Post UC Questions and Concerns Here

[UCHQ]

Roots are pretty decently white, some minor brown near the top but very little. I hear you about high EC but that plant is running in 0.2 EC. We are talking 200 ml of H&G plus 100 ml of cal mag for 200 gallons. By serious you mean previous to them exploding or turning to crap?

Your ratio of CalMag to A/B is what is causing you issues. The plants are being supplied with C/M for in excess relative to the other minerals necessary for healthy growth. In your case 33% of your total mineral load is C/M.....it should constitute no more than 15-20%.

Remember, your A/B has ample amounts of Ca, Mg, Fe and N...all of which are also supplied in the C/M your dosing in excess.

I've spoke with the H&G folks and they recommend no more than 1 mil per gallon of C/M if a grower feels it necessary to use. With small plants this can equate to 0.5 mils to supply added C/M.

 

[phup]

Your ratio of CalMag to A/B is what is causing you issues. The plants are being supplied with C/M for in excess relative to the other minerals necessary for healthy growth. In your case 33% of your total mineral load is C/M.....it should constitute no more than 15-20%.

Remember, your A/B has ample amounts of Ca, Mg, Fe and N...all of which are also supplied in the C/M your dosing in excess.

I've spoke with the H&G folks and they recommend no more than 1 mil per gallon of C/M if a grower feels it necessary to use. With small plants this can equate to 0.5 mils to supply added C/M.

That would make sense if I didn't already have the leaf curl issue previous to the addition of any cal/mag. I only recently added it on the hope that it might fix things. Previous nute profile was HG only at EC.3

 

[phup]

oops, there was small amount of epsom there as well

 

[phup]

But you did get me thinking UCHQ. Potentially a mag toxicity that is locking out other nutrients? I appear to have phosphorus deficiency (stems are bright purple) and I am wondering if I've added to much epsom, created a toxicity then compounded it with cal/mag?

 

[UCHQ]

Excess salts (relative to needs) can be very detrimental in water culture due to the prolonged exposure of roots to the solution. When plants are recovering from stress, as yours were, they become especially sensitive to mineral salts.

It's the fact that water uptake is impaired that causes such an issue...purpling stems is also expressed by dehydrated plants as well.

To get your plants to recover now I'd recommend to add A/B to RO until up to 100 ppm and let it ride till they begin to uptake solution. Also consider foliar to help rehydrate the plants.

 

[phup]

Thanks for the prompt replies, I'll update you in 3 days.

 

[phup]

Quick update, Raised the lights to 5 ft above from 3 ft, ladies look significantly better.

 

[MMJQA]

what should i set temp should i set my chiller?

 

[woodsmaneh]

what should i set temp should i set my chiller?

I am at 62 and have been for the last 4 grows, there is a point that is to cold not sure what that is. The reason for the cool temp is for the DO (dissolved oxygen) cold water holds more DO than warm. It is also a good way to prevent root issues, vs warmer temps. Here is a chart that shows you the difference in temp/DO.

 

[ttystikk]

Jalisco Kid and others said that at some pints they ran their water temps as low as 57. I think that was late stage flower, to induce colors and help finish things up, if I recall correctly... That's too cold for good plant growth.

I also run my water at 62-65, trying to keep on target at 64. I'm told- again, anecdotally from what others have said here- that temps below 65 inhibit root rot and pythium.

These temps don't seem to kill off beneficial microbes, so I'm thinking that's a good temp for a 'live' approach, too.

 

[deacon1503]

Jalisco Kid and others said that at some pints they ran their water temps as low as 57. I think that was late stage flower, to induce colors and help finish things up, if I recall correctly... That's too cold for good plant growth.

I also run my water at 62-65, trying to keep on target at 64. I'm told- again, anecdotally from what others have said here- that temps below 65 inhibit root rot and pythium.

These temps don't seem to kill off beneficial microbes, so I'm thinking that's a good temp for a 'live' approach, too.

Cold nute temps late in flower will enhance any colors in the strain; mainly purple from what I've seen.

 

[smokey_waters]

5.5" vs 8" net pots... Need help- was told in flower to have water at bottom of net pot, bit I've also read to have 4 gal's per module (8 gal capacity). The bottom of a 5.5" net pot is much more than 4 gal's per module. So what's up? Are the 5.5" net pots SHORTER than the 8" net pots???
Tl;dr: where is the water level in flower and does it ever change??
Thx,

 

[All4freedumb]

5.5" vs 8" net pots... Need help- was told in flower to have water at bottom of net pot, bit I've also read to have 4 gal's per module (8 gal capacity). The bottom of a 5.5" net pot is much more than 4 gal's per module. So what's up? Are the 5.5" net pots SHORTER than the 8" net pots???
Tl;dr: where is the water level in flower and does it ever change??
Thx,

Did you veg in the UC? I have done both, veg in the UC and off and put into the UC for my last week or so of veg. I like to get my roots popping out nice and full from the UC before flipping into flower. Once those roots are nice and full I drop my water level an inch or so below the net pots. This usually happens at about the same time as the flip. Tex flips to flower strait from his tables at the time of the switch into the UC and I'm not sure were he keeps his water at that time, I would assume the bottom of the pot since the roots have not yet hit the UC. I start my UC run 1-1 1/2in up from the bottom until I see my roots start popping, then I drop the water to the bottom of my pots until I have a nice set of full roots surrounding my net pots and are nicely sumurged into the water, once those roots are nice and full I drop again 1pm below the net pots. I have ran strains that like that depth and I'm sure would be fine for a happy medium for all. Although I have noticed in side by side runs that one of my OG's like to be dropped as low as 2 in below the net pot, I added an extension to my float to achieve this..
Yes the 8in is deeper, I'm not sure if that's when the 8's are running with 4gal each. I hope this helps..

