Runoff - ph and ppm help please

[overmyhead]

Alright, so for the first time in the new pots I soaked one of the plants all the way through (the others still have moisture on the outside edges and I want them to shoot roots out to find it. I watered it with phd (6.5), filtered water with a tiny bit of cal mag and some micro root stimulants. THe ppm was 150.

SO I decided to pull some runoff and test it since I now have a ph pen. Well, I am a little bit freaked out about the results and doubtful as to their accuracy. The ph registered 5.7 and the PPM topped out my Truncheon - it just flashed at the top level (1800.)

Two things make me question the results - since this is runoff from a peat based product, wouldnt you expect the ph to be high because it is going to cotain billions of tiny peat particles and same with the ppm - dont all those tiny pieces of peat go into the equation? So can you ever really get an accurate runoff measurement?

Here is a pic of the runoff jsut so you see what I mean.

 

[overmyhead]

so, i think i found the answer to the ph issue - i need to seperate some of the soil, run neutral water through it and test that runoff. But, arent the tds still going to be off because of all the peat particles in the runoff???

 

[KaliKitsune]

You don't need to worry about PPM in soil. Just watch your pH and adjust it as necessary.

PPM/TDS/EC is for hydroponics mostly.

 

[MEANGREEN69]

You don't need to worry about PPM in soil. Just watch your pH and adjust it as necessary.

PPM/TDS/EC is for hydroponics mostly.

WHAT UR WRONG ON THAT ONE BRO!!!.. i think u had some salt build up in ur coco,so when u watered it came out and ur runoff's PH/PPM jummp...just like when u add nutes to water ur ph will drop and ppm goes up..ya dig....i think coco/peat has a ph of 6.5/7..and has a electeric charge/ec which whould let it hold salt...do a flush with ph'ed water tell it's the same as the water thats going in....good luck and peace..MEANGREEN

 

[KaliKitsune]

WHAT UR WRONG ON THAT ONE BRO!!!.. i think u had some salt build up in ur coco,so when u watered it came out and ur runoff's PH/PPM jummp...just like when u add nutes to water ur ph will drop and ppm goes up..ya dig....i think coco/peat has a ph of 6.5/7..and has a electeric charge/ec which whould let it hold salt...do a flush with ph'ed water tell it's the same as the water thats going in....good luck and peace..MEANGREEN

Hahaha.

No disrespect but I substitute-taught for a high school Horticultural Science class.

Your first problem is you're using peat. Peat is antibacterial, and your urea-based nitrogen nutes won't get absorbed because of the lack of bacteria to convert into nitrate form. Switch to sphagnum moss and you won't have that issue, and your salt levels will drop.

Next - peat moss and most types of moss act like a sponge. This will cause drastic pH changes as it gets dry. If you keep nutes and water circulating, you'll be better off. Aerated water will maintain a lower pH, and will allow for better tolerance of higher nutrient levels.

Testing runoff for potential hydrogen is wildly inaccurate in a moss-based system, and using a PPM meter is pointless in most any moss system because you have no clue how much of that PPM is particulate matter from the growing medium. Hydroton suffers the same issue until you rinse it off a few times, mosses have this problem constantly.

Giving a teacher a dunce cap, how quaint.

 

[overmyhead]

Thanks for the input. I had feeling that any kind of runoff test was going to be off.

I just transplanted so the majority of the soil is brand new and only has the initial "nutrient charge" in it. I have seen amazing plants and yields come out of this same soil mix - I just never had a place to grow so I didnt pay attention to a lot of the details, I have used a lot less ferts than they did but the same brand, and am using 6.5 water just like they did. I am pretty sure that the mix will sustain beneficial bacteria - as a matter of fact it has some in it.

