Promix + high alkalinity water

Hey guys,

I'm having an issue here. Recently i started growing in Promix HP in 3 gal buckets. Things were going great but ive had some challenges lately. Ive had a bit of heat issues and while i was away my wife added another fan to the room which was blowing right on the plants and they were not enjoyin it. The room got up to 30C for a week and the added wind dried them out a bit but they have bounced back now that i added cool fresh air from my crawl space and moved the fan so its not blowing directly on them.

Ive been quite lightly with plant prod 20-20-20 1/3 (recommended dose) every 3rd watering but i flushed them good anyway thinking that my ph was off not allowing the plantd to take certain nutrients csusing a buildup. My city water's alkalinity is like 180 CaCo3/L so ive gad to add about 3 cap fulls of ph down to grt my water from 8.3 to 5.8. I think i may have aciified my promix by adding so much ph down or toxified it with phosphorous from adding so much ph down (phosphoric acid).
The plants have the claw look on some older fan leaves and they arent growing very vigourously right now. I added a bit more dolomite lime as a top dress about 4 dsys ago and they look a bit better so im thinking thst i will not ph adjust my next watering and see if some of the carbonates help bring my substrate ph back up.

Do i need RO water with an alkalinity of 180 in my tap water?
Am i even on the right track?

Im used to growing in organic soil mixes and watering with lake water but switched to soilless because i dont have access to lake water in the winter.

Any advice?
Am i over thinking things and it was all just the stress of the heat+windy enviroment?

I will add pics once i get home and can take some pics for you all.

Are you leaving your tap water out in buckets at least24 hours to gas off chlorine etc?

Check your runoff water ph. I found the same with my promix...it was low ph.

If your feeding only every third watering could they need more minerals and nutrients?

I always say fix ph first....wrong ph usually points to multiple deficiencies and symptoms and makes it hard to diagnose.
I tested my water ph.....soaked a handful of the promix in a glass of same water for a few mins....then squeeze some of the medium into the glass and test the ph again. (You may have to strain out the solids if your testing with drops.) This difference in ph gave me an idea of where to start adjusting ph. I found it VERY low.

I also tried swinging the ph real high (like your water) to compensate BUT the rapid ph swing really stresses the girls bad. Especially in a soiless mix which does only slight if any ph buffering.

your over thinking it.get some pics up I may be able to help

So i took a media sample from the plant that looked the worst. 7.8 in distilled water.
Im pretty sure the bicarbonates in my tap water is responsible for this.. After letting my water sit for 24 hours the ph sits at 8.3. I use alot of phDown (phosphoric acid) to bring it down to 5.8 before watering my plants but maybe i have to take the ph lower with more acid to reduce the bicarbonates..

All I know is that i started using 50:50 RO:Tap and gave an iron chelate foliar and things are looking better for now. The clawed leaves have mostly flattened back out and look better but i know that this isnt going to last unless i can get the medium ph down where it should be.

Seriously considering giving a flush with some 4.0 water to try nuke the bicarbonates.

Fuck, i dunno lol

Have a look

Looks over watered

canadiankushman said:

Have a look

Click to expand...

Do any leaves have a paper fill to them or are they firm?

u need to do something about u water.i use lots of pro-mix best water for me rain water in winter I melt snow.pro mix has plenty of lime init.good thing about pro-mix is very easy to flush

Yeah some leaves are feeling kinda paper like.
I do like the promix but I need to make some changes.
Im going to use 100% RO for the next few waterings then switch to 50:50 tap:RO

They are 3' plants in 3gal containers. They use up water pretty quick so i feed lightly but often and flush good once a week.

But in doing this im turning my promix alkaline from the bicarbs in my water.

Or, im adding so much PHDown that im over feeding the plants Phosphorus which could also be causing a high ph situation.

I also find that my plants leaves commonly point down like that due to my vertical bulb. Its the cupping and spotting that im concerned about most.

Ive taken all of my clones from these plants and im going to flower them soon. I hope i can get them in order fairly quickly.

Get new nutes also. 20-20-20 is not even close to the ratio you need to be using. Do a search on nutrients and look at the ratios. Then do some research on the plant you're trying to grow. Use the gained knowledge to pick something more friendly to weed. My grow nutes have a 7-9-5 ratio. The numbers on the fertilizer means something. And higher numbers aren't always better. It's the ratio of one to the other that matters. The other thing is when using pro mix you need to understand that there is nothing in the medium that is food for the plants. So if you only feed it every third time you must give it enough food for the other 2 waterings.