 

[hogan400]

Did my water swap and raised my ppm120 for a total of 640. I flipped to 12/12 and my ph dropped from 6-5.3 in two days. It seems the plants are eating since my ppm is dropping as well...all my roots look perfect. I still have the one plant battling a little stem damage but coming along ok.

Is this normal when you switch to bloom nutes at first? DUTCHMASTER A/B
Do you think I should back off my food a little? raise ph or let it swing?
Am I in for some drastic dealings? I called cch2o but seems they are closed today?

 

[ttystikk]

Did my water swap and raised my ppm120 for a total of 640. I flipped to 12/12 and my ph dropped from 6-5.3 in two days. It seems the plants are eating since my ppm is dropping as well...all my roots look perfect. I still have the one plant battling a little stem damage but coming along ok.

Is this normal when you switch to bloom nutes at first? DUTCHMASTER A/B
Do you think I should back off my food a little? raise ph or let it swing?
Am I in for some drastic dealings? I called cch2o but seems they are closed today?

If your pH is dropping, you likely have the nutrients a little strong. You want the pH to rise over the course of a few days. Switch to bloom nutes a week or so after flip. Just my .02...

 

[hogan400]

ttystikk,
I appreciate the knowledge and was curious if too strong? Next time I will give that a try! I know ph is sup to rise, but if ph is falling and ppm is also falling "very"slowly what other signs should I keep an eye open for? Any thing else I can look for? the roots dont appear burnt or have dead tissue. I will say some of the tips are curled kinda like a hookworm but appear healthy...

I had help lifting each container and inspecting roots. They look amazing and I looked from directly underneath to get a different point of view, and still great?! the plants are growing looking great and stretching already. ph just dropped fast from 6 even though I know 5.3-5.4 is ok....

root temp 64.8
room temp 72 under lights 81
ppm 447 / ec.87
co2 1000 ppm
d master nutes day 2 in flower
r.h 50.5

 

[deacon1503]

If your pH is dropping, you likely have the nutrients a little strong. You want the pH to rise over the course of a few days. Switch to bloom nutes a week or so after flip. Just my .02...

Im under the impression that a ph rise without a ppm/ec drop was a bad thing?

 

[hogan400]

deac,
Im sure you're right and Im still kinda new to uc/rdwc.

ph rises up, ppms go down, because of nute consumption... normal yeah...

ph drops and nutes are are not consumed would be overfeed... see some burns yeah..

ph drops and ppm drops would be cause for the start of rot or bacteria...yeah?

My plants are eating ppms (nutes) yet ph falling some, not on the rise!
Thats what Im seeing, however ttystikk has me thinking my nutes were a little high not to the point of burning, but maybe they are slowing? I could be paranoid for nothing. The ladies are eating a little but not even close to what they were in veg.

 

[woodsmaneh]

5.5" vs 8" net pots... Need help- was told in flower to have water at bottom of net pot, bit I've also read to have 4 gal's per module (8 gal capacity). The bottom of a 5.5" net pot is much more than 4 gal's per module. So what's up? Are the 5.5" net pots SHORTER than the 8" net pots???
Tl;dr: where is the water level in flower and does it ever change??
Thx,

I use the 13 gal mods but you can adapted this to any size by using common sence.
you always measure from the bottom of the net pot no matter what the gallons are or the size of the pot. This is what I do I have an extra net pot and stick it in and fill till it is 1" above the net pot. I put 1 layer of hydroton on the bottom than the veged plant in and fill to the top. I run like this for the first week to 10 days, or till I see roots. Once I see roots I drop it 1" below the pots and a week later, so were up to week 3 and a bit I drop it another 1" so it is now 2" below the net pot. The auto fill keeps it there. For the last 2 weeks I drop 1" a week so my the time I'm done it 4" from the bottom of the net pot.

 

[woodsmaneh]

deac,
Im sure you're right and Im still kinda new to uc/rdwc.

ph rises up, ppms go down, because of nute consumption... normal yeah...

ph drops and nutes are are not consumed would be overfeed... see some burns yeah..

ph drops and ppm drops would be cause for the start of rot or bacteria...yeah?

My plants are eating ppms (nutes) yet ph falling some, not on the rise!
Thats what Im seeing, however ttystikk has me thinking my nutes were a little high not to the point of burning, but maybe they are slowing? I could be paranoid for nothing. The ladies are eating a little but not even close to what they were in veg.

I got this from this site a long time ago forget who it was that spoke this but I printed it out and have it in the room.

If your nutes are at 500ppm and two days later there at 350ppm you need to up your ppm! It works like this change res set ppm at say 600ppm ph 5.9 run for 24hrs, now if you ppm rise and ph drops nutes are too strong. If ppm drop and ph rises, nutes are too weak. But if your ppm and ph are basically stable then you have found the right mix for your plants.
Then when topping off your res use pre mixed nutes to keep it at that level, if it starts to rise or fall adjust top off nutes as needed to bring it back to proper level. This is how I set my system up and has worked great for me for years! Don't worry about the numbers just let the plant tell you what it needs and you will be fine.
:animbong::sun