Need help to use PH meter

[1984]

Hi. My first grow. I have some plants with a problem apparently.
One is a Sweet Afghan Delicious the other a Himalaya Gold. I have other without their symptoms.

Conditions:
Indoor, from seed, soil, fluo start - 400hps, 18/6, aprox daytime temp between 25 and 32 ºc (now on cooler side coming down to 24), humidity unknown, ventilator, distilled water.

Indoor Conditions and development:
1. Started from seed (paper towel method germination) then potted into cannapro soil mix & put under weak fluo. (Notice 2 have hard time shaking seed case above ground and consequent distorted first leaf set). Very small starter pots. Moistured with distilled Ph 5 water.
2. Repotted into half liter plastic pots ( a mistake) when 4 or 5 inches w/ strong stems and vegged for aprox 2 weeks under 150 CFL. Same soil and always distilled water only. Grew very quickly but w/ first signs of yellowing tips on uppermost leaf sets. Biologist at groshop shown pics and said great plants, very well developed for age - nothing to worry about. Read article saying symptoms not to be confused with N def or burn (impossible - no nutes used) but due to cramped roots. Repotted again to 7 liter pots, same soil, same distiiled water aprox every 4 or 5 days depending on weight / look.
3. Put under 400 hps after some aprox 19 days, other 24 days. 18/6 schedule. Grew fast, increased distance from bulb, too hot. Have been using ventilator and increase its frequency. I keep at almost i meter now. In all stages since appearing, the yellow tips keep coming from new growth, there's no change. They keep growing fairly well, strong trunks develop, not too high. I kill all insects I see (not many). Some may be beneficial but I'm ignorant and play safe. Who knows what's lurking under the top soil though?
4. Introduce organic grow nutes at half and then almost full strength. Days between watering increased a bit - this is a guessing game, I think they are under watered, but prefer dry to soaking drowning. I play safe.
5. Get better colour - continue to grow up and out. Use 'oxygenated water', recommended by 2 local groshops, to foliar spray leaves' tops and bottoms to clear dust and encourage light synthesis, transpiration.
6. Watered distilled only. Slow down noticed in growth upwards and top leaf sets, but growth of leaf sets between nodes on body under canopy increases
7. Growth upwards shows general slowing down, more noticeably now, as well as under the canopy as light is not penetrating well below large fan leaves. Have to space them out more. Not much improvement.
8. All are now between 38 and 45 days old and I'm wondering about when to take cuttings. I've read that you should do that when nodes begin to alternate at different heights/angles. That's not happening. I reckon they are a few days short of putting into flowering regime - I don't want too high and they now stand at around 50 centimeters (20 inches). I'm following advice from groshop as they know the strains. The Himalaya Gold is said to need a lower Ph than most other plants but all plants have mostly the same treatment up to now.

Here are the pics: No they're not...how can I include images here?
Ok I've managed to get them in my gallery, how do I link to them? Does this work....no...please, anybody?







The problem is this. I need to water them now, they need it, but wanted to test the Ph for the first time to have a better idea, or at least SOME idea, of what they might need but instead of just watering and measuring the run off, I'm also tempted to flush them (but not with distilled - this is expensive and almost a luxury). On reading the calibration instructions I was bewildered, it makes absolutely no sense at all. I have a pen type meter, obviously not an expensive one, and the person that wrote the instructions must have been stoned. Or may be I am. This is what it says, can someone please explain in simple terms how to use this thing?

"1. Immerse electrode in PH 6.86 (under the temperature of 25ºc) standard buffer solution of phosphate and gently shake.
2. Regulate trimmer with screwdriver until the buffer solution value corresponding to the measurement temperature is obtained.
3. Immerse electrode in PH 4.01 or Ph9.18 the standard buffer solution of borax.
4. After about one minute, until the buffer solution value corresponding to the measurement temperature is obtained."

Questions:
What temperature do 1 and 2 refer to? Room temperature? Solution temperature? How am I supposed to change the temp if it's not 25ºc anyway? I don't get this. What am I supposed to see in the meter window, a temp reading? I thought it was supposed to show ph reading...duh?
Is 3 and 4 an alternative calibration to 1 and 2? If not what is it on about?

I have milwaukee solution ph 7.01 at 25ºc. After a reading, if I manage one, can I go on to measure another pot's run off without re-calibrating?

