underfeeding?

[glacier]

How long has this problem been going on? a week
What system are you running? 4 recirculating waterfarms with rez/controller
What STRAIN are you growing? AK47
What was the establishing technique? seed
What is the age of your plants? 10.5 weeks
How tall are the plants? 4'
What PHASE are the plants in? 4 weeks in flower
What substrate/medium are you using? Hydroton
What is the Water temperature? unknown, but fairly cool
What color are your roots? White? Brown? Are your roots slimy? white roots, no slime
What Nutrient's are you using? GH 3 Part
How much of each nutrient are you using with how much water? lucas 8/16 - 5/10
What is the TDS/EC/PPM you are using? 1.4 EC
What is the pH of the "Tank"? solid 5.8
Are you sure your calibration is correct on your equiptment? yup
How often do you clean your system: every 2nd week
What size bulb are you using? 600w HPS
What is the distance to the canopy? 18"
What is your RH Factor(Relative Humidity)? 50%
What is the canopy temperature? 80 degrees
Tell us about your ventilation, intake exhaust and when its running and not running ? 265 cfm exhause on 24/7, passive intake
Is the fan blowing directly at plants? yes
What water are you using? RO water
Have any pest chemicals been used? nope
Are plant's infected with pest's nope

OK so my plants have been doing great so far.... but this week i've been having some issues. i'm 30 days in flower, and the buds are really starting to bulk up. they've been getting lucas formula 5/10 pretty much the whole time... there was a couple feedings when i started flowering where i gave em 8/16... but the tips started to burn a bit so i went back to 5/10. i was waiting to see the ppm lower before i bumped up the nutes again, but it's been fairly consistant so i didnt bother. i've got a couple of smaller clones in the system aswell, and they're totally happy, so that makes me think it's underfeeding.

this problem seems to only be happening on the mid/upper part of the plants, and it's spreading very rapidly... is this the plants telling me they're ready for more nutes?

last night i drained the system and put in some fresh nutes(5/10) and tonight i'll be filling up the rez with 10 more gallons of solution(once i figure out how much to give em)






thoughts?

 

[Centrum]

You giving them any Cal / Mag ?

 

[glacier]

You giving them any Cal / Mag ?

i actually gave em a small shot of cal/mag last night after i drained the system, only 1 tblspn for 10 gallons of water. but no, i dont give them cal mag on a regular basis.

 

[10k]

I would say that a solid 5.8 is too low....I personally would raise the PH to about 6.2-6.5 for a while. It seems that certain nutrients are not absorbed at a low PH...With the Lucas formula and RO water the nutrients should be in the right concentrations so I would have to go with PH being the problem??

Good luck fixing the problem though...I'm not an expert or anything, but I've been using the lucas formula, and I try to give my plants a 5.5-6.0 PH feed and then the next day more like 6.0-6.5.

Sorry to disagree, but...

In hydro with gh flora lucas mix a swinging range between 5.1 and 5.9 is much more desirable than holding a solid 5.8. Start it at 5.1 and let it slide upwards. Contrary to popular myths a pH of 5.2 is optimal in chem hydro. Never let gh flora nutes go to 6.5 in hydro

Ranges above this 5 to 6 zone start having element precipitation and lockout problems within the solution. P & K becomes mostly unavailable above 6.4

hth,
10k

 

[supersoulbro1]

Sorry to disagree, but...

In hydro with gh flora lucas mix a swinging range between 5.1 and 5.9 is much more desirable than holding a solid 5.8. Start it at 5.1 and let it slide upwards. Contrary to popular myths a pH of 5.2 is optimal in chem hydro. Never let gh flora nutes go to 6.5 in hydro

Ranges above this 5 to 6 zone start having element precipitation and lockout problems within the solution. P & K becomes mostly unavailable above 6.4

hth,
10k

something alot of people dont know or understand let it drift a bit so all of your nutes and be used and always keep a watch on what your ladies want and they will reward ya with gooey nugs

 

[FoothillsFarmer]

something alot of people dont know or understand let it drift a bit so all of your nutes and be used and always keep a watch on what your ladies want and they will reward ya with gooey nugs

tell me more about how this works supersoulbro, you've peaked my interest.

 

[Hydro-Soil]

Sorry to disagree, but...

In hydro with gh flora lucas mix a swinging range between 5.1 and 5.9 is much more desirable than holding a solid 5.8. Start it at 5.1 and let it slide upwards. Contrary to popular myths a pH of 5.2 is optimal in chem hydro. Never let gh flora nutes go to 6.5 in hydro

Ranges above this 5 to 6 zone start having element precipitation and lockout problems within the solution. P & K becomes mostly unavailable above 6.4

hth,
10k

You already have GH Micro and Bloom.... You can throw your Cal/Mag away for a few years. You'll spend a lot less time scratching your head and a lot more time looking at healthy plants.

Listen to 10K as they know what they're talking about. Go look at my journal for an RO and FNB only grow (3-part is the same) without deficiencies or Cal/Mag.

Your issue is definitely pH locking out the Mag that your plants need. They're pushing hard to set those budsites and using a lot of mag. Dump your res, flush everything out with RO for a bit and then re-mix a new res at 0-7-14.

You'll be right as rain tomorrow and all cleared up in 2 days. (At least that's about what happens for me. )

If you get a bit of tip burn on new leaves again then go ahead and drop it back down another notch. (You can also leave a gallon out of your res and add a fresh gallon without nutes in it to dilute it out a bit, if need be.) I think with the T5's you'll find that's not a problem at 7-14.