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Pro-Mix grow, soil pH on a few plants a bit high. Need some quick solutions to lower.

RSA

Member
Please, save me from spending 1-2 hours scouring hundreds of threads trying to piece together information to resolve this problem.

I have 20 plants under 2000w. The majority of these plants are fine, mostly healthy, etc. Some, about 5 total (with 1 that is very bad) are showing signs of what LOOKS to be nute burn but is probably lockout due to pH.

Tested soil ph with one of those 'mix water and soil together and add the pH powder' to the mixture, and judging by the resulting color my pH is very close to 7.

I obviously need to bring this down, but I am day 30 into my grow and don't want the plants to halt/hermie (as it may already do so), so what can I do (or add) to lower this back down to 5.8-6.5 range?

I have garden lime, but I'm not entirely sure if it's the right type, how much to use, how to specifically get pH down to 5.8-6.5, etc.

Urgent help would be greatly appreciated!
 

burns1n209

Member
Water with 3 times the volume of the pot with phd 5.8 water and that should help. Only thing to lower the ph is water the medium intill it flushs out. . So 3 gal pot.9gal of water I know thats a shit load but thats what it takes. Start with a gallon or 2 first and then go from there.
 

RSA

Member
Water with 3 times the volume of the pot with phd 5.8 water and that should help. Only thing to lower the ph is water the medium intill it flushs out. . So 3 gal pot.9gal of water I know thats a shit load but thats what it takes. Start with a gallon or 2 first and then go from there.

Jesus, for real?

That's 15 gallons for a 5 gallon pot...that's a lot of pH'ing and filling of water jugs..

I guess do that and upon the next watering feed like normal?
 
T

trichster

if you dont have a ppm pen get one ASAP. Check the inital runoff coming out of ones that look bad. give them ph balanced water with no nutrients until ppm runoff is steadily dropping every time you water.give them normal amount of water, 10% draining. id go until you hit 900ppm then evalute if they are ready for fertilizer . Just my guess though...
 

burns1n209

Member
Try to flush with just a 5 and see what happens to ph you may find that was enough water, then let dry and then feed as normal with 5.8
 

yesum

Well-known member
ICMag Donor
Veteran
Lime raises ph not lowers it. I use lemon juice mixed in with water and water using that. That is for water with a ph of 8 and test using drop test till it is around 6 or 6.5 ph.
 

Northernboy

New member
What was the ph of the water in the test. unless you put a lot of lime or organic amendments pro mix always run acidy .I feed at 6.3 and it's perfect it runs low in a month or two I add lime and adjust my feedinds to ph preference.if it really is high flush with 5.0 ten gallons .check run off next feed and repeat by adjusting again if needed.foil feed with kelp or seaweed till improves I've learned that promix alone is a pain amend with ewc 15 to 20 percent and a cup of dolomite per cf not a compressed cf either 7.5 gallons good luck bro peace and happy growing.
 
B

BasementGrower

if you dont have a ppm pen get one ASAP. Check the inital runoff coming out of ones that look bad. give them ph balanced water with no nutrients until ppm runoff is steadily dropping every time you water.give them normal amount of water, 10% draining. id go until you hit 900ppm then evalute if they are ready for fertilizer . Just my guess though...


this is another hydrostore bs meter lol.. i spend 145 on a ppm pen.. and i used it for about a week.. then realized.. unless u are trying to make ur own nute reginmen with nutes u may need it . but if ur using what they reccomend or less a lil more? shouldnt need a ppm pen.. ph pens are way more important.
 

RSA

Member
Here's the update.

Again, running 20 plants under 2k.

10 under each light.

All the same strain (white widow) except about 5 - a mix of blue satellite, kaya gold and blue mystic.

Strangely enough, the KG and BM are the ones showing issues, along with a couple widows.

I flushed them today, unfortunately due to time constraints I wasn't able to do the full 15 gallons, I did around 10-12 per pot.

Now after flushing, a lot of them look WORSE off...now I'm not sure if that's because there's a night and day difference between flushing with 12 gallons vs 15 gallons (3x pot volume) - but I looked online and many say to feed right after...which would make sense, but I'm afraid to feed already burned plants.

I tested the soil and the pH looks to be within range (yellow on the dye test, which indicates a pH close to 6 per the chart)
 

Rambro

Member
im no expert by any means, but i would flush em til the runoff ppms are really low, then wait a couple days and then hit them all with full strength ferts at the right ph.
 

RSA

Member
MaxiBloom

Basically, I started close to ~46 or so seeds, hoping for 20 females.

It was a mix from Nirvana's white widow to some freebies (blue mystic, kaya gold, blue satellite)

10 under each light. Both were only fed once or twice in veg, half-strength Maxi with some Protekt. Lush and green.

2-3 weeks into flowering, we're all good. I feed once, full dose of Maxi, one side looks fine (10 plants under 1 light) but the other side I'm noticing yellowing and a few other things.

I don't know where I went wrong, but I'm going to chalk this one up to the fact that you really can't predict with seeds whereas if you have a mother you know how she responds, you'll see uniformity across the grow room, etc. pH of the soil seems within range per soil tests, I always pH'd my water and nutes to what looked to be borderline 6 (i have yet to get a pH pen - it's on the list!)

there was one time where I added a full dose of Protekt, and I think that may *possibly* be why one side was 'worse off' than the other side, because I water on alternating patterns (IE water 10 on day 1, water the other 10 on day 3, the first 10 on day 5, etc)

I'm not sure if I see a benefit to using something like Protekt. It's selling point is that it's supposed to help the cell structure of the plants to protect it from 'environmental' stresses, but I'd have to see someone do an in-depth analysis of this before I use it again.

My NEXT grow will be straight pro-mix again, this time probably across the board nirvana white rhino. nirvana is cheap and won't cost me an arm and a leg to grab 40-60 seeds whereas when you buy 'better' genes to get the same quantity you're looking at hundreds upon hundreds of dollars.

I'd LOVE to be able to hold down a mother plant, and begin cloning. Problem is I've never ventured far enough to understand what would be needed to get something like that going.

I actually have a GrowLab GL145L with an old Homebox L where I have 4 haze freebies going at the moment (which are fine), and I think my best bet may be to setup the Homebox L with a smaller lighting system and simply maintain a mother plant.

I'm scared though, heh, because if I can barely keep some of my plants alive long enough to finish flowering, how the hell would I be able to keep a mother plant for months if not longer? I also know nothing about keeping a mother and cloning so I would be venturing off into another area when I have yet to perfect a grow all the way through without issues.

I started the seeds 1-1-2013. New years day. They all popped within 10 days, vegged for 4-5 weeks or so, and I can never find a definitive answer on when you start timing flowering (IE the flip to 12/12 or when you first start seeing bud sites form) so I have absolutely no idea how long I am along in flowering. I do know that I flipped to 12-12 late feb/early March, so they've had probably a solid 4-5 weeks minimum, 5-6 weeks max.
 
T

trichster

im no expert by any means, but i would flush em til the runoff ppms are really low, then wait a couple days and then hit them all with full strength ferts at the right ph.

Exactly!!! but not full strength ferts right away.
 
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