ProMix pH: Runoff Or Water-Nutrient Mix?

[startergrow]

Hey guys

I'm new to Promix (and soil grows) and think I may have a PH issue stopping nutrient uptake. The plants are kind of a side project of some sad clones, from an old Mother, that I want to bring back to make seeds. I have some feminized pollen from an earlier clone. The strain is Cheese.

I usually use DWC for my plants.

The mix is about mostly Promix BX M (which has perlite & vermiculite), some extra perlite and a little dolomite. The light is a Mars TS2000.

I've definitely over watered with the last soaking, as I wanted to make sure it was getting nutrients as the bottom leaves were yellowing. I used a Root Farm A+B nutrient that works fine in my DWC. PPM was about 500. PH of the water with nutrients was 6.5.

I think there's enough nutrients in the water but the plant doesn't seem to be getting any.

So, to achieve proper PH, do I make sure the water being used is at a proper PH or do I need to measure run off for what it becomes after hitting the soil?

Appreciate help from anyone.

 

[farside05]

Hey guys

I'm new to Promix (and soil grows) and think I may have a PH issue stopping nutrient uptake. The plants are kind of a side project of some sad clones, from an old Mother, that I want to bring back to make seeds. I have some feminized pollen from an earlier clone. The strain is Cheese.

I usually use DWC for my plants.

The mix is about mostly Promix BX M (which has perlite & vermiculite), some extra perlite and a little dolomite. The light is a Mars TS2000.

I've definitely over watered with the last soaking, as I wanted to make sure it was getting nutrients as the bottom leaves were yellowing. I used a Root Farm A+B nutrient that works fine in my DWC. PPM was about 500. PH of the water with nutrients was 6.5.

I think there's enough nutrients in the water but the plant doesn't seem to be getting any.

So, to achieve proper PH, do I make sure the water being used is at a proper PH or do I need to measure run off for what it becomes after hitting the soil?

Appreciate help from anyone.

Pro-Mix is a buffered medium. You do not need to be concerned with the pH of your nutrient solution going in and do not attempt to measure the pH of the runoff. How much of each of the Roots products are you using? Although total ppm's are commonly thrown around, it's an arbitrary meaningless number. At this point you should be more concerned with how much of those ppm's are coming from Nitrogen, and at this stage of their growth I'd say somewhere between 90-120 ppm should be from N.

 

[startergrow]

Good to not have to be too concerned with PH.

Just checked farside, and I realized I messed up. I must have got confused last couple of waters and have been giving it the flower mix by mistake.

The flower nutrient list the ratio as A: 4-0-1 and B 1-4-7 ( They've been getting this for the last week or so by mistake)

The usual veg nutrient is: 2-0-2 and 0-1-3

I'm adding equal amounts of both. Am I right if I add the ratios so get:

• 5-4-8 total with flower and
• 2-1-3 with the veg nutrient?

 

[farside05]

OK, I see 4 products on Root Farms website, Base, All-Purp, Veggie, & Bloom. You can see each in the table below:

Root Farm Products.jpg

• farside05
• Sep 23, 2021

Not sure where this "The usual veg nutrient is: 2-0-2 and 0-1-3" comes in since I see no products representing those numbers.

Now assuming you were feeding 1.5 tsp of the Base and Bloom (really it wouldn't make too much difference if it was Base and All Purp since the All Purp and Bloom products are very similar), the elemental breakdown is as follows:

Root Farm PPM.jpg

• farside05
• Sep 23, 2021

Do you see a problem above? Although N, P, K, Ca, Mg, & S are covered, and probably adequately for this stage of growth, the Root Farm products are completely void of all the other micro nutrients. Being that Pro-Mix is a blank canvas with no other nutritional value, I would fully expect to see a bunch of deficiencies using this fertilizer with that growing media. I would expect the same problems in DWC too with the Roots lineup since plain water is not going to contain all those other micros.

