Making sense of my soil and water tests

[Lubdub]

I caught a deal on the river site for a pair of digital pens to measure EC and pH. 

 

Currently got a Banana Frost and a Watermelon Zkittles in the tent at 33 days into flower. 

The leaves on the plants are yellowing, going crisp and falling off. 

 

Hopefully these readings can shed some light.

 

Tap Water: PPM 149 / pH 8.45 / EC .6

 

Ban.Frost Soil: PPM 170 / pH 7.5 / EC .68

 

Wat.Zkittles Soil: PPM 167 / pH 7.5 / EC .7

 

SO im a bit lost. The soil is depleted, I've top dressed with some guanokalong complete organics, and upping my liquid feed for the next couple of feeds as the slow release stuff starts to work.

 

I also did a test batch of liquid nutrient feed (1ml fishmix, 3ml bloom) and tested the ppm at 700 and EC at 2.8.. So how do I get the ppm up but the EC down? 

 

numbers are hurting the brain..

 

 

 

 

 

[Lubdub]

think i might be calculating my EC wrong, the device shows 1400 for the EC in ppm μs. 

I did 1400 x 2 /1000 = 2.8 EC

 

But now I'm thinking its just 1400 / 10 = 1.4?

[Baron von greenback]

It's your pH mate it's way to high if I reading it right what pens have you got

Edited March 28, 2023 by Baron von greenback

[Lubdub]

Just now, Baron von greenback said:

It's your pH mate it's way to high if I reading it right what pens have you got

Yeh mate tap water pH here is really high. It seems the soil can handle it for the first month or so but eventually it gets out of whack.
As of a couple of waterings ago, I'm pHing what goes in the pots. The 'soil doesn't need pH' thing might hold up in the UK but not where I'm at.
edit. pens are cheap. 

Edited March 28, 2023 by Lubdub

[Baron von greenback]

Just now, Lubdub said:

Yeh mate tap water pH here is really high. It seems the soil can handle it for the first month or so but eventually it gets out of whack.
As of a couple of waterings ago, I'm pHing what goes in the pots. The 'soil doesn't need pH' thing might hold up in the UK but not where I'm at.
edit. pens are cheap. 

Ok mate I would pH everything from the start I also don't take notice of my ppms I just do everything to the EC I want 

[daggamon]

2 minutes ago, Baron von greenback said:

It's your pH mate it's way to high if I reading it right what pens have you got

Put u PH down to 6.5. Ppm early flower needs 800 to 1200. Depends what type of plants. Every one different. Even same batch of seeds. Do a lot of Google. And trial and error. 

[Lubdub]

Just now, Baron von greenback said:

Ok mate I would pH everything from the start I also don't take notice of my ppms I just do everything to the EC I want 

 

How are you calculating EC? My pen only gives readings in μs/cm.

[Baron von greenback]

Mines blue lab one it goes up in  0.2 increments I think

[catweazle1]

8 hours ago, Lubdub said:

 

How are you calculating EC? My pen only gives readings in μs/cm.

Divide by 1000... move the point 3 places to the left, 1000us is 1.0ec. Performing that operation, we have an EC of 1.0.

[Jon Smith]

@Lubdub Have the impression that measuring the soil/compost pH has many caveats compared to measuring evenly mixed liquids. For example, one should use distilled/ro water for the slurry so the water pH does not affect the measurements. Also most commercial composts are pH buffered with lime which dissolves slowly. In addition, have the impression that EC does not measure as expected with organic feeds compared to salt-based nutrients. Might be the same for soil/compost. For reference, local tap water has pH 8.4 and the local compost seems to buffer it fine.

[Lubdub]

2 hours ago, catweazle1 said:

Divide by 1000... move the point 3 places to the left, 1000us is 1.0ec. Performing that operation, we have an EC of 1.0.

 

thanks mate, it was late last night when i realised through the power of deduction that my calculations were wrong haha... thanks for the confirmations 

 

44 minutes ago, Jon Smith said:

@Lubdub Have the impression that measuring the soil/compost pH has many caveats compared to measuring evenly mixed liquids. For example, one should use distilled/ro water for the slurry so the water pH does not affect the measurements. Also most commercial composts are pH buffered with lime which dissolves slowly. In addition, have the impression that EC does not measure as expected with organic feeds compared to salt-based nutrients. Might be the same for soil/compost. For reference, local tap water has pH 8.4 and the local compost seems to buffer it fine.

 

I have used RO water to measure my soil mate Been a week in the making waiting for the pens to arrive, so did some fair reading leading up to that point. Soils were slurred with RO water for around 14 hours, then drained through cheese cloth. The remaining compost tea is what I tested. 

 

Perhaps my soil is not as organically rich as yours, their last pot up was in Biobizz Lightmix as that's all I had on hand, that was about a month ago.

All in all seems like I'm severely under feeding and with that the soil in the pots have a slightly high pH of 7.5 - a few watering at the correct pH should bring it back down to the optimal window, i hope.
 

[Military Grade]

Ever thought you might be doing too much to a soil grow?

 

Most of use don't use EC pens or PH meters when growing in soil.

[Slippy One]

You've got all the gear go full coco next round, ditch the biobizz gunk. Try Growers Ark, they do a hard or soft version and will also test your tap water for £30. Remember the golden 3:1 cal mag ratio is crucial. My tap water was 19:1 so I add mg only. You can also use your local water report which should be available online

[Military Grade]

£32 now

[KC]

I don't think Ec readers work with organic nutes.