4th grow in Promix - I still suck - Help

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****** UPDATE *******

Hey ProMix growers. I'm updating the original post to condense the most useful information from this thread in one place for an easier read.

My problem:
I was growing in Promix (NOT HP OR BX - but the small bags that are labelled "Seedling starter" and "Potting Mix". Both of these have nutrients already in them and retain water VERY differently than HP or BX. I had been watering them at a PH of 6.2 since their inception and over time the medium became more and more acidic to the point where I was suffering from lock outs of many elements, mostly Mag (Rust spots, lime green new growth, slow growth, purpling of stems). I had been treating THIS promix the way I've been reading growers treat heir HP and BX promix. Big mistake. Eventually my runoff was getting so low that the plants were on their way out. I really wanted my runoff in that "optimal" zone (6.3-6.8).

Solution:
Chimera offered a solution that cured my plants from certain doom. He suggest that I get my medium back to a neutral state by doing the following:

1) Bi-pass the roots uptake of Mag with epsom salt foliar spray (underside of the leaves)
2) FLUSH my medium with water PH'ed at 8.0-8.5 until the runoff was stable at PH 7.0
3) FLUSH my medium with 150ppm Cal Mag (I use botanicare) and 200ppm feed (I use GH FloraNova Grow) for a solution of 350ppm and PH at 7.5 until the runoff was stable at PH 7.0

Now, I will add that each plant required approximateyl 4 hours in the bathtub. I had 3 of these to do so I spent roughly 12 hours all in all flushing these babies. Within a day I could see new growth resuming, it was green, not twisted and overall looking great.
My next watering I PH'ed at 6.8 and it came out.... 6.8

For a more in-depth look at what went on, there is 12 pages of "goodness" you are welcome to read over.

Cheers!

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ORIGINAL POST:


Hey all,

been a while since i've chimed in here. I'm currently on my 4th grow right now and I'm starting to lose faith in Pro Mix. I've done so much reading, asked so many people and I can't quite put my finger on the issue I'm having.

Here's what happened on my most recent grow:

Water: Tap water left out for 24 hours - 120ppm
Tap water PH: 7.1

Growing medium: Pro Mix - Seed starter with added perlite
Light: Kessil 150 + UFO LED
RM: 30%
Temps: 76-81 day / 70- 73 night.

The ladies are roughly 40 days into veg now, they are still tiny, have lost most of their leaves. I was gone for work for a month and a half so the lady did her best to take care of them but unfortunately over watered them twice which really took a toll.

Watering @ PH 6.2
Started adding Cal Mag @ 50ppm in week 3
Started adding GH Veg nutes @ 50ppm in week 3

These plants look like absolute garbage



Stems are deep purple, leaves are dying weekly, growth has almost completey stopped except for a bit of stretching. Really look horrible.

SO...

I popped a new seed this morning and put it in pro mix. But before doing that, I tried seeing what was going on in the medium.

Water going into promix = 7.1
Water runoff = 5.6

Woah.... Is this a problem? What is going on to cause it o drop so much?

So... I flushed the medium before putting the seed in so that it would at least read 6.0 in the runoff.

Now the kind folks at the THC store in Toronto have told me "Water at 6.5 in promix... Don't worry about the runoff." Online people say "Treat it like soiless and aim for 5.2-5.8"

I'm totally lost. Now here is where I am super confused. About a year ago, I had a couple of males in my mix. At maturity, I took them out of their grow boxes and put them on the window sill. Every few days, I gave them just enough water not to wilt, but definiteyl never had run off. What water did i give them? Straight up tap water @7.1. I've NEVER seen such green plants, growing healthy, quickly in my short growing career. These things were gaining almost an inch every other day. Stems were GREEN GREEN GREEN and everything look picture perfect.

Proof:

So what's up guys? What's going on? I need some guidance This whole experience has always given me a good harvest, but not beign able to get a good grow is very disheartening.

I'm guessing those veg nutes have a lot of NH4 in it... NH4 will drop your pH if you arent careful especially in pro mix peat, that is naturally acidic.... if i was you i'd back off the veg nutes for a little while and only use water... or some bloom nutes to gently raise your pH levels back to where you want them...
I'm not an advocate of testing run off for media pH readings.. but if thats all you got then run with it...

when you have you pH under control I'd feed with veg nutes once or twice a week only... or run with what has been successful for you in the past

Hey Bungle,

Definitely have been easing off of the nutes over the last 3 waterings cause the very tips have a bit of burn but are also showing deficiencies. The last 3 waterings have been 120ppm 6.2 going in and 320-400ppm 5.6 coming out.

