Input pH vs. Soil pH vs. Runoff pH

I'm growing in soil with a high perlite content(30-40%) and I have noticed some discrepancies in my input pH(water/nutes), compared to my soil pH(tested with cheap soil meter https://amzn.to/2N8TYMv) compared to my runoff pH.

My input water pH is right around 7 with ppm of around 330. When I feed, the pH is adjusted to 6.4pH with ppm around 1800(currently in flower). My runoff is coming out with a pH around 5 and a ppm of around 1300. When I test my soil with the cheap soil tester, if falls around a pH of 7-8(not very accurate). I'm concerned about my runoff pH numbers compared to the soil tester. I have read that runoff pH is not always the best measure of soil pH, but I'm not sure if I can trust my soil pH tester which says I'm in a good range.

Overall my plant looks relatively healthy, except for it being a little lighter green which could be a nutrient lockout.

So I guess my question is, how important/accurate is the pH runoff test? Should I adjust my input water/nutes Ph above 7(7.5) to try and bring the pH of the runoff up to a safer range? I'm confused how my runoff pH is so low when my input pH is always in a safe range. Should I trust my soil tester for pH or my runoff? With all of that said, this plant is 1 week into flowering so I don't really want to flush unless I absolutely have to. I would rather try and bring the runoff pH up slowly by adjusting my water/nute pH in future watering/feedings.

Please advise and thank you.

1800 PPM for a plant that size is mental. That works out at an EC of 3.6-3.7. How is that not dead?

You sure this is right,?

Sounds like lock out due to high concentrations of salt build up.

Silentvirtue said:

1800 PPM for a plant that size is mental. That works out at an EC of 3.6-3.7. How is that not dead?

You sure this is right,?

Sounds like lock out due to high concentrations of salt build up.

Click to expand...

Not to mention his plant that is "currently in flower" isnt even showing sex!

However before I get distracted. I dont measure run off at all. I feed my coco at 5.5 and noticed the same problem pH was always more towards 6. Wasted fuck loads of money in nutes and pH gear trying before I gave up. Thats how I do it now.

I'd only measure it for reference really.

I have an interesting question now tho. Running very high perlite contents in soil medium grows does this then constitute to apply hydro basic principles. Also at what sort of percentages. As this would surely affect availability due to PH.

I was thinking based on drainage and airation along side the ability for soil to become saturated greatly impacted.

Silentvirtue said:

However before I get distracted. I dont measure run off at all. I feed my coco at 5.5 and noticed the same problem pH was always more towards 6. Wasted fuck loads of money in nutes and pH gear trying before I gave up. Thats how I do it now.

I'd only measure it for reference really.

I have an interesting question now tho. Running very high perlite contents in soil medium grows does this then constitute to apply hydro basic principles. Also at what sort of percentages. As this would surely affect availability due to PH.

I was thinking based on drainage and airation along side the ability for soil to become saturated greatly impacted.

Click to expand...

The more you water down soil with perlite/coco/rainbows/unicorn farts, the more it is like growing in hydro because thats essentially the environment you are creating whether thats the goal or not. A plant with an adequately sized pot of good soil can get to harvest without adding any additional amendments. Cut the pot size down, fluff your dirt with perlite, expect to need to FEED.

It had pre-flowers before I switched the light. 100%

The light was flipped last Saturday. Its only been 5 days in flower.

JoeBlow5823 said:

Not to mention his plant that is "currently in flower" isnt even showing sex!

Click to expand...

joedirt420 said:

It had pre-flowers before I switched the light. 100%

The light was flipped last Saturday. Its only been 5 days in flower.

Click to expand...

My bad, i dont see sex in the pic. Not the point. Your not in flower until you see flowers. The plant is still 95% focused on strong veg growth, not flower.

I'm using Fox Farms nutes, and 1800 ppm for this stage is in the range they recommend.

With regards to the perlite I was wondering the same. A high % of perlite would allow the roots to breath better and make it easier to prevent salt build up(This was my thought anyway). This is the first time I have tried doing it this way.

Silentvirtue said:

1800 PPM for a plant that size is mental. That works out at an EC of 3.6-3.7. How is that not dead?

You sure this is right,?

Sounds like lock out due to high concentrations of salt build up.

Click to expand...

When I said in flower, I meant that I had switched my lights. Apologies for the confusion.

JoeBlow5823 said:

My bad, i dont see sex in the pic. Not the point. Your not in flower until you see flowers. The plant is still 95% focused on strong veg growth, not flower.

Click to expand...

joedirt420 said:

I'm using Fox Farms nutes, and 1800 ppm for this stage is in the range they recommend.

