Question about runoff pH inconsistency

[marx2k]

2 weeks ago, I was watering my plants (sitting in Pro-Mix with a small amount of gardening lime) using Flora Nova Grow, CalMag and Old Age Kelp.

The nutes going in were pH 5.7, the runoff was 6.8. PERFECT.

Now the last 2 times I watered, the pH going in was 5.7, but the runoff was 6.3.

What could have changed?

 

[greenisgold]

Your soil make up has changed due to the salts building up, your soil breaking down and the lime which takes time to take effect. This is normal and is the reason why we have ph pens. Just add some ph up to your water and your good to go, but I always adjust my soil to 6.3.
Peace

 

[marx2k]

Yeah, but this is soilless. Though I'm not sure how much that matters. This is mostly peat and perlite. Do you think I should flush for one feeding? I was adding pH to my wayter to bring it to 5.7/5.8 - I guess I should bring it to about 6.1/6.2

 

[greenisgold]

Since it's soilless/promix-duh should have read your post better, you will want the ph level to be from 5.6-6.2. Adjust nutes going in at around 5.8-6 and all should be fine. 6.8 is way to high for soiless, and I do not think you should have added any lime.
Any promix-pros?

 

[PhillyPride]

I currently use Pro -Mix HP with no additives your ratios are fine and Greenisgold pretty much hit the nail on the head 6.8 is way to high for Pro-mix, it takes one or two feedings after transplanting for PH to regulate unless you use a ton of water during the initial feedings. You want your run off 6-6.5

 

[Rufid]

I tried to get this answere before,this helps alot.thanks guy's.

 

[marx2k]

Yep thanks for the advice. Though they seem perfectly healthy with 6.8 runoff, and have been growing out of control... I will scale it back to about 6.3 from now on for the pro-mix.

So can someone explain why pro-mix needs to have lower pH than soil? Don't roots uptake nutes at the same range in pro-mix as well as soil?

 

[Blackvelvet]

Since it's soilless/promix-duh should have read your post better, you will want the ph level to be from 5.6-6.2. Adjust nutes going in at around 5.8-6 and all should be fine. 6.8 is way to high for soiless, and I do not think you should have added any lime.

Great answer