That's the question really, is I'm not so sure I know the best PH range and if it's more important to nail the PH going in or coming out?

Add about 10-20% of worm castings to your promix medium. A bit extra regular compost would be good too.

If you have only ever given them 50ppm of veg nutes, they are severely hungry. Promix is a soilless medium, there is no food in it aside from some micros. Try giving them 500 or 700ppm of veg nutes, but half straight water first.

Kony, what about the Ph and my issue?

Kony is right, you underfed by a lot, since youre using promix as soilless I would ph water to 5.9 after doing around 600ppm of nutes. Thats really all you need to worry about. Feed as normal like this and flush weekly.

Cool. I'll give them a blast of food on their next watering and come back with updates.

Whoa why would you pH at 5.9??

Correct pH for promix is 6.5 - 6.8. The problem I see with these plants is that the pH was too low and the food was too low. Feed them at 600 ppm @ 6.5ph. Then plain ph'd water, then feed. Feed water feed water. Carefully ph'ing everything that goes in the pot to 6.5 - 6.8.

Kony and Lester nailed it. Severely underfed. pH your feed to c.6.5 and don't worry about run off pH. Good luck. -granger

Yikes.. I read 500 ppm the first time.. not 50.... my bad...I agree with the others

Hey lester, this is something ive been wondering about, I saw you have lots of exp. with this...

So I was under the impression pro mix can be used as a base mix for organic and when ammended you water @ 6.5 like any soil

Why is it when used as a hydro medium like this you still have to raise the ph?

50ppm! week 3!? they are starving dude. ph should be around 5.8 for hydro/soiless and around 6.5 for soil.

Thanks guys. Will report back.

Do the containers you're using have drainage? you might also be dealing with some root rot?

defininetly need more food. id give up on the promix tho and switch to coco, if ur running soilless i see no positives to running peat based mediums. u wont have to worry about overwatering, u get much better aeration in your pot which gives quicker growth, and larger yields typically. ph anywhere with 6.2-6.8 with the promix.

is promic much different that the old sunshine #4?
I grew for years with much success in sunshine 4, supported with dolomite lime, PH 6.3 veg, PH 5.8 - 6.0 flowering , 5.8 for the last 2 weeks. 3 week veg in 5 gal containers, hand water, 24 plants under 5000w , 2.5 to 4 oz per plant every time (NL#5 and original Shiskaberry)

not trying to question anyone experience as I am "just" getting back into the indoor thing so I'm curious, is the Promix different from sunshine 4 as far as PH requirements go?
bear with me, when I started growing my first plants in the early 90's the best plant foods for weed were Peters 20/20/20 and 10/52/10 hehehehe

Thats exactly why im wondering the same thing, sunshine 4 and 5.9 here

I'm using a knock off brand pro mix and loving it... Knock on wood the girls have been perfect this run... I have not checked ph once- I'm using the full heavy 16 line up and they claim, and I feel my girls are proof of it that with their "prime" product ph ing is unnecessary if your starting with a reasonable beginning point...

I also use fabric pits inside 5 gallon buckets I've drilled the living s out of... Seems to be working great giving the roots the air they want but the cloth bucket keeps soil from running out a rigid bucket with just holes while the rigid bucket gives me a firm base to attach LST tie downs... It's also broader than the commercial perforated rigid pots- so handy when your LSTing and going for a broad bushy lady..

I love the promix- first run I ever did was in straight perlite vermiculite in he pie bucket and it was a pain as they burned easy and had several deficiencies along way. In promix I'm able to give em full nutes and no burn or deficiency issues,.... I like the stuff....

Oh I Also throw a handful of melorganite in when mixing up and top dress it a time or two in veg with the stuff....

Don't give up

Redbuddz said:

Do the containers you're using have drainage? you might also be dealing with some root rot?

Click to expand...

Yes I do, cut out large holes at the bottom of the containers as well as poked some holes around an inch up from the bottom. The bottom half inch of the container is also straight perlite to help with drainage.