With regards to the perlite I was wondering the same. A high % of perlite would allow the roots to breath better and make it easier to prevent salt build up(This was my thought anyway). This is the first time I have tried doing it this way.

Click to expand...

Those numbers are out of control.

joedirt420 said:

I'm using Fox Farms nutes, and 1800 ppm for this stage is in the range they recommend.

With regards to the perlite I was wondering the same. A high % of perlite would allow the roots to breath better and make it easier to prevent salt build up(This was my thought anyway). This is the first time I have tried doing it this way.

Click to expand...

Another grower having issues with Fox Farms while following that feeding chart. I've commented twice in the last couple days about it. I'd cut the feed strength down significantly. I could care less what FF's feed chart says. That's too much fertilizer.

JoeBlow5823 said:

Those numbers are out of control.

Click to expand...

Which is why so many people have issues when following that feeding chart. 1800 ppm. I never go much higher than half that anytime during the grow. I also never have a single nutrient related issue either. Overfeeding is responsible for the majority of issues many people have.

xtsho said:

Another grower having issues with Fox Farms while following that feeding chart. I've commented twice in the last couple days about it.



Which is why so many people have issues when following that feeding chart. 1800 ppm. I never go much higher than half that anytime during the grow. I also never have a single nutrient related issue either. Overfeeding is responsible for the majority of issues many people have.

Click to expand...

Yup. They encourage people to fuck up their grow so they think they need to go buy more shit.

Thank you. Good to know.


I literally just fed this plant today, should I flush it out right now? Or should I wait to see how it responds?

I was more worried about flushing it a week into flowering, but now you have me worried I'm going to burn the hell out of it.

xtsho said:

Another grower having issues with Fox Farms while following that feeding chart. I've commented twice in the last couple days about it. I'd cut the feed strength down significantly. I could care less what FF's feed chart says. That's too much fertilizer.



Which is why so many people have issues when following that feeding chart. 1800 ppm. I never go much higher than half that anytime during the grow. I also never have a single nutrient related issue either. Overfeeding is responsible for the majority of issues many people have.

Click to expand...

joedirt420 said:

Thank you. Good to know.


I literally just fed this plant today, should I flush it out right now? Or should I wait to see how it responds?

I was more worried about flushing it a week into flowering, but now you have me worried I'm going to burn the hell out of it.

Click to expand...

I would reduce feeding to like 700 ppm. Im an organic grower so im not the best guy to ask exactly what to do. Are you growing in coco or soil or ?

joedirt420 said:

Thank you. Good to know.


I literally just fed this plant today, should I flush it out right now? Or should I wait to see how it responds?

I was more worried about flushing it a week into flowering, but now you have me worried I'm going to burn the hell out of it.

Click to expand...

Well according to their feeding schedule instructions should plants show signs of stress or color irregularities you're supposed to use more of their products to flush the unwanted salts out. So they have a solution for having people overfeed their plants. They also have people flushing every 3 weeks with one of their products once you start flowering. Why don't they just have people feed less so there isn't massive salt buildups screwing up peoples grows?

The more I look at the feeding schedule and all those bottles of products the more disgusted I get. I'll use their soil FFOF and Happy Frog but I'd never use their nutrients. If I had to I would just use the trio at reduced strength. Are you using everything on that chart?

xtsho said:

Well according to their feeding schedule instructions should plants show signs of stress or color irregularities you're supposed to use more of their products to flush the unwanted salts out. So they have a solution for having people overfeed their plants. They also have people flushing every 3 weeks with one of their products once you start flowering. Why don't they just have people feed less so there isn't massive salt buildups screwing up peoples grows?

The more I look at the feeding schedule and all those bottles of products the more disgusted I get. I'll use their soil FFOF and Happy Frog but I'd never use their nutrients. If I had to I would just use the trio at reduced strength. Are you using everything on that chart?

Click to expand...

I'm only using the three basic liquid nutes(Grow Big, Big Bloom, Tiger Bloom), and the three granular nutes(Open Sesame, Cha Ching, and Beastie Bloomz).

I only give nutes every other watering. I'm going to see how the plant responds and go from there, if it looks like its burning, i will flush it out and start using fewer nutes. I know my pH in is good for both water and nutes, but I'm guessing my ppm is too high in the nutes and that is affecting the runoff.

I did a slurry test last night and the pH came in at around 6 so maybe the runoff is not that important, and I'm overthinking it.


Thanks for all the advice. I'll keep you all posted.

joedirt420 said:

I'm only using the three basic liquid nutes(Grow Big, Big Bloom, Tiger Bloom), and the three granular nutes(Open Sesame, Cha Ching, and Beastie Bloomz).

