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Growing Organic Cannabis - How do I manage pH?

Question: How Do You Manage pH with Organic Soil? 

How do I manage the pH of my soil when growing organically?

Young marijuana plant is loving lifeMore info: I've heard that many pH control kits can kill beneficial bacteria in the soil.

I was watering my cannabis plants tonight, and I mixed in a half strength dose of bloom nutes. So I test the PH and it is right in range, about 6.5. When I tested the runoff, it was really acidic at around 5.5.

What am I doing wrong, and how do I correct pH in my organic soil without hurting the micro-organisms the help the roots?


1.) Usually You Don't Need to Worry About pH When Growing Cannabis With Organic Soil

When growing cannabis in organic soil, you usually don't need to adjust pH, but if you do you want to use natural sources of PH Up and PH DownWhen growing cannabis in organic soil, some of the most important things happen before you even germinate your plants. The more effort you put into starting with great organic super soil, the less you'll have to worry about during the actual grow itself. If you've set things up properly, you probably don't even need to think about pH.

When growing marijuana organically in a super soil environment, there are tiny organisms in the soil that break down nutrients and "feed" them directly to your roots. When you enlist the microorganisms to do the work of making nutrients available to the roots, pH management becomes much less important! When growing organically, you also depend on your soil and the humates it contains to automatically buffer the pH. If you start with the right soil, you usually don't have to worry about pH at all!

Learn how to make organic super soil (custom-formulated soil for cannabis plants - for those who want to do organic growing the "real" way, without having to worry about pH or giving nutrients)

Unless you are noticing actual symptoms of nutrient lockout (nutrient deficiencies) than pH adjustment is probably not necessary. Only try to adjust the pH if you notice actual pH nutrient problems in your plants.

In general with organic growing, it's recommended you do not adjust or try to manage pH until you know something is wrong. In organic growing "if it ain't broke don't fix it."

2.) Organic Ways to Adjust pH - For When There's a Nutrient Problem!

If you're seeing nutrient problems on your plant, the first thing to always check is the pH! Check the pH of the water that's going into your plant, as well as the runoff water that's coming out the bottom. In soil you want to maintain a pH of 6-7.

If you do notice nutrient problems, the first thing to do is check the pH of the water going in and out!

Get a pH test kit on Get a pH tester on

If your pH is outside the 6-7 range, you may need to adjust the pH to avoid further nutrient lockout on your cannabis plants. But since you're growing in organis soil, if you do want to adjust pH, you should use an organic source. 

Luckily, there are natural sources of PH Up and PH Down, many of which you can actually find around the house!

Get Organic PH Down on Amazon - Earth Juice Natural PH DownGet Organic pH Down on - Earth Juice Natural pH DownOrganic "pH Down"

Organic "pH Up"

Note: Dolomite Lime acts as a natural pH buffer and will help keep the pH constant when added to your soil during the compost process. It can also help correct acidic soil up to a certain point. If you have just realized your soil pH is too low, try to find powdered dolomite lime, as the larger chunks take longer to break down, though be careful that you don't add more than instructed, lime is "hot" (has relatively high levels of nutrients) and can burn your plant in too-high doses. The larger chunks should be okay if you're just looking for a pH buffer.

Using an inorganic pH adjuster (like the pH Up and Down that come with most pH adjustment kits, for example the General Hydroponics pH kit) may actually damage your microherd (beneficial bacteria) and can set your marijuana plants back as far as nutrient breakdown / absorption is concerned. 



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