Need help with nutrient lockout

[faceto27]

You'd be amazed how much abuse these plants can take. Drill some holes in your pot, sides and bottom, to improve the drainage then flush with pH adjusted water until your runoff comes out where you want it. Water with 1/4 strength nutes.

Priests can't help plants - it all has to do with the birth control issue. You need to get naked and dance around your grow room while waving ostrich feathers. It's the only metaphysical treatment that really works.

PC :smokin:

Okay, just finished dancing, havn't gotten dressed yet, so forgive me while I type in the buff.

There is still one big problem to resolve though. What is the ph level that I should be using for watering/nutrient intake??

Do I treat it as soil, and go for 6.5 thereabouts? Or do I treat it as soiless, and every reasearch that I can find, says that for Promix, it is soiless, and the ph level should be about 5.8.

Its a big difference. I flushed yesterday with the ph adjusted to 5.8, but its too early to tell if that is the way to go. But in the next couple of days, it will be watering time for all the plants, and I really need to figure out, what level the ph should be with a Promix based soil medium. Where I bought the Promix, the dude said, to go 5.8, and nutient intake every watering, but only use 1/2 (10ml) as opposed to the normal 20ml per 8 litres of water.

I understand your more of a hydro guy, but if you know the answer to this riddle, please do tell.

:smokin:

[prairieplantsystems]

How does pH have anything to do with how strong your nutrient solution is?

The nutrients are absorbed depending on your pH level. If you have a very high EC solution but the pH is not optimal the plants won't absorb as much nutrient. The same high EC with the optimal pH will permit the plant to absorb the nutrient at a much higher level, but you run the risk of running into nutrient burn. Ideally you need an optimal pH and a nutrient solution with an EC just under the level of nute burn. The level of EC can be quite tricky to work out, since for a period of time (i.e. a couple of weeks) your EC can be higher that the level that causes burns without burning the plants, since they are stocking nutrients in the stems, leaves, buds etc. Eventually the plant material becomes saturated with nutrients and if you maintain an EC level as high as you did before the leaves will start burning.

This is for hydro, for soil the same principles apply, but they are harder to control precisely since the soil will buffer against quick variations of the EC or pH level.

[faceto27]

:thumbsup:

Okay, I believe I have finally found the answer to the ph in soiless medium. The followinhg link is report from Ohio State University, and they do confirm that for soiless media, the ph level needs to be maintained between 5.7-6.4. Otherwise micronutrients and potassium lockouts occur.

Micronutrient Disorders, HYG-1252-98

[Weedhound]

Oh please.....and what did I say.....6. I need to grow another arm to pat myself on the back.

[faceto27]

Oh please.....and what did I say.....6. I need to grow another arm to pat myself on the back.

Give yourself a pat on the back.

Should get Stinky to post that in her noobie guidelines. Otherwise, people will make the same mistake as I did.

This is what is posted on one of the websites that sells Pro-mix.

"Promix also contains agents to stabilize the PH levels (measure of acidity) at 5.5 to 5.7 thus eliminating the problem of adjusting PH levels of the water which is crucial to indoor growing.



In other words, so long as you use Promix you do not have to understand anything about PH .. or EC or PPM. In fact all you need to know is that when the plants go dry, you need to add some food to the bucket of cold tap water and feed your plants. Fairly easy I think."

That is soooooo wrong. If you put water in there that is ph 8.0, the prom-mix stabilizing agents are going to bring it all the way down to 5.7 ????? No way.

I have a dying plant as proof, and 3 in the infirmary recuperating from spending the past 2 days in Extensive Care.

