been fluctuating a bunch recently and more than before. Temp throughout the day can vary by 15 degrees (F) or more. I'm not sure what is causing that as I work the same daily routine; go in about 30 minutes before lights out to turn on and set the oil-filled heater, then check on them after the lights turn back on to lift the pots. Other than that, I try to practice LITFA. Could this be due to the enviro. swings, or is this nutes, PH, or something else? Some pics (the leaves look a lot worse in person):

 

[BoCoGrow]

Something that comes to mind is that I haven't recalibrated my Blue Lab PH pen since I first did so a month ago. I haven't dropped it or otherwise manhandled it, and I've consistently added storage solution to the cap after each use. But I'm wondering if I might need to recalibrate it (i.e. my PH is off)?

 

[BoCoGrow]

Something that comes to mind is that I haven't recalibrated my Blue Lab PH pen since I first did so a month ago. I haven't dropped it or otherwise manhandled it, and I've consistently added storage solution to the cap after each use. But I'm wondering if I might need to recalibrate it (i.e. my PH is off)?

OK, I poured some fresh 4.01 and 7.0 and tested the PH pen. It is still calibrated correctly so we can cross that off the list.

 

[BoCoGrow]

@Mañ'O'Green I would value your opinion if you have one. Might my use of Cal-Mag locked out something else? Biobizz and a longtime grower I know (and other sources) recommended adding Cal-Mag when using RO water, but truth be told I'm not sure whether I need it or not. During the first four weeks the plants were super happy and growing quickly, so I assumed it wasn't doing any harm. But until top dressing the plants yesterday, I haven't given them any other nutes, so I'm thinking it has to be a deficiency/lockout? Perhaps OF has sufficient Cal + Mag that I didn't need the extra?

 

[McDee]

OF is filled with nutrients which is why folks say it hot. A lot of the people in the infirmary are using it, big reason they're in the infirmary. MOG knows his stuff he can help out much better than I, but 1st I would switch from OF. I have used it, you can but gotta be mindful when doing so. I would recommend Happy Frog over OF if you're gonna keep using Fox Farms. To many people have issues with it bud sorry to say. Also you can cut with coco loco if you have it. Good luck bud and stay lifted.

 

[BoCoGrow]

Adding @Tom Bombadil too. Tom, you had previously mentioned that I'm getting started a bit late on the top dressing. Could it be that the plant ran out of sufficient nutes and need some time to take in the food in the top dress? I also have Dr. Earth 4-4-4 and 3-9-4 in the event that it needs something extra. Thoughts?

 

[Mañ'O'Green]

Yes, I believe you have hit the nail on the head. Too much Cal-Mag. With OF you cannot really flush as that will most likely cause more problems than it solves. Stop adding Cal-Mag and feed balanced nutrients at 50% strength and hopefully it will clear up. It is likeley to look worse before it gets better.

Read this as a refresher:

Tutorial - A word on Nutrients

The proper use of “salt” based fertilizer to grow Auto Flowering Cannabis. Salts: Natural and man made any chemical compound formed from the reaction of an acid with a base, with all or part of the hydrogen of the acid replaced by a metal or other cation. Learning how to use salt based...

www.autoflower.org

You should calibrate the Blue Lab Probe every 30 days minimum.

Something that comes to mind is that I haven't recalibrated my Blue Lab PH pen since I first did so a month ago. I haven't dropped it or otherwise manhandled it, and I've consistently added storage solution to the cap after each use. But I'm wondering if I might need to recalibrate it (i.e. my PH is off)?

 

[Tom Bombadil]

Everything MOG said
also you could bubble up a tea with your build a flower top dress like half a cup / to a gallon of water and mix in a little molasses.. might help the plant a little while it recovers
GL

 

[BoCoGrow]

Yes, I believe you have hit the nail on the head. Too much Cal-Mag. With OF you cannot really flush as that will most likely cause more problems than it solves. Stop adding Cal-Mag and feed balanced nutrients at 50% strength and hopefully it will clear up. It is likeley to look worse before it gets better.

Everything MOG said
also you could bubble up a tea with your build a flower top dress like half a cup / to a gallon of water and mix in a little molasses.. might help the plant a little while it recovers
GL

Thank you both, I appreciate you sharing your knowledge. I'm frustrated, but will just take it as a learning experience so I don't repeat it next round.

 

[Mañ'O'Green]

Everything MOG said
also you could bubble up a tea with your build a flower top dress like half a cup / to a gallon of water and mix in a little molasses.. might help the plant a little while it recovers
GL

@Tom Bombadil when a plant is in a lock-out the last thing you want to do is magnify it with a sudden influx of molasses and unbalanced nutrients. Teas can be too intensive at this point. Best to back off and let the pot cool down.