Nov 23, 2019

Simple Watering Question

On my second grow, and so far everything is looking good. Not wanting to make any mistakes, I have a small question about watering.

My PH is at 6.2 to 6.3 in the jug. However, testing the runoff it's 5.5 to 5.7. Do I want to increase the PH in the jug (before watering), so the runoff PH is Higher (6.2-6.4)?

mwhite9829

Nov 23, 2019

Im happy when I see a 1-1.5 drop in run off. Wouldn't be worried about that.

Mr. Grow It

Nov 23, 2019

Yes, that's exactly what you want to do.

toasterr

Nov 25, 2019

Thanks. Had to raise the to 7.2(in the jug) to get a ph to 6.1 in the runoff. Is 6.1 to low in the runoff?

Mr. Grow It

Nov 25, 2019

@toasterr

That should be ok for soil. Then over the next few waterings, as you're giving a higher pH, the runoff pH will drift up. It seems like most growers consider 6.5 pH the sweet spot.

toasterr

Nov 27, 2019

@Mr. Grow It

. Thanks, made the adjustments today. Runoff is now 6.4 - 6.6

D K

Nov 26, 2019Edited: Nov 26, 2019

Runoff ppm is coming mostly from the collection of salts at the bottom of your pot. The best way to check soil ppm is to do a slurry test. Simply take one part soil from the edge of the pot about 1-2" down and mix it with one part ph neutral water like distilled water and wait about 5 minutes, then test ppm and pH for a more accurate reading.

Mr. Grow It

Nov 26, 2019

@DK can you link me to the source for where you read that the runoff PPM is mostly salts? This is the first time I've ever heard that so I'd love to learn more about it.

D K

Nov 26, 2019

@Mr. Grow It

Don't really have a "source" just a collection of research, videos and my own experience. Try a slurry when you get a chance, and you'll see the difference. The bottom of the pot is a collection of numerous feedings that push down unused or unabsorbed nutrients into the lower strata of the soil where it can build up until it is pushed out of the bottom with an excessive flush. The plants absorb the majority of their nutrition and needs from the upper strata of the soil level, which is why a slurry will show much lower ppm's than taking run-off.

Mr. Grow It

Nov 26, 2019

@D K

Got it. I have heard of the slurry test but haven't tried it; I did hear is it more accurate but I also heard the difference between runoff vs slurry is miniscule. I'll have to do some more research and give it a try. Any major differences when talking about runoff vs slurry for soil vs coco coir?

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