Possible N deficiency?

[afman916]

You're right - I just need to get the tools and check the last couple of unknowns...do you have any recommendations? I don't mind spending the money and would rather do it right once than have a tool that craps out in a grow or two and needs to be replaced.

Planning on watering tomorrow morning and just picked up some blood meal and epsom salts tonight while I was out. What would you do for watering tomorrow considering that even with Prime I won't get my tools until Tuesday most likely. Water with plain water? Add some blood/epsom/CalMag? Push watering out a day until I can measure things?

 

[FletchF.Fletch]

HM Digital ec meter is around $20 or so and it works perfectly. Bluelab makes great meters but they all fail eventually whether they're cheap or pricey, it feels a whole lot easier replacing an inexpensive one once a year than it does when you've shelled out decent cash for a better one.

I would do a plain water irrigation and measure your runoff ph. Testing just ph can show if the whole thing has gone acidic. Also i would save a couple Tablespoons of the runoff to test with your ec meter once it lands. That will save you from having to drench again for your ec reading.

 

[afman916]

Sounds good, thanks man! I'll order meters tonight.

On testing runoff - how can I do that with the liquid drops kit, when the runoff is already tainted color-wise (looks like weak tea)?

 

[FletchF.Fletch]

Sorry forgot you were using the liquid ph test kit. In that case, Hanna and Bluelab are good, Apera Insruments makes a good one in the middle price range and you can order replacement probes too. I recommend getting seperate meters over the combo models. Cheaper to replace the one that goes first than to buy a whole new Combo meter.

Then it's a judgement call whether to wait until the meters arrive before watering. My gut says just give them water tomorrow, then do a runoff watering and measure once your meters get to you.

 

[afman916]

Awesome, thanks for all the help, seriously.

On the meters; can all EC meters test ppm/TDS and vice versa?

 

[FletchF.Fletch]

You're welcome.

Most meters will allow you to switch between ec and tds.

Best of Luck!!

 

[afman916]

Meters are on the way, should arrive tomorrow. Did a plain watering today and some final defoliation. Big girl in question had a few more leaves that had yellowed out, but her new growth still looks great. I’ll post a few more pics later today once I get them uploaded.

Looking forward to being able to test these final few metrics and get this figured out for the remainder of flower. Bud sites are developing great and I’m really hoping I can get things dialed in for a great harvest.

 

[afman916]

So I was just upstairs checking on things and I wanted to ask a few questions that I thought I was clear on, but can’t hurt to ask again.

What temp should I be shooting for? I’ve been shooting for 75 ambient, but I’ve got my thermometer hanging about midway between tallest branches and shortest, so some of the flowers on the indicas are registering 72 or so on IR therm. Root zone as measured by outside of smart pot and top of mulch is around 66-67.

How high above tops should lights be? Right now I’m measuring about 18” from tallest Sativa branches down to 24” for shortest indicas.

How much light intensity? Again, I’ve been dialing in for 70k tallest branches, which leaves rest of plants somewhere between 45-60k depending on height.

I’m trying to bring all the parts together (fan speed, LED height and intensity, 2nd floor thermostat control) perfectly, I just want to make sure I’m shooting for the right things. I’m trying to get fan speed just right so as to not suck out all the humidity while also being mindful of tent temps, which I’m secondarily controlling with 2nd floor thermostat.

As of now, my approach has been keep 2nd floor around 66-68 degrees, fan speed low to medium low, and I’ve got a humidifier pointed at right hand floor inlet. LEDs pegged to about 3/4 blast, 18-24” away.

I thought I had it all dialed in but again, can’t hurt to ask...

 

[afman916]

Meant to say LEDs pegged to 3/4 “power”

 

[FletchF.Fletch]

It really does sound like your environment is completely dialed in, with nothing left unconsidered. Light distance is correct. Biggest thing is you're paying close attention, they'll reward that later.

 

[FletchF.Fletch]

Go 100% on light strength once they respond to the treatment this week.

 

[afman916]

Got it - even if that results in >70k? Or should I raise lights further to compensate?

 

[FletchF.Fletch]

Exactly, raise them if needed.

 

[afman916]

So meters just arrived and I was able to test ppm and EC of the Deer Park for baseline (waiting on pH meter to sit in solution for 15 min before I can use).

