In and out ph readings

I noticed that on some of my runoff ph readings are 5.5 and I am putting in 6.5. Growing in soil but two of three plants have low ph levels. Any thoughts, advice from the more experienced growers welcome. All plants are looking great just wondering why.

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It depends on the age of the plant and the substrate you are using. If in mid to late flower I would expect that as the plant consumes itself and some root mass dies and acidifies the soil.

If in veg then I would suggest top dressing the soil with a layer of dolomite lime which will bring it up and buffer it to the correct range.


Thanks , that makes sense cause they are in late flower.

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I pretty much figured that. You can let it ride; you may even see some interesting colors if it drops down in the low 4’s.

Colors ? explain please.

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Some cultivars develop anthrocyanins (blues) as a response to acidic soil or low temperatures. Some don’t.