Suspected Zinc Deficiency - Dwarf Low Flyer & Auto Gelato

[GreenBasterd]

Hello crew, thanks for looking at this.

-Problem: Leaves on new growth are yellow and thin. Leaves on old growth is starting to turn yellow from the center out. Prior to bloom/flowering, everything was beautifully green using Botanicare Pure Blend Grow + Bloom City Cal-Mag. Problems began shortly after flowering got under way.

-Medium/grow method: 70/30 mother earth coco/pearlite mix in autopots.

-Feed and supplements used: Botanicare Pure Blend Pro Bloom - 75ml per 5 gallons (half recommended strength). Bloom City Pro Grade Ultra Pure Cal-Mag - 20m per 5 gallons (I mix everything in 5 gallon jugs and then add to the autopot reservoir.

-Water source: Using R/O water 0ppm to start. PH balancing using gen hydro drops. In growth stage I kept things around 6 (yellow looking test water). To try to fix this issue I dropped to what seems like 5-5.5 - light orange test water. Hard to be 100% accurate with the drops but I had it wired during veg.

-Strain and age - beginning 11th week now. 2 strains - Dwarf Low Flyer is getting the yellowing worse, auto gelato is resisting better but still feeling it.

-Climate: Temp day - 80F. Temp Night 74-76F. RH dry - 40-45%

-Light used: LED - 18/6 schedule, Mars Hydro FC-E6500, 680 Watt. Closest tops are at 17" and they are the most yellow. May be it's too much light with no CO2???

-Additional info: Symptoms started showing 2-3 weeks ago as flowering began and I switched nutes. The only other option I have for nutrients currently is the GH 3 part flora system. So I could switch to that if it would be better.

--Pictures - note, the close up photo is slightly MORE yellow than reality, but blades on Dwarf low flyer are very thin and unhappy.

 

[Mañ'O'Green]

@GreenBasterd Welcome to AFNI think you have a salt build up causing a lock-out. Do a good 100% flush from the top by slowly pouring PH 5.8 water through the pot and get rid of the waste water. Then feed from the top your normal nutrient mix. Then go back to the autopot feeding. It is a good Idea to flush coco once a week in flower.

Now lets talk tools. You need some good tools to grow with hydroponics. EC meter, get a good one because 1ml/g or 10ml/g is really not good information when it comes to plant nutrition. Auto flowering plants seem to do best ~550 PPM of nutrients total. PH pen, the life of your crop literally depends on proper PH. Liquid testing is better than no testing but...............

 

[GreenBasterd]

@GreenBasterd Welcome to AFNI think you have a salt build up causing a lock-out. Do a good 100% flush from the top by slowly pouring PH 5.8 water through the pot and get rid of the waste water. Then feed from the top your normal nutrient mix. Then go back to the autopot feeding. It is a good Idea to flush coco once a week in flower.

Now lets talk tools. You need some good tools to grow with hydroponics. EC meter, get a good one because 1ml/g or 10ml/g is really not good information when it comes to plant nutrition. Auto flowering plants seem to do best ~550 PPM of nutrients total. PH pen, the life of your crop literally depends on proper PH. Liquid testing is better than no testing but...............

Thank you Mañ'O'Green. Appreciate it. Now to figure out how to move each autopot with air stone outside for a flush. I guess I'm going to have to disconnect all the lines and just get it done. Sorry, I did measure the PPM once and it is right about that range. It's about 1/2 of what MFR recommends. Maybe using better nutrients won't cause this next time. Also possible the mother earth coco mix wasn't rinsed enough by the manufacturer. I'd like to get one of those blue labs PH monitors actually. PH pen may be smarter though since it's mobile.

 

[Mañ'O'Green]

Thank you Mañ'O'Green. Appreciate it. Now to figure out how to move each autopot with air stone outside for a flush. I guess I'm going to have to disconnect all the lines and just get it done. Sorry, I did measure the PPM once and it is right about that range. It's about 1/2 of what MFR recommends. Maybe using better nutrients won't cause this next time. Also possible the mother earth coco mix wasn't rinsed enough by the manufacturer. I'd like to get one of those blue labs PH monitors actually. PH pen may be smarter though since it's mobile.

Whenever you bottom water - autopots, flood table etc. - where the water level does not exceed the inert media top surface level there will be a salt line zone. This is a physical characteristic of the nutrients weight and the waters ability to carry up it as it is evaporating. Salts in this zone accumulate and become toxic to the plant by locking some nutrients out.This usually only happens if the pot is not watering enough. So it is not the brand of nutrients that causes this. It is simply part of growing in coco and bottom feeding.

If your salt build up is sever? even flushing can cause problems.

Get a little pond pump at home depot for cheap and pump that water out to a bucket. Moving your plants is not a good idea.

 

[GreenBasterd]

Whenever you bottom water - autopots, flood table etc. - where the water level does not exceed the inert media top surface level there will be a salt line zone. This is a physical characteristic of the nutrients weight and the waters ability to carry up it as it is evaporating. Salts in this zone accumulate and become toxic to the plant by locking some nutrients out.This usually only happens if the pot is not watering enough. So it is not the brand of nutrients that causes this. It is simply part of growing in coco and bottom feeding.

If your salt build up is sever? even flushing can cause problems.

Get a little pond pump at home depot for cheap and pump that water out to a bucket. Moving your plants is not a good idea.

So then, this is unavoidable with Autopots/bottom feeding? In other words for every grow they're going to require a mid-grow flush? Or pre-flower flush at least? If so, may just give a deep water culture system a shot. This was my 1st Autopot attempt. Went real easy through VEG stage.

 

[tronN00dles]

Whenever you bottom water - autopots, flood table etc. - where the water level does not exceed the inert media top surface level there will be a salt line zone. This is a physical characteristic of the nutrients weight and the waters ability to carry up it as it is evaporating. Salts in this zone accumulate and become toxic to the plant by locking some nutrients out.This usually only happens if the pot is not watering enough. So it is not the brand of nutrients that causes this. It is simply part of growing in coco and bottom feeding.

If your salt build up is sever? even flushing can cause problems.

Get a little pond pump at home depot for cheap and pump that water out to a bucket. Moving your plants is not a good idea.

Can you elaborate on why moving plants is not a good idea? I'm guilty of doing this....

 

[GreenBasterd]

Can you elaborate on why moving plants is not a good idea? I'm guilty of doing this....

I had to move them to rinse too. Basically rinsed each out in the shower with slightly off balanced but good temp water, then flushed again with a few gallons of carefully balanced water. Overall was a bitch! Wish I'd tried a DWC system before the autopots. Though they were easy as hell up until this point.

Checked my PPM again though and I'm way off the recommended. Up at 1100 or so and will cut that down today by diluting the mix a bit.

 

[tronN00dles]

I had to move them to rinse too. Basically rinsed each out in the shower with slightly off balanced but good temp water, then flushed again with a few gallons of carefully balanced water. Overall was a bitch! Wish I'd tried a DWC system before the autopots. Though they were easy as hell up until this point.

Checked my PPM again though and I'm way off the recommended. Up at 1100 or so and will cut that down today by diluting the mix a bit.

Is that 1100ppm or 1100uS/cm? The latter would be perfect.

 

[GreenBasterd]

Is that 1100ppm or 1100uS/cm? The latter would be perfect.

No, it was PPM.

 

[tronN00dles]

No, it was PPM.

Yeah that's high lol. I'm currently running photoperiods in Mother Earth Coco 50/50 perlite mix, and my infeeds don't exceed 625ppm, and my run-off doesn't exceed 700ppm. For autos, I'd be down in the 500-600 range for sure.