So here’s what I’ve got:

EC (ms units): 0.1
EC (us units): 135
PPM (0.5 sensitivity(?)): 64
PPM (0.7 sensitivity(?)): 88

I think the 0.5 and 0.7 are the sensitivity settings for PPM? Not sure, so I included both.

I think I should interpret this as the Deer Park being much lower in TDS than I thought and subsequently, I have a Cal/Mag problem.

Thoughts? Will respond with pH as soon as I test. And will also test what’s been my standard “nutrient solution” on Thur when I water again, as well as capturing and testing runoff across all four plants.

I should have done this sooner, I really enjoy getting in the weeds on things!

 

[FletchF.Fletch]

Congratulations! Life is about to get easier. Testing your values will give you your baseline info so you can be more confident and certain. With soil, you won't need to test all the time like with hydro but it really makes it easier to trace the causes of any problems and correct them much more quickly. You will be happy you bought those meters. Now you may find yourself tempted to try an easy hydro plant just because you have the meters!!

 

[afman916]

Thanks! Definitely easier when you can know all parameters.

ph just tested at 7.4, so a little higher than I thought. Not sure how much my amendments buffer down, so will find out on Thursday.

So I’ve been sitting here reading up on ppm/TDS; is the goal to have most of your minerals be present in the soil, and not the water? So even though my TDS read low with the Deer Park, that shouldn’t matter so long as my soil is amended properly?

And then in testing the runoff, you get a clearer idea of what actually is present in your soil? And to get the CLEAREST idea, you allow a 1:1 ratio of your soil to distilled water to sit and precipitate out over 24 hours and then filter and test that water?

I’m just trying to make sure I fully understand A) what all these values mean B) best ways to measure the values in order to inform proper decisions.

 

[FletchF.Fletch]

Testing the runoff doesn't tell you what's present in the soil, it enables you to understand what's happening to the stuff you're adding to it. Testing the runoff is a way to check that things are not out of balance. Generally, if ph is good all is good, no need to check runoff ec except for general monitoring. If your ph is really low, the ec will probably be really high. Concentrated unused nutrients will affect your ph even if they are Organic.

I haven't tested soil that way, seen it described but find that if solutions going in are measured and runoff is monitored usually everything else falls into place especially when the environment is within acceptable range.

Happy Growing!!

 

[afman916]

Got it, thank you! So if I test my nutrient solution across the board, water, then test runoff across the board and everything seems in line, it’s safe to assume that any symptoms I’m seeing can then be attributed to nutrient deficiencies of some sort?

 

[Mattbho]

Too cold for led if you burning hps your Temps would be ideal . I don't grow sativas, but I shoot for 80-82 canopy temp 68-72 root temp until last 2 weeks with my hybrids . I've read sativas like it a tad warmer .

I like to dim the lights a little the last 10 days 75-80 f temps

 

[afman916]

Thanks Matt, I’ll keep a closer eye on temps and regulate accordingly.

Just got done with my watering and raising the lights so I could take them to full power (will post some pics later).

For the watering, I took baseline readings, nutrient mix readings, and runoff readings from the HxP. I also gave everyone an extra liter of plain water, because a few people mentioned two liters twice a week seemed a little low. I paid close attention to runoff with that last liter to make sure they weren’t saturated and that it wasn’t all running out - it wasn’t. With that last plain liter I added roughly 0.5g calcium nitrate for the HxP girl - but I removed the runoff to test PRIOR to the calcium nitrate liter, as I didn’t want to have that skew results; my plan is to hopefully not need that calcium nitrate watering each time.

Anyway, here are my readings - interested in any thoughts, and will post pics later. There were a few more yellowed/browning dead leaves on the HxP, but I don’t see as many new ones; I’ll keep an eye out for progression up the plant over the next week.

BASE
ph: 7.4
EC: 0.1
TDS (0.5): 64

NUTRIENT MIX
pH: 6.5
EC: 2.3
TDS (0.5): 1153

HxP RUNOFF POST NUTRIENT MIX
pH: 7.1
EC: 2.2
TDS (0.5): 1118

Overall I really think these girls are looking good and hoping for my best harvest yet! Will also take new lux readings and height measurements due to moving the lights up. I have two 240w Kingbrites pegged to 100% power though, so I’d imagine I’m still ok even if they look a bit too high...

Thanks all for the help and guidance!!