[gainesvillegreen]

The nutrients are absorbed depending on your pH level. If you have a very high EC solution but the pH is not optimal the plants won't absorb as much nutrient. The same high EC with the optimal pH will permit the plant to absorb the nutrient at a much higher level, but you run the risk of running into nutrient burn. Ideally you need an optimal pH and a nutrient solution with an EC just under the level of nute burn. The level of EC can be quite tricky to work out, since for a period of time (i.e. a couple of weeks) your EC can be higher that the level that causes burns without burning the plants, since they are stocking nutrients in the stems, leaves, buds etc. Eventually the plant material becomes saturated with nutrients and if you maintain an EC level as high as you did before the leaves will start burning.

This is for hydro, for soil the same principles apply, but they are harder to control precisely since the soil will buffer against quick variations of the EC or pH level.

You took my quote out of the context of it's paragraph. The question was to make a point that the company's claim that because the pH is 'stabilized', you do not need to monitor the PPM of your nutrient solution whatsoever... which is completely false.

[Dutch Pimp]

I'm gonna stick this chart in ph related threads...:jointsmile:

[PharmaCan]

I'm gonna stick this chart in ph related threads...:jointsmile:

Hey Dutch Pimp - I got your pm's here and there. Too soon to rep you again here and not enough posts to reply at the other place.

Good chart, BTW! :thumbsup:

PC :smokin:

[faceto27]

has anybody else had any trouble with their ph using soiless mix?

[cjus44]

If you put water in there that is ph 8.0, the prom-mix stabilizing agents are going to bring it all the way down to 5.7 ????? No way.

Yes way... I've been using Promix HP for 3 years and I have yet to put any kind of solution into it that hasn't come out within 5.8 - 6.2 range. (Haven't tried as high as 8.0 yet, but 7.5 has never given me any problems.)

How are you measuring the pH, with a meter? Is it properly callibrated everytime you use it?

Promix is a "soiless" medium and the pH range should be kept at around 5.8-6.0. And, yes, in most situations you don't have to bother with the pH (EC is a must in any situation though). Though if you really are reading runoff in the high to mid 6's then you should definitely try pH downing (obviosly try one plant first.)
Believe me, as helpful as these (and similar) forums are there seems to be a general lack of understanding of Pro-mix and related media.



I have had problems of my own recently that sound very similar to those that you are describing: yellowing and burning leaves that seem to come around week 6-7 in the plants life. I have yet to pinpoint the problem exactly, but here are my conclusions so far after 4-5 crops with the same problem :

1. Originally thought that it was just nute burn, but I've gone down to a 1/4 of my orignal doses (different crops) without improvement. In fact the latest batch now have many definite signs of nute def.

2. Investigated the pH possibility but have always found my pH in the correct range.

3. Have tried monitoring EC levels, and have mostly maintained those in and around what is considered optimal for weed. Though as I said nute doses were lowered so the EC has been kept lower for the latest batch. Doesn't seem to be the problem either, though I definitely have to work with this more.

Given the above I've gone right back to the source and re-looked at my tap water. I've noticed this winter that the pH has crept up from the usual 7.0 - 7.2 range to about 7.3 - 7.4. Like I said, with Promix pH should not be an issue, but this definitely indicates that something in the water has been changing, most likely the mineral content. Given that I'm constantly scraping calcium deposits off my humidifier I'm fairly certain that my water has increased in Ca over this winter.

I did some research into Ca and found that too much Ca can lock out (magnesium) Mg. I then compared my symptoms to Mg def and they seem to be a perfect match. This is a fairly recent conclusion so I have yet to test it. You mentioned that the pH of your water is around 7.3, maybe you are having similar problems? If not Mg than perhaps you have too much of some other mineral? I know that too much Ca affects Fe (Iron) uptake as well.


Anyways here some tips for Pro-mix; I've had great success with it before (using GH FloraNova series):

1. Soak it everytime you water, feed or no feed. You should aim for about 25% run off.

2. Fert salts can build up quickly in it so once you get to bud, leach with plain water every other watering for sure.

3. Don't use ferts when transplanting them to larger pots. Transplant then give straight water; feed next time (and then alternate if in bloom).


Would attach some pics of my symptoms, but can't figure it out in this forum yet.