I only give nutes every other watering. I'm going to see how the plant responds and go from there, if it looks like its burning, i will flush it out and start using fewer nutes. I know my pH in is good for both water and nutes, but I'm guessing my ppm is too high in the nutes and that is affecting the runoff.

I did a slurry test last night and the pH came in at around 6 so maybe the runoff is not that important, and I'm overthinking it.


Thanks for all the advice. I'll keep you all posted.

Click to expand...

see bold above, that is part of your problem, the other is way to many nutes that contain high phosphorous. note the middle number of all 3 of those joke additives. I use very little P throughout the whole grow.I would NEVER use any of those plant killers.

.

OPEN SESAME® SOLUBLE FERTILIZER
For Early Flowering Stage
5 - 45 - 19
Open Sesame® is a high-phosphorus soluble fertilizer that’s designed for use during the early weeks of flowering to support vigorous blooming and bud development.

CHA CHING® SOLUBLE FERTILIZER
For Late Flowering Through Harvest
9 - 50 - 10
BEASTIE BLOOMZ® SOLUBLE FERTILIZER
For Mid-Flowering Stage
0 - 50 - 30
Beastie Bloomz® is a high-phosphorus soluble fertilizer specially formulated to support blossom development during mid to late flowering. For use in soilless mixes, soils, hydroponics, and aeroponic systems

Hey man looks like she is coming along, its still so early in flower you can get things back on track.

I noticed a few things that you could consider.
first don't use cheapo soil probes they are junk.

1800 ppm seems very high even at the peak of flower that is alot. I would search around a bit to see if anyone else is feeding those nutrients at that ppm range successfully.

teddy has a point that all of those bloom nutrients are very high in phosphorus and given all together are likely causing a toxicity. excess phosphorus will lock up zinc and magnesium. The striping in the leaves and the yellowing in the newgrowth + stunted twisted thin leaves hints towards this. Id drop the extra bloom nutes for now and just go with the base nutrients.

She isnt straight burning so thats good. Take a new picture and closely monitor how much she grows over the next week. It should be stretching but may be stunted. personally I don't go over 1200-1300 with my biggest hungriest girls

your picture looks to be in hps lighting so I don't want to make comments because I cant see the true colors, take pics with lights off next time to be more detailed

What EC were you feeding in veg and how did they look?

That makes sense.

I'm going to stop over thinking and just watch my plant and see how it behaves. I have grown with these same nutes two other times(2007 and 2013) and they mostly turned out fine. Its been awhile so I keep second guessing myself.

There is so much conflicting info. Some people say, follow the instructions your nutes give you, others say thats totally wrong and cut it back.

I think I'm going to switch brands when these nutes are gone.

Thanks for the advice.

kingkush4200 said:

Hey man looks like she is coming along, its still so early in flower you can get things back on track.

I noticed a few things that you could consider.
first don't use cheapo soil probes they are junk.

1800 ppm seems very high even at the peak of flower that is alot. I would search around a bit to see if anyone else is feeding those nutrients at that ppm range successfully.

teddy has a point that all of those bloom nutrients are very high in phosphorus and given all together are likely causing a toxicity. excess phosphorus will lock up zinc and magnesium. The striping in the leaves and the yellowing in the newgrowth + stunted twisted thin leaves hints towards this. Id drop the extra bloom nutes for now and just go with the base nutrients.

She isnt straight burning so thats good. Take a new picture and closely monitor how much she grows over the next week. It should be stretching but may be stunted. personally I don't go over 1200-1300 with my biggest hungriest girls

your picture looks to be in hps lighting so I don't want to make comments because I cant see the true colors, take pics with lights off next time to be more detailed

What EC were you feeding in veg and how did they look?

Click to expand...

I only have a pH and ppm meter so I don't know the EC.

I was hesitant to trust the probe, but I did a slurry test last night and the pH came in around 6 so maybe its not that bad.

I think I will drop the extra bloom nutes as you suggest. But keep in mind you only use one of the bloom nutes for feeding at different stages. You are not using all three of those bloom nutes at once.

For example I just fed it yesterday and it received the Big Bloom, Grow Big, Tiger Bloom and 1/4 tsp of the Open Sesame. And some of the 1800 PPM was me using pH up to get the pH a little higher.

My pH was closer to 6 on my nute mix with a PPM of around 1500, but I was worried about my pH being too low so I used pH up to get it to around 6.5 which moved my PPM up to 1800. The new growth does look a little bit twister, so maybe this is related to too much P.

Thanks for all the advice.

Next watering will just be water and molasses, and I will adjust it to a safe pH, and give it a good drink(mini flush) just to be safe.