Yes less can be more. But not enough is not enough. I've been using pro mix for years. Some say feed feed flush. That's very popular around here. Never flush flush feed. The only time flushing is needed is when you over feed AND/OR you lock up the soil. Over feeding should NEVER be the goal. The goal is to feed every watering with ONLY enough food to last until the next watering. This will take time to learn. Once my cutting or seedling can handle nutes they NEVER get straight RO water until the end of the plants life. The last 2 waters ONLY. I can do this because even though I'm not flushing I'm also not allowing salts to build up either do to using to much fertilizer.

So would adding 9ml/5gal of ph down (to get me at 5. give my medium way too much phosphourus?

I have other nutes, im just kinda experimenting with this plant prod stuff.

I have 2 other kinds of 3 part hydro nutes to use and im going to switch once i flush them out with good water and get them bent in shape and ready to flower out.

Maybe to clarify for us Ckush...are you usin Pro-mix potting soil or Pro-mix soiless? There is a HUGE difference between the nutrient needs of your plants depending. Maybe you said and I missed it. I use Promix soils in all my grows....I use a mix of their bags...I combine the vegetable compost...and potting soil together...ithink the bags are green and white and blue and white. They have myco fungi to aid in root development and nutrient uptake and should feed for 2 to 3 months.
If its a soiless mix then you are solely responsible for providing the nutrients through your watering regimen. So... if using RO or flitered water...no or little nutes...plus soiless equals PROBLEMS.

Keeping in mind PH outside of known acceptable parameters in either scenario causes nute lockout and deficiencies regardless.
Does that make sense bro?

canadiankushman said:

So would adding 9ml/5gal of ph down (to get me at 5. give my medium way too much phosphourus?

Click to expand...

You don't measure how much up or down you add. You just add as much of the correct one to make the PH of the nutrients move to where you want it. With pro mix you want to be at 6.5 not 5
There is also concentrate and diluted PH adjusters. I use concentrated PH up and diluted PH down. Because I have to move much further up than I ever do down. I suggest diluted for beginners.

Dude, you don't need to ph your water for promix - it does that all by itself. Adding all the extra things you have been is not good, but luckily most things flush out of promix with a good few days of waterings. The picture you gave doesn't even show any signs of ph problems.

You should also feed every time you give the plant water since promix doesn't retain nutrients. Promix should never be allowed to dry all the way out - it should go from wet to damp. As someone else once told me - dry promix has the nutritional value of dried cardboard. In a 3 gallon, you will have to water at least once every day during flower.

Your plants look underwatered and underwatered plants will show all kinds of deficiencies if you don't get them back on track.

1. By the Pro-mix in 3.8 cu. ft bales (or Sunshine Mix) at most garden centers. Add 3.5 cups of dolomite lime to the mix, along with more perlite (2 cu.ft)......that mix will fertilize for about 10 days, then start adding at low doses and raise slowly.

2. By an r.o. device...you can get a good 3 or 4 stage device for $125-175 and it will eliminate your high ph problem. Bad water if often a problem for many.

3. By a good nutrient made for marijuana by AN or Botanicare or Canna or the 100 others. These are complete fertilizers and the veg/bloom nutes are in the right proportions. 20-20-20 is great for tomatoes and not much else.

4. By some Cal/Mag which you'll need since you are using an r.o. system and add with every watering. This is necessary since the r.o. device removes these. I go 10 ml per gallon.

5. Buy a good pH/ppm meter to monitor your ph and fertilizer levels. It's important if you want healthy plants. All water/nutes going into promix should be within 6.3-6.5 pH, never higher.

So many things are wrong right now, it's best to start over, buy the right supplies and move forward properly. Your issues most likely will only continue to get worse as you toxify the soil with the wild pH swings- pot likes things at a consistant level, not up and down and all over the map.

As I've said in many threads, there is nothing cheap about growing pot- it's costs a bit to get up and growing right. But in the long run, it will give you the best chance of ending up with something worth smoking.......

