Testing the pH of soil
- Thread starter Gundark
- Start date
and try to catch the early runoff, just as it starts coming out of the bottom, as that would be the most accurate.
Sungod
New Member
What is the reason for testing run off and not the soil directly?
Testing the runoff is much more accurate because it is an indication of how your water, nutrients, and grow medium are interacting chemically.
The runoff represents what's going on in the entire root zone a lot better than just doing a spot check in one area or checking a single soil sample. Even if you checked in more than one spot, the runoff would more accurately represent the average pH of your soil.
There are 3 measurements that are important to know when you are caring for plants growing in a soil or soilless medium:
The first is the pH of your source water.
The second is the pH of your nutrient solution after the nutrients are added.
The last is the pH of your soil, but that's the hardest one to measure accurately. You can't just stick a pH meter in the dirt and get an accurate reading, and the cheap metal-probed meters are usually not all that precise.
The runoff represents what's going on in the entire root zone a lot better than just doing a spot check in one area or checking a single soil sample. Even if you checked in more than one spot, the runoff would more accurately represent the average pH of your soil.
There are 3 measurements that are important to know when you are caring for plants growing in a soil or soilless medium:
The first is the pH of your source water.
The second is the pH of your nutrient solution after the nutrients are added.
The last is the pH of your soil, but that's the hardest one to measure accurately. You can't just stick a pH meter in the dirt and get an accurate reading, and the cheap metal-probed meters are usually not all that precise.
Sungod
New Member
So you water with ph corrected water of say 7.0 let it go through the organic mater in the soil which will lower the ph of the water. Then take a reading of the water as it if first coming out. If cannabis optimally at 6.5-6.8, is that what I'm aiming my run off to be or is there another range that I should be trying to achieve with my run off?
Screwnuts33
Member of the Month 3rd Place Winner (Dec 09')
You want your water/nutes going in at 6.2-6.8 and your runoff water to be above 6.0. That is the ideal. Some strains may require higher/lower numbers to be happy but most will thrive in that range.
wifecaretaker
New Member
So what if everything is peachy going in but ends up 5.0 coming out. How do you correct? This senario is an older flowering lady, who cannot be transplanted.
wct
wct
this should be helpful:
"Adjusting your soil pH :
Once you have determined the pH of your soil with a good tester, you can amend the soil if needed to accommodate the plants in your garden using inexpensive materials commonly available at your local garden center.
Adjust soil pH slowly over several days time, and check pH often as you go. Radical changes in pH may cause osmotic shock damage to the roots.
Raising soil pH : (to make it more alkaline)
It is generally easier to make soil mixes more alkaline than it is to make them more acidic. The addition of dolomite lime, hardwood ash, bone meal, crushed marble, or crushed oyster shells will help to raise the soil pH.
In soil: add dolomite limestone to the soil; use small amounts of hydrated lime.
Lowering soil pH : (to make it more acidic)
If your soil needs to be more acidic, sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and especially peat moss, will lower the soil pH.
Stabilizing pH with Dolomite lime
The best way to stable PH is by adding 1 ounce of Dolomite Lime per 1 gallon of planting soil.
Dolomite Lime is available in garden nurseries. Buy the fine Dolomite powder (There may be several kinds of Dolomite like Rough, Medium, Fine)
Dolomite Lime has been a useful PH stabilizer for years, since it has a neutral PH of 7 when added to your soil it stabilizes your soil at PH 7.
Mix the dry soil medium and dolomite together really well, give the mix a good watering then after the water has had chance to settle and leech into the soil a bit give the mix a really good stir. Then water the soil/lime mix and give it another stir
Best plan is to mix fine dolomite lime into your mix before planting. Fine Dolomite will help stabilize your pH; however, if the ph becomes unstable or changes, you can then use Hydrated Dolomite Lime. Add some of the hydrated lime to luke warm water and give it a good stir then water your plants with it. Give the plants a good watering with this hydrated lime added and your PH should fall or rise back to 7"
"Adjusting your soil pH :
Once you have determined the pH of your soil with a good tester, you can amend the soil if needed to accommodate the plants in your garden using inexpensive materials commonly available at your local garden center.
Adjust soil pH slowly over several days time, and check pH often as you go. Radical changes in pH may cause osmotic shock damage to the roots.
Raising soil pH : (to make it more alkaline)
It is generally easier to make soil mixes more alkaline than it is to make them more acidic. The addition of dolomite lime, hardwood ash, bone meal, crushed marble, or crushed oyster shells will help to raise the soil pH.
In soil: add dolomite limestone to the soil; use small amounts of hydrated lime.
Lowering soil pH : (to make it more acidic)
If your soil needs to be more acidic, sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and especially peat moss, will lower the soil pH.
Stabilizing pH with Dolomite lime
The best way to stable PH is by adding 1 ounce of Dolomite Lime per 1 gallon of planting soil.
Dolomite Lime is available in garden nurseries. Buy the fine Dolomite powder (There may be several kinds of Dolomite like Rough, Medium, Fine)
Dolomite Lime has been a useful PH stabilizer for years, since it has a neutral PH of 7 when added to your soil it stabilizes your soil at PH 7.
Mix the dry soil medium and dolomite together really well, give the mix a good watering then after the water has had chance to settle and leech into the soil a bit give the mix a really good stir. Then water the soil/lime mix and give it another stir
Best plan is to mix fine dolomite lime into your mix before planting. Fine Dolomite will help stabilize your pH; however, if the ph becomes unstable or changes, you can then use Hydrated Dolomite Lime. Add some of the hydrated lime to luke warm water and give it a good stir then water your plants with it. Give the plants a good watering with this hydrated lime added and your PH should fall or rise back to 7"