One other point. Your original post said "The mix is about mostly Promix BX M (which has perlite & vermiculite), some extra perlite and a little dolomite." I can see adding some extra Perlite to the BX. An extra 10% Perlite is what separates Pro-Mix BX from Pro-Mix HP, but adding Dolomite Lime may not be the best idea. Pro-Mix already contains lime and is balanced at the factory to a pH of 5.8.

In summary, I see your problem as 2 fold. 1) you need a "complete fertilizer" that contains all the elements for a successful grow, and 2) depending on how much "a little dolomite" is, you may have thrown your medias pH too far out of line.

 

[Phytoplankton]

Problem I see is mostly the overwatering. Cut back on the water and I think many of the issues (yellowing leaves) will resolve themselves. Might need a little more N. Also dolomite takes a while to become available to the plant, so a little calmag might help too.

 

[farside05]

Also dolomite takes a while to become available to the plant, so a little calmag might help too.

The fertilizer applied provided 109ppm of Ca and 34ppm of Mg. That's way more than sufficient. Adding more would be of no benefit.

 

[Phytoplankton]

The fertilizer applied provided 109ppm of Ca and 34ppm of Mg. That's way more than sufficient. Adding more would be of no benefit.

Good catch, I missed that!

 

[bobrown14]

Since your growing in a soil-less medium (Promix is soil-less without well soil organic matter), my suggestion is to follow the directions for pH that are on the label of your fertilizer.

It's important to read labels and follow directions to the TEE when using fertilizers and other chemicals for whatever reason.

 

[startergrow]

Thanks farside for the great breakdown.

It would seem the nutrient I am using is not sufficient. It isn't what I usually use but unfortunately the local hydro shop I usually go to, was shut down for months because of Covid restrictions and I was left with only the big box stores which only had a very poor selection here.

The dolomite seems to be a mistake too. luckily I did not add much.

I really appreciate you going in to the breakdown of the elements. I've never thought it through that much but I'm going to start. I'll watch that closer from now on.

Phyto you're right about over-watering. I knew I was, but panicked in trying to get the plants nutrients.

Based on the great advice above from all I am going to let the soil dry out a bit. The plants are planned to go in to a larger grow bag at some time so I'll move that up a bit and use straight ProMIx.

I'll also look in to a new, more complete nutrient mix, to start with the next water.

Thanks so much for all the help. The plants are photo so I have time to bring them back. I'll update in a bit after some time to let the changes take affect.

 

[farside05]

Thanks farside for the great breakdown.

It would seem the nutrient I am using is not sufficient. It isn't what I usually use but unfortunately the local hydro shop I usually go to, was shut down for months because of Covid restrictions and I was left with only the big box stores which only had a very poor selection here.

The dolomite seems to be a mistake too. luckily I did not add much.

I really appreciate you going in to the breakdown of the elements. I've never thought it through that much but I'm going to start. I'll watch that closer from now on.

Phyto you're right about over-watering. I knew I was, but panicked in trying to get the plants nutrients.

Based on the great advice above from all I am going to let the soil dry out a bit. The plants are planned to go in to a larger grow bag at some time so I'll move that up a bit and use straight ProMIx.

I'll also look in to a new, more complete nutrient mix, to start with the next water.

Thanks so much for all the help. The plants are photo so I have time to bring them back. I'll update in a bit after some time to let the changes take affect.

I can give you a link to the spreadsheets I use for my calculations, plus I've used a a number of different nutrients with Pro-Mix and can make recommendations there too if you are interested. If you're up-potting, you can also check my thread on how to make your own Pro-Mix, aka Faux-Mix®, which is linked in my signature.

 

[startergrow]

Thanks farside. I looked at making the Faux-Mix. Makes a lot of sense as I already have some lime and perlite.

It would be nice to know what exactly is in the "soil" I'm using. It's part of what I like about DWC, knowing what is being added, which is usually what I do.

It'd be great if you have some recommendations for nutrients. I'd like to learn more.