I'd suggest you buy a book. You can get this online used for cheap. It's an easy read and covers all the basics. You might not even need to read most of it. But if you look at the chapters or flip through and glance at the things you don't know and read those sections it will help. Marijuana grower's insiders guide.

There are things being said here that are not correct.

Unless you are keeping mothers for a long time no need to add lime. Over a long period of time added lime is beneficial. BUT most people are done with the plant before the peat moss starts breaking down. That's when the lime is helpful.

The lime ISN'T added so you don't have to PH nutes but for when the peat moss breaks down. It's still a buffer though.

ALWAYS check the PH and adjust to 6.5.

Don't buy a cheap PH meter and research and check reviews because good ones aren't cheap. I recommend blue lab combo meter. And keep the receipt it has a 5 year warranty.

R/O filters are great to solve your water problems.

Don't listen to any specific amount that someone may tell you. Unless you're using the EXACT same product. 20 mls of one product will most certainly contain different quantities than another brand. So pay attention to what you're using. Not quantities you're reading online. That's why I try not to be to specific.

I see guys running PPMS over 1000. If I did that with my nutes my ladies would be burned to a crisp in just a few days.

As you've noticed you are going to get differing points of view. And if you don't have some knowledge how are you going to know who's advise is going to help or hurt. Some won't hurt but sure is a waste of time for most people.

GOLDBERG71 said:

I'd suggest you buy a book. You can get this online used for cheap. It's an easy read and covers all the basics. You might not even need to read most of it. But if you look at the chapters or flip through and glance at the things you don't know and read those sections it will help. Marijuana grower's insiders guide.

There are things being said here that are not correct.

Unless you are keeping mothers for a long time no need to add lime. Over a long period of time added lime is beneficial. BUT most people are done with the plant before the peat moss starts breaking down. That's when the lime is helpful.

The lime ISN'T added so you don't have to PH nutes but for when the peat moss breaks down. It's still a buffer though.

ALWAYS check the PH and adjust to 6.5.

Don't buy a cheap PH meter and research and check reviews because good ones aren't cheap. I recommend blue lab combo meter. And keep the receipt it has a 5 year warranty.

R/O filters are great to solve your water problems.

Don't listen to any specific amount that someone may tell you. Unless you're using the EXACT same product. 20 mls of one product will most certainly contain different quantities than another brand. So pay attention to what you're using. Not quantities you're reading online. That's why I try not to be to specific.

I see guys running PPMS over 1000. If I did that with my nutes my ladies would be burned to a crisp in just a few days.

As you've noticed you are going to get differing points of view. And if you don't have some knowledge how are you going to know who's advise is going to help or hurt. Some won't hurt but sure is a waste of time for most people.

Click to expand...

I actually found out there is no need to ph water going into promix from a guy named homebrewer - you should check out his grows.

if you need a ph meter, i have used an etekcity high .05 accuracy ph meter for a year and have never had a problem with it's reading. i store it in some 4.0 solution and only need to calibrate it by at the most .04. It was $20 - so don't buy all the hype.

SamsonsRiddle said:

I actually found out there is no need to ph water going into promix from a guy named homebrewer - you should check out his grows.

Click to expand...

I know him. I find it hard to believe he would tell you not to PH unless he knew you were close. But it doesn't change my point of view either way. Good guy though. He helped me a few times. We use the same nutes. If it's close I'd agree. I can only speak for myself and my flower nutes when mixed are down in the 5s and there is absolutely no way I'm not raising it. To me it's simple if it's not in the right range the plant won't get it. So if I put it in right it's accessible from the moment I put it in. There's no buffing needing to be done first. I'm not leaving something that important to chance.

I'm also not adding any lime. I've tested that myself. I've added more D lime to buff. I've also added hardwood ash to bring the pro mix starting PH of the soil to 6.5. I've compared the result to doing nothing but cutting it with perlite. And I no longer waste my time with either and my results have never been better. My knowledge and familiarity with my nutes has gotten better as well. And that is what I should have been paying more attention to.

Now that I don't read labels and follow schedules. I have zero problems because I mix bloom and grow nutes to get better ratios. Because this was where the issue was I was trying to solve. Then I realized that pro mix has a PH of 5.7/5.8. So I cued into that as my problem. Because PH is so very important. Only to come full circle tight back to opening the bale and mixing it with a bag of perlite.