Thanks 4 your time and sorry for going on a bit. Thought I'd post a few details in case I get any more probs later.

 

[rrog]

I just went through all of this myself with a pen meter. Went and invested in a more accurate probe after this. But:

pH varies slightly with temp. However not a lot, and not so much that a pen meter will detect. But they are referring to nute temp. So just make sure the calibration fluids are at least room temp.

All you need to calibrate is the 7.01 and 4.01. Pen meters can take 15 seconds to equilibrate, so just let it sit there in the calibration fluid to stabilize. Then adjust with the screwdriver.

This calibration will probably last only a week.

Keep the calibration fluids sealed. I like to pour out a small amount into sterilized plastic soda pop tops. Avoid metal.

For cripes sake keep the probe wet at all times when stored. You can use a purchased storage fluid.

When calibrating, I like to keep a small glass of tap water nearby to rinse the probe.

 

[1984]

Thanks rrog. But I don't have any 4.01 solution. When I bought the thing I was given the milwaukee stuff and that implied it was all i needed. I did ask questions about how to do it but what the guy said doesn't coincide with these 'instructions', I mean he said nothing about needing any further solutions....??? I can't do the 4.01 calibration then? Is it that necessary? If i wasn't given the stuff surely some people think not?

So after doing one measurement I wash out the probe with distilled water and can proceed with next?

 

[stinkyattic]

The Milwaukee I have doesn't require a 2-point cal, just the 7.0.
Room temperature refers to 25'C which is part of 'Standard Conditions'; for chemistry (the other being 100kPa of pressure).
You do not need to recalibrate between measurements, don't worry. You only need to recalibrate under these conditions:
-Meter has been exposed to unusually high or low temperature conditions, dropped, or otherwise abused
-Batteries have been changed
-Meter has not been used in a while
-You have had to 'shock' the electrode (dip alternately in conc acid and conc base, rinsing in between, finishing with conc acid and then a soak in buffer solution- this process may bring old, slow-reading electrodes back up to speed) or clean it with acetone
-You have not recalibrated in a month or so or have other reason to believe the reading has drifted off calibration. Keep strips or drops on hand to check.

By the way... two things you should be aware of. Distilled water doesn't have an ionic strength high enough for the pH to matter until after you add the nutes. FYI on that one, and you should be running calmag on your DW. Very important to return selected minerals that the plants need.

Hope that all helps a little.

 

[rrog]

Not sure which brand of pH pen you're using but the Milwaukee Tech I spoke with a few times recommended I calibrate weekly if I was taking pH readings daily. That's what I found with mine. Didn't hold a calibration well. Bought a new probe, same thing.

Finally plunged in and bought meters with corded probes. I find these hold calibrations much better.

 

[1984]

Hi and thanks to both for input. Update: I went ahead and calibrated using just the one ph 7.01 dipping. Room was roughly 25 ºc, I think the solution packet, and hence the solution itself, cold to the touch, was just under that. I'm using an old digital clock's thermometer - not the best.
OK, re Stinkyattic's comments regarding distilled water's ph inconsequence. That's interesting as these yellow tipped leaves seem to have appeared before nutes were added, ago 21 days ago. I originally thought it was owing to cramped roots so after aprox 10 days after last repotting into the 7 liter pots I added organic nute mix. The Himalaya G has gone really dark green (like my AK 47) with the yellow tips and recently part of serrated outer edges of leaves.
What's calmag? And what's a DW? (seen that around but haven't worked out what it means yet).
I haven't flushed them yet, just allowed for a fair bit of run-off to get a better reading.
The SAD read ph 6.38 and the Hima Gold 6.60. I think the ph should be lower for the HGold. I need to check. Any comments about these readings and whether they might bear any relation to the tip problem?
What's this about 'returning selected minerals'? By often using distilled water and not adding nutes on each watering (I am every other), am I not giving enough nutrition? I try to add once a week (as indicated on bottle) but this time when they should be getting nutes I didn't as I wanted 'clean' readings. Should I use the grow mix I already have (NPK = 4.50/3.00/2.70) or see about lowering/raising Ph?
I think I need to check the strains' genetics to see about what ph they prefer. Do you (Stinky) think I need to add calcium/manganese or something?
Also, did anyone check the pics in my gallery? Any ideas?