Appreciate you taking the time.

 

[startergrow]

In thinking about it, what do you think a good range of nutrient elements for veg and grow?

I guess it would vary somewhat between strain and growing situations but there's probably a good mid point.

Here's a chart I found (Cannabis Business Times Nov 2020)

 

[bobrown14]

IF you wanna grow in soil only... Coots mix FTW.

 

[Beak]

Thanks farside for the great breakdown.

It would seem the nutrient I am using is not sufficient. It isn't what I usually use but unfortunately the local hydro shop I usually go to, was shut down for months because of Covid restrictions and I was left with only the big box stores which only had a very poor selection here.

The dolomite seems to be a mistake too. luckily I did not add much.

I really appreciate you going in to the breakdown of the elements. I've never thought it through that much but I'm going to start. I'll watch that closer from now on.

Phyto you're right about over-watering. I knew I was, but panicked in trying to get the plants nutrients.

Based on the great advice above from all I am going to let the soil dry out a bit. The plants are planned to go in to a larger grow bag at some time so I'll move that up a bit and use straight ProMIx.

I'll also look in to a new, more complete nutrient mix, to start with the next water.

Thanks so much for all the help. The plants are photo so I have time to bring them back. I'll update in a bit after some time to let the changes take affect.

It looks like the pot you have them in now is to big already. Your media will take forever to dry out and you are drowning the plants and starving them of oxygen. Roots grow straight to the bottom of the pot and move up from there. I your pot is to big you will drown and kill the roots trying to make it back up to the top. So if you start plants in solo cups until seedling or clones gets 3 nodes and then move up to a one gallon pot from there until plant gets 6-7 nodes. This way when you transplant in your final pot you will have a good mass of roots to fill the bigger pot. If you dont do it this way you could have all your roos at the bottom of your final pot and the middle of the pot wont have may roots at all. After you harvest, tear you media apart and see if this happenrd.

 

[Bill284]

It looks like the pot you have them in now is to big already. Your media will take forever to dry out and you are drowning the plants and starving them of oxygen. Roots grow straight to the bottom of the pot and move up from there. I your pot is to big you will drown and kill the roots trying to make it back up to the top. So if you start plants in solo cups until seedling or clones gets 3 nodes and then move up to a one gallon pot from there until plant gets 6-7 nodes. This way when you transplant in your final pot you will have a good mass of roots to fill the bigger pot. If you dont do it this way you could have all your roos at the bottom of your final pot and the middle of the pot wont have may roots at all. After you harvest, tear you media apart and see if this happenrd.

Good morning @Beak
Welcome to 420Magazine my friend.
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Thanks for pitching in with the advice.
Unfortunately that's an old thread and you may mot get a response.
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Bill284

 

[seaofgreen18]

Hey guys

I'm new to Promix (and soil grows) and think I may have a PH issue stopping nutrient uptake. The plants are kind of a side project of some sad clones, from an old Mother, that I want to bring back to make seeds. I have some feminized pollen from an earlier clone. The strain is Cheese.

I usually use DWC for my plants.

The mix is about mostly Promix BX M (which has perlite & vermiculite), some extra perlite and a little dolomite. The light is a Mars TS2000.

I've definitely over watered with the last soaking, as I wanted to make sure it was getting nutrients as the bottom leaves were yellowing. I used a Root Farm A+B nutrient that works fine in my DWC. PPM was about 500. PH of the water with nutrients was 6.5.

I think there's enough nutrients in the water but the plant doesn't seem to be getting any.

So, to achieve proper PH, do I make sure the water being used is at a proper PH or do I need to measure run off for what it becomes after hitting the soil?

Appreciate help from anyone.

Howdy I'm a long time pro mix user! umm, did you amend it first? There's nothing in it! I use worm casting's and KIS nutrient mix on top of my scheduled nutrient feeding I have GREAT RESULTS and I reuse it in a no till application Ron from Michigan