First grow, ph questions

[bearhair]

Hi guys and gals, working on my 1st grow and I have some questions about runoff ph. Growing in ffof soil and using ff nutrients. Started out using ro water and switched to rain water because of the expense. Regardless I noticed the issue before the switch. I'm using a bluelabs combo meter and I calibrate every 30 days.. so I allways ph to 6.8 before feeding or watering and the runoff is all ways between 5.5 and 6.1... 6.1 is ok but 5.5 Is not... Is this a common issue with ffof, do I need add lime. Nearing the end of the grow and yield is going to light.. Thanks in advance.. any in site would be appreciated...

 

[Big Sul]

NoNeed to water til runoff in soil, that’s a coco thing. And I believe that adjust to 6.4’ish AFTER adding nutes. Check what I’m saying, but this is my understanding. I’m a “water only” guy, and I still ph my water to 6.4.

 

[bearhair]

Nearing the end of the grow and yield is going to be lite

 

[bearhair]

NoNeed to water til runoff in soil, that’s a coco thing. And I believe that adjust to 6.4’ish AFTER adding nutes. Check what I’m saying, but this is my understanding. I’m a “water only” guy, and I still ph my water to 6.4.

Thanks for the reply.. but I think my root ph is way too low. I could be wrong. I'm growing in soil.. I just don't know

 

[Big Sul]

I’d be interested in what your water ph is AFTER you add nutes to the water

 

[DCLXVI]

@Big Sul is correct. Add everything to your water, then pH to the right number.

 

[olbobcat]

You should know what the ppms in and out are as well. If the Ph is going down PPMs could be going up as well. I do slurry test 1 oz soil 1 oz water then see where your ph is and your ppms. If your ppms are high and getting higher you need to use some phd water till you get it back to lower level. If your soil ph is low add water at a higher ph level for a few feeds. The problem using RO or rainwater is that it lacks Calcium or buffering. It can be a lot more touchy. I could have 5 plants growing and feeding them all the same and one will look a little off and sure enough a soil ph problem.

 

[Bruce Campbell]

Thanks for the reply.. but I think my root ph is way too low. I could be wrong. I'm growing in soil.. I just don't know

When you fertilize, your run-off pH is not your soil pH. Your run-off pH is your fertilizer pH plus/minus what you washed out of the soil and what was ad/absorbed by the soil.

To measure your soil pH, you typically use either the pour-thru method or the slurry (SME) method. They can give slightly different results, but the pour-thru method is a bit easier and more common. Here's a thread describing it:

https://www.autoflower.org/threads/...-for-run-off-testing-and-ph-estimation.41733/

 

[Mañ'O'Green]

Run-off is a poor measure of anything. It can show trends but IMPO is worthless. You should be fertigating/watering at 6.4 PH.

 

[bearhair]

@Mañ'O'Green, I'll have to back and read your nutrient blog again. Could have sworn it said 6.8.. any way, thanks for the reply..