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)?
Im happy when I see a 1-1.5 drop in run off. Wouldn't be worried about that.
Yes, that's exactly what you want to do.
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?
@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.
@Mr. Grow It . Thanks, made the adjustments today. Runoff is now 6.4 - 6.6
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.
@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.
@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.
@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?