 

[stinkyattic]

Calmag is a supplement that MUST be used with distilled water (DW- this is different from the DWC you see around which is Deep Water Culture, a hydro style that depends on aerated solution), rain water, or reverse osmosis water (RO). In these water purification processes, minerals are left behind or actively removed. Too high levels of minerals can interfere with other nutrients, but your plants still need SOME, and using DW + clamag you get to 'build' the perfect plant water.
Without it, low leaves turn yellow with tan blotches, indicating calcium deficiency. This is even true in plants too young to need much in the way of 'NPK' nutes.

 

[1984]

"Calmag is a supplement that MUST be used with distilled water"

Oh my. I wish I'd known this earlier. Is this (calmag) a brand or do I just ask for some calcium magnesium mix to dilute with the DW at the groshop? I had thought about adding mineral water, but I'm loathe to add things if I don't know why I'm doing it so end up not adding anything unless I think I know what I'm doing. I'm going to take your advice because as you say...

"your plants still need SOME [trace elements/minerals], and using DW + clamag you get to 'build' the perfect plant water.
Without it, low leaves turn yellow with tan blotches, indicating calcium deficiency. This is even true in plants too young to need much in the way of 'NPK' nutes."

This has happened although I had put it down to early leaves getting their nitrogen and sugars used up by later new growth. I don't cut off any affected leaves unless they touch the soil. At the moment lower leaves aren't much affected and I think I'm in time to correct the calmag def, which is the message I'm getting. Do you think the leaf tip yellowing at upper leaves (and then browning) is caused by the same def? It would make sense wouldn't it? Particularly after having just glanced at the sticky re sick plants.
My nute mix includes cal and mag at low levels of 0.40%. Is this OK or should I ALWAYS add calmag when watering? I mean should I also use it when watering future cuttings?
BTW, big thanks StinkyA.
Rrog, thanks too. I don't know the brand name, it hasn't actually got one. It's a pen type thing probably manufactured in China.

 

[1984]

UPdate: I couldn't get my hands on any calmag this morning so I carried out a little experiment. With one, at about mid day, I used 50/50 distilled and a weak mineral water + nutes. With the other, I used 50/50 distilled and tap water that had been sitting out a few days + nutes. The idea is that the mineral water contains highish trace levels of calcium and magnesium as well as other trace elements such as zinc. I am also presuming that the tap water will also contain trace elements. It's not perfect but looking at them tonight 9 hours later the leaves have responded more than previously using oly the distilled. That's kind of interesting. I'm also aware that the nutes also carry cal and mag (and other trace elements) but I'm guessing not in sufficient amounts as the last watering but one carried nutes yet didn't effect any perceivable changes in the supposed calmag def. When possible I'll get the calmag and see what that does on the 3rd and last plant suffering the same symptoms.
Thanks for your help.

 

[stinkyattic]

Careful with 'mineral water', since there could be a significant amount of sodium in it.
CalMAg is made by Botanicare and has the correct ratios of minerals for cannabis.
Good luck.

 

[1984]

I'm off mineral water now (only used it once) because I got a calcium magnesium nitrogen mix specifically made for mj. Although it says on the bottle that it shouldn't be used with DW with a ph under 5. Mine is just 5. Why is this? Should I continue or switch to tap w?

 

[stinkyattic]

I have no idea why that would be on the label. As I said earlier in the thread, distilled water doesn't have an ionic strength high enough for the pH to matter until after you add the nutes. Or it shouldn't anyway, if it's really pure enough!
Why were you using DW in the first place? Is your tap water REALLY all that bad? In soil, tpa water is almost always fine!

 

[1984]

Why am I using DW in first place? It was a 'growshop' recommendation. They said that while tap water can have the chlorine evaporate thru leaving it exposed to air for 24/48 hours some heavy metals or other non desirable elements remain.
Are you suggesting I should switch? I'd be happy to as DW is expensive.
I'm not sure I understand how to correctly read pH anyway so I'll be posting some questions about this later (need to go to work now). Last night I watered them with tap and DW 50/50 plus the calmag mix I mentioned. The pH reading was 8.5. I am considering adding lemon or lime juice at next watering. Any comments on that stinkyAtt? Thanks a lot for your input Stinky. Much appreciated.