Bacillus subtilis MBI600 was tested in the peat based substrate PRO-MIX® BX as a biocontrol agent against root rot and damping-off caused by Pythium spp. and Rhizoctonia spp. The assays were conducted on two vegetables (tomatoes and sweet peppers) and two ornamental plants (cockscomb and garden balsam). Data obtained in this study demonstrated the beneficial effect of the presence of B. subtilis in PRO-MIX® BX. Damping-off and root rot were significantly reduced and root growth was significantly improved, resulting in healthier plants. Data from this study were used to support registration of PRO-MIX® BX with B. subtilis as a biofungicide in the marketplace to reduce root rot disease.

 

[MEANGREEN69]

Hahaha.

No disrespect but I substitute-taught for a high school Horticultural Science class.

Your first problem is you're using peat. Peat is antibacterial, and your urea-based nitrogen nutes won't get absorbed because of the lack of bacteria to convert into nitrate form. Switch to sphagnum moss and you won't have that issue, and your salt levels will drop.

Next - peat moss and most types of moss act like a sponge. This will cause drastic pH changes as it gets dry. If you keep nutes and water circulating, you'll be better off. Aerated water will maintain a lower pH, and will allow for better tolerance of higher nutrient levels.

Testing runoff for potential hydrogen is wildly inaccurate in a moss-based system, and using a PPM meter is pointless in most any moss system because you have no clue how much of that PPM is particulate matter from the growing medium. Hydroton suffers the same issue until you rinse it off a few times, mosses have this problem constantly.

Giving a teacher a dunce cap, how quaint.

ok..teacher...well i test the PH& PPM of all my palnts that are in coco,why cant he just test the runoff of water of the moss,to see whats the ppm....then add nutes and SUBtract the ppm of the 1st waters runoff?? and if u substitute-taught at a high school Horticultural Science class,all that means is u didnt study much of any one subject and u work where u can. be it meth,science,PE..ect..so the dunce cap stays..i'd rather study the indoor grow bible then take tips from a substitute teacher

 

[overmyhead]

good idea mean green.

 

[MEANGREEN69]

well thanks ph & ppm where my hardest prob at 1st..im just now getting a grip on them. they are great tools when growing this pant we all love.good luck,grow safe,peace..MEANGREEN..

 

[KaliKitsune]

ok..teacher...well i test the PH& PPM of all my palnts that are in coco,why cant he just test the runoff of water of the moss,to see whats the ppm....then add nutes and SUBtract the ppm of the 1st waters runoff?? and if u substitute-taught at a high school Horticultural Science class,all that means is u didnt study much of any one subject and u work where u can. be it meth,science,PE..ect..so the dunce cap stays..i'd rather study the indoor grow bible then take tips from a substitute teacher

He can't because the rate of decay of organic matter varies. It would NEVER, EVER, *EVER* be a consistent reading. Coco is far tougher than moss, so it rarely affects the PPM of any hydro solution, because it doesn't decay nearly as much.

Testing runoff is too inaccurate as well, as moss and coco aren't full of stabilizing buffers like soil, you won't get an accurate reading of what's going on, just a vague idea. A direct probe into the medium is the best way to go.

 

[overmyhead]

He can't because the rate of decay of organic matter varies. It would NEVER, EVER, *EVER* be a consistent reading. Coco is far tougher than moss, so it rarely affects the PPM of any hydro solution, because it doesn't decay nearly as much.

Testing runoff is too inaccurate as well, as moss and coco aren't full of stabilizing buffers like soil, you won't get an accurate reading of what's going on, just a vague idea. A direct probe into the medium is the best way to go.

That makes sense too (my heads spinning) what kind (brand) probe would you recommend? Thanks.

 

[KaliKitsune]

Most meters and probes will do the job just fine, just remember to buy the vials of buffer solution and calibration solution for the pH probe, and when you're done using the pH probe make sure to clean it and store the probe in the neutral buffer solution.

 

[overmyhead]

Most meters and probes will do the job just fine, just remember to buy the vials of buffer solution and calibration solution for the pH probe, and when you're done using the pH probe make sure to clean it and store the probe in the neutral buffer solution.

I meant to probe the soil as you suggest - I have one (cheapo three in one) but it requires you to mix the soil with an equal amount of water to test - i can't see how that would give you a tru reading. THanks again.