ppm Charlie
Well-Known Member
Hello, I'm "ppm Charlie". I just joined here. I interested in cannabis cultivation and various recreational and medicinal products and uses. In my youth, I used 420 for recreational and medical purposes. For the last 20 yrs, because of employment requirements, I had to refrain from the wake and bake. I am now retired and plan to reestablish my past youthful 420 ways. In my long ago past, I had a successful grow. In those days, before legalization in many states, things were quite hush-hush and sometimes dangerous. Hopefully, that place and time is now in the distant past.
A month ago, I began a new grow (courtesy of our Canadian friends and their wonderful seed banks). When my new grow is harvest and cured, I plan to use 420 for recreational and medical purposes again. I do not own any particular hemp products, except for twine I use to bind-up the vegetable garden plants. I am politically motivated to help efforts to legalize hemp and cannabis products in my backward-thinking area of the southern USA. Hopefully, one day soon that dream will come true.
For my new grow, I am using a "home-brewed" peat-perlite soilless mix. The mix includes bacterial inoculation (mycorrhizal inocculum) for healthy root growth and increased nutrient uptake and dolomite powder for pH balance. I am adding dolomite powder to the mix to raise the pH to the correct pH level of 5.8-6.2 (the peat-perlite mix started around pH=4.5 before the dolomite was added) .
I had some thoughts on soil pH and the measurement of soil pH.
I do not use a "soil pH meter" to measure soil pH because those types of soil testing devices are nearly useless. I am testing my mix using the "slurry" method for measuring the pH of a soil sample. The method is described many places in detail online, however, for me, I measure-out about 3/4 of a soil sample by volume into a clean glass jar and add bottled water to the top of the soil to make a slurry. I shake vigorously, wait 10 minutes and use a calibrated and inexpensive pH probe to measure the slurry pH.
I use the "Wally's World" store's bottled water (has a blue label and cap and is marked "purified drinking water", rhymes with "hams") because it is a down-and-dirty substitute for RO water. "Ham's" bottled water is easily obtainable, RO derived, near neutral in pH and has very low in TDS (as shown here: Sam’s Choice Water Test | Bottled Water Tests - TestAqua.com). It makes a great substitute for distilled water that can vary in quality, pH and TDS. Test it for yourself if not convinced. I tested it and found the "Ham's" purified drinking water at pH levels ranging from 6.8 to 7.2.
Regarding the "right" choice of water for soil pH slurry testing, I believe the water should be nearly "neutral" (pH=7) and low in TDS so as not to skew the soil sample pH one way or the other. I found distilled bottled water is not that good a choice since the pH and TDS of the water can vary significantly (author's personal experimentation, 2021). Ideally, the pH of RO water is 7.0 (i.e. "neutral" pH). In fact, RO derived water is not pH=7 (generally) for very long. As soon as RO water is produced and left in contact with the CO2 in the air around us it starts to immediately change in pH, gradually, to eventual values between 5.5 to 5.8 pH range (Why Reverse Osmosis Water is Acidic?).
The soilless mix I prepared used pre-moistened peat (65%) + perlite (35%) by volume (7.5gals total, or, 1 cu.ft.), including bacterial inoculation and 10 tablespoons of powdered dolomite. A soil slurry test method of this concoction registered pH=5.95 using the the pocket pH probe and using "Wally World" bottled water. That is right in the center of my goal of 5.8-6.2 (your results may vary slightly depending on the brand of peat used). An NCSU cannabis study indicated this is the proper pH for soilless mix for best results (New Research Results: Optimal pH for Cannabis). This is the soilless media mix preparation I will use for cultivation of my 420. Others have found similar results (see "Dolomitic Lime" section at: Amending Peat for Cannabis – Zombie Gardens). Now that I have found an adequate soilless prep method using the peat and perlite stock I am using, I can prepare additional mix with more confidence regarding final soilless media pH (I will still test it though and make any necessary adjustments).
While there is no "true-blue" method of soil sample pH preparation and measurement, I believe I have done the best I can. Does anyone have thoughts on preparing soilless media for pH soil testing? I would be grateful for any input.
A month ago, I began a new grow (courtesy of our Canadian friends and their wonderful seed banks). When my new grow is harvest and cured, I plan to use 420 for recreational and medical purposes again. I do not own any particular hemp products, except for twine I use to bind-up the vegetable garden plants. I am politically motivated to help efforts to legalize hemp and cannabis products in my backward-thinking area of the southern USA. Hopefully, one day soon that dream will come true.
For my new grow, I am using a "home-brewed" peat-perlite soilless mix. The mix includes bacterial inoculation (mycorrhizal inocculum) for healthy root growth and increased nutrient uptake and dolomite powder for pH balance. I am adding dolomite powder to the mix to raise the pH to the correct pH level of 5.8-6.2 (the peat-perlite mix started around pH=4.5 before the dolomite was added) .
I had some thoughts on soil pH and the measurement of soil pH.
I do not use a "soil pH meter" to measure soil pH because those types of soil testing devices are nearly useless. I am testing my mix using the "slurry" method for measuring the pH of a soil sample. The method is described many places in detail online, however, for me, I measure-out about 3/4 of a soil sample by volume into a clean glass jar and add bottled water to the top of the soil to make a slurry. I shake vigorously, wait 10 minutes and use a calibrated and inexpensive pH probe to measure the slurry pH.
I use the "Wally's World" store's bottled water (has a blue label and cap and is marked "purified drinking water", rhymes with "hams") because it is a down-and-dirty substitute for RO water. "Ham's" bottled water is easily obtainable, RO derived, near neutral in pH and has very low in TDS (as shown here: Sam’s Choice Water Test | Bottled Water Tests - TestAqua.com). It makes a great substitute for distilled water that can vary in quality, pH and TDS. Test it for yourself if not convinced. I tested it and found the "Ham's" purified drinking water at pH levels ranging from 6.8 to 7.2.
Regarding the "right" choice of water for soil pH slurry testing, I believe the water should be nearly "neutral" (pH=7) and low in TDS so as not to skew the soil sample pH one way or the other. I found distilled bottled water is not that good a choice since the pH and TDS of the water can vary significantly (author's personal experimentation, 2021). Ideally, the pH of RO water is 7.0 (i.e. "neutral" pH). In fact, RO derived water is not pH=7 (generally) for very long. As soon as RO water is produced and left in contact with the CO2 in the air around us it starts to immediately change in pH, gradually, to eventual values between 5.5 to 5.8 pH range (Why Reverse Osmosis Water is Acidic?).
The soilless mix I prepared used pre-moistened peat (65%) + perlite (35%) by volume (7.5gals total, or, 1 cu.ft.), including bacterial inoculation and 10 tablespoons of powdered dolomite. A soil slurry test method of this concoction registered pH=5.95 using the the pocket pH probe and using "Wally World" bottled water. That is right in the center of my goal of 5.8-6.2 (your results may vary slightly depending on the brand of peat used). An NCSU cannabis study indicated this is the proper pH for soilless mix for best results (New Research Results: Optimal pH for Cannabis). This is the soilless media mix preparation I will use for cultivation of my 420. Others have found similar results (see "Dolomitic Lime" section at: Amending Peat for Cannabis – Zombie Gardens). Now that I have found an adequate soilless prep method using the peat and perlite stock I am using, I can prepare additional mix with more confidence regarding final soilless media pH (I will still test it though and make any necessary adjustments).
While there is no "true-blue" method of soil sample pH preparation and measurement, I believe I have done the best I can. Does anyone have thoughts on preparing soilless media for pH soil testing? I would be grateful for any input.