 

[toodles]

Go read up on Organics. Read the StickyNote on Organics for beginners.

IMO the various forms of hydro are not for beginners, especially those who know nothing about basic chemistry.

That is **MY OPINION**, and it is not going to be shared by all around here.

You could transplant those to a good organic soiless mix and they will be off and growing like mad in no time. I have done it. I know it can be done.

An organic soil grow requires much less attention than a hydro grow...if you do your homework, make a grow plan, and get started right. And there is plenty of help in the organics forum.

PLAN your grow though.

Toodles


EDIT ADD:

I didn't read thoroughly the first time.
Sorry, too late to transplant. Do a organic soil grow next time.

 

[maryj315]

Careful with 'mineral water', since there could be a significant amount of sodium in it.
CalMAg is made by Botanicare and has the correct ratios of minerals for cannabis.
Good luck.

That is a good piece of information to have when selecting bottled water


THANKS STINKY

 

[bounty29]

I played with distilled water, thinking it'd be better because I was starting with a clean slate. The headaches I got from trying to figure out the correct dose of CalMag and the unstable PH of distilled water weren't worth it. I haven't used CalMag in a loooong time, and I just let my tap water sit out for 24+ hours before I use it.

 

[1984]

Nice to get more input. My grow WAS planned but there's only so much you can take in from constant reading. Besides, there are a lot of contradicting ideas out there/here. I've seen people wait months before attempting anything in order to get everything just right and then get their crop wiped out for one unforeseen reason or another. The way I've gone ahead is, having read up what I think is a reasonable amount, get on with it and learn through mistakes. Mistakes are an unavoidable part of any learning curve, no mistakes, no learning. Besides, the way I reckon, if you don't get some disaster you will end up with something worthwhile. Right now I have a nice flowering AK 47. I don't like the Himalaya G's much, they look like an outdoor plant to me. The other hybrids I'm using are well suited to my climate and indoor growing (short and stocky with good body growth).
Right now I might drop DW but I want to wait because Stinky has said something to the effect that a 'perfect water solution' can be obtained using DW + 'calmag' - if I got that right. So I'm waiting to hear from him about this. For now I might switch to just tap w once symptoms disappear.
No one said anything about the lemon juice to lower pH ...?
Plants have been vegging too long - they're between 40 and 53 days old. I need to take some cuttings tomorrow and switch to 12/12. Question: can you take cuttings when u switch light schedule to 12 12 before they actually start to flower? I mean like in the first week or so in 12 12. Is that doable?

 

[stinkyattic]

Sure you can. It means letting them veg longer to recover and return to a vegetative growth, but there's something to be said for taking advantage of the large number of undifferentiated cells being produced when the plant is switching gears into flower mode! IT has been noted that strains known for being difficult to clone often respond well to cuts being taken in the first 1-2 weeks of flower.

Distilled water is not technically as clean as RO water since during the evap/condense process it is exposed to atmospheric gases, whcih do go into solution, but if your DW is good then yes, you can build yourself a good base water from that and calmag, on which you add the nutes. Generally tap water is fine in most applications, but if yours is really bad, then building a DW + CalMag water is worthwhile. Only you know how your tap water is. Oh- and lemon juice, while functional in emergencies, is far from ideal, as citric is a weak acid, and will not only require a LOT, but will not keep pH stable over time as well as a strong acid (phosphoric is ideal but nitric is passable as a substitute in veg at least) which adds the H+ ions you are after.
BTw I'm a chick

 

[FreezerBoy]

Are you suggesting I should switch? I'd be happy to as DW is expensive.

Distilled water is dead water. There's nothing in it but wet. Your nutes intentionally lack essential elements they expect you to supply with tap water. They even make special hard water formulas; Double extra lacking. Now what would you pay?

If you can't use tap, go RO and get some CalMag. Pro units run $100-$300. Here's a DIY that looks interesting DIY RO Filter

FB

 

[rrog]

I'm a little confused. Many manufacturers of nutes have ratios or formulas for growers using hard water, and those of us using RO or distilled. So there isn't the basic assumption that all users of nutes are starting with tap water, which is wildly varied across the globe. Some very hard, and some very soft.

Secondly, nutes have CA and MG, so it seems that using CalMAg in a proper nute solution is unnecessary. As I said, it seems that way, unless I am missing something?