Runoff PPMs in a Soil Grow -- Check out these numbers

Beginner Autoflower Suport
#1

Hey @MDBuds, long time. Hope your Memorial Day Weekend has been wonderful. I have a dilemma for you. We’ve talked a lot about runoff and ppms in soil, and you’ve told me ppms will make me crazy. And, they are. But – can you help me with this situation?

White Widow auto. End of 11 weeks from seed in ground. Soil FFHF + FFOF + Pearlite. Indoor grow. Temps 80 degrees, 45% RH. Light 800 - 1000 PAR. All in flower, several already flushed for harvest over the next week or two. Others may take three weeks or so. All plants look healthy and happy.

Two questions:

  1. Do I need to flush out the non-flushed plants because ppm is so high? They are about three weeks (or more) from harvest.
  2. What should I learn from this data?

Non flushed plants got:
Flowertime Nutes and CalMag at 6.4 pH and 30 ppms going in.

The numbers:

Not yet flushed plants – some really high ppm #s. pHed water in at 6.4 and 30 ppms.
Plant #, Water out/ppms out
#7 6.1/3800 ppm
#8 6.2/2800
#4 6.4/2300
#2 6.2/2845
#5 6.3/3200

Flushed plants – all under 2000 ppms. Water out/ppms out
#10 6.2/1300
#6 6.3/1976
#9 6.2/1850

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#2

@GrnyGrows what measurement is your meter using? Is it us/cm or s/cm?

#3

I have us/cm and ppm – I’ve been using ppm. It’s an economy meter – ie cheap one.

#4

@GrnyGrows sorry it’s been so long. Got caught up in life. As far as your runoff ppms they are of no concern in a soil grow unless you are using an inert medium or sterile neutral soil. The FFOF and FFHF you used will have extremely high runoff ppms even without feeding. So keep that in mind for the future. If you want to dial things in with salt nutes and do a hand fed hydro or hybrid system and monitor those things using some good coco, peat, or inert soil would be best.

All of your phs look good though and you’re good for flush. Should be a good harvest for you. Happy growing.

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#5

I’ve missed you. Thanks a million. I understand about life getting in the way. :upside_down_face:

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#6

Quick question on another subject. Can I use HGCC Organic Nutrients line (not Standard) in FFHF+FFOH? I have a full package of the nutes and would like to use them.

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#7

@GrnyGrows yes you can. It would work better with organics as well. I’ve used them with soil and handfed coco hydro so far and they’ve worked pretty good.

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