What Is Soil pH and What Does It Mean to the Gardener? (thespruce.com)
Written by Marie Iannotti
What Is Soil pH?
A lot of emphasis is put on the pH of garden soil. Soil pH is a measurement of the alkalinity or acidity of soil. Soil pH is measured on a scale of 1-14, with 7 as the neutral mark.
Technically, pH is a gauge of the hydrogen-ion concentration (potential Hydrogen) in a substance. For the gardener's needs, it is enough to know whether your soil is alkaline or acidic because certain nutrients can only be accessed by plants when the soil pH falls into an acceptable range and no amount of fertilizer is going to improve their health until the pH has n adjusted.
Most plants prefer a somewhat neutral pH, anything from 6.2 to 7.0. However there are many plants that are more specific in their pH needs, such as blueberries and azaleas, which like a very acidic soil, and lilacs and clematis, that prefer a more alkaline soil. There are even some, like hydrangeas, that change flower color depending on the soil's pH.
Generally speaking, if your plants are growing healthy, with no signs of problems, your soil pH is probably in an acceptable range. However if your plants are looking stressed, discolored, or not growing vigorously, one of the first things you should do is test your pH.
How to Know What Your Soil pH Is?
You have a few options, when it comes to testing your soil's pH. There are many do-it-yourself testing kits available in local garden centers. Most do a good job of at least telling you which end of the scale your soil is at and that may be all you need for making adjustments.
For a more accurate measure, you can send a soil sample to a lab or bring it into your local Cooperative Extension office. They will charge a small fee, but you will have a more precise idea of where yr soil stands.
If you simply want to know if you soil leans acidic or alkaline, here's a quick soil pH test you can do at home. It will only give you a ballpark reading, but it's a good place to start.
How to Correct Your Soil's pH
It takes time to change the pH of soil, often months, and it will need to be an ongoing process. Left alone, soil will eventually revert back to its natural pH. However, you won't have to adjust all your soil, unless it is extremely acidic or alkaline. You can adjust just the areas where you are growing plants that need a different pH.
Basically the pH of acidic soil is raised by adding lime. The pH of alkaline soil is lowered by adding some form of sulfur. How much to add depends on your current soil pH, the texture of your soil (clay, sand, humus) and what you will be growing. Your soil test kit or the report you get from the lab or extension should tell you what you need to do. And here's a quick way to test your soil's texture.
Once you get your soil pH into an acceptable range, you will need to reapply either lime or sulfur on a regular basis, to keep it there. This is best done in the fall or off season, so that the amendment has time to work its way into the soil slowly, without harming plant roots. It's also a good idea to re-test your soil about every 3 years, to see if adjustments need to be made. Of course, your plants will have the final say. If they are going well, it's hard to argue for changes.
PH and Growing Cannabis
Ideal Ph Levels for Growing Cannabis
When growing cannabis in soil the Ph should usually be around the 5.8 – 6.4 mark. When growing in pots, a single Ph reading for each pot is advised. When growing outdoors it is best to take two or three Ph measurements from different areas of the grow area. If you have a large growing area, you may have to adjust the Ph in various parts to different levels.
Because pH imbalance makes it difficult for the plant to absorb nutrients with its roots. Whether a cannabis plant is planted in soil, coco, or hydro, pH levels need to be maintained to optimal levels. For simplicity we will simply use “Soil” to stand for all three.
When the soil is too acidic, cannabis plants will begin to lose their ability to absorb nutrients through their roots. As the soil gets more and more acidic, the plant will lose all ability to feed and eventually become toxic.
Similarly, when the soil becomes too alkaline, phosphorus and calcium can’t be broken down which stunts the plant’s growth. If the soil becomes too alkaline, the plant will be subjected to root damage.
However cannabis plants prefer an acidic soil so problems start to arrive around a pH of 6.5, which is slightly acidic but is not acidic enough for the plant’s liking. You want the cannabis plant to be able to use all the phosphorus it can at all times, but especially during flowering. Phosphorus and Potassium are required in high amounts during the mid flowering phase so better to be slightly too acidic than slightly too alkaline.
Cannabis Soil pH Levels
4.0 and below: Toxic
4.0-5.3: Poor Nutrient Uptake
5.3-5.8: Good pH Level
5.8-6.3: Perfect pH Balance
6.4-7.0: Acceptable pH Level
7.1-8.4: Poor Nutrient Uptake
8.5 and Above: Root Damage
Check the Ph every couple of weeks to avoid lockout from salt-based fertilizer buildup
Most nutrients will cause a Ph change in the soil. Adding fertilizer to the soil often results in a lower, more acidic Ph. As time goes by, the amount of salts produced by the breakdown of nutrients in the soil causes the soil to become increasingly acidic and eventually the concentration of these salts in the soil will hurt the plant, affecting production and destroying the leaves. As the plant gets older its roots also become less efficient in supplying food to the leaves.
Written by Marie Iannotti
What Is Soil pH?
A lot of emphasis is put on the pH of garden soil. Soil pH is a measurement of the alkalinity or acidity of soil. Soil pH is measured on a scale of 1-14, with 7 as the neutral mark.
Technically, pH is a gauge of the hydrogen-ion concentration (potential Hydrogen) in a substance. For the gardener's needs, it is enough to know whether your soil is alkaline or acidic because certain nutrients can only be accessed by plants when the soil pH falls into an acceptable range and no amount of fertilizer is going to improve their health until the pH has n adjusted.
Most plants prefer a somewhat neutral pH, anything from 6.2 to 7.0. However there are many plants that are more specific in their pH needs, such as blueberries and azaleas, which like a very acidic soil, and lilacs and clematis, that prefer a more alkaline soil. There are even some, like hydrangeas, that change flower color depending on the soil's pH.
Generally speaking, if your plants are growing healthy, with no signs of problems, your soil pH is probably in an acceptable range. However if your plants are looking stressed, discolored, or not growing vigorously, one of the first things you should do is test your pH.
How to Know What Your Soil pH Is?
You have a few options, when it comes to testing your soil's pH. There are many do-it-yourself testing kits available in local garden centers. Most do a good job of at least telling you which end of the scale your soil is at and that may be all you need for making adjustments.
For a more accurate measure, you can send a soil sample to a lab or bring it into your local Cooperative Extension office. They will charge a small fee, but you will have a more precise idea of where yr soil stands.
If you simply want to know if you soil leans acidic or alkaline, here's a quick soil pH test you can do at home. It will only give you a ballpark reading, but it's a good place to start.
How to Correct Your Soil's pH
It takes time to change the pH of soil, often months, and it will need to be an ongoing process. Left alone, soil will eventually revert back to its natural pH. However, you won't have to adjust all your soil, unless it is extremely acidic or alkaline. You can adjust just the areas where you are growing plants that need a different pH.
Basically the pH of acidic soil is raised by adding lime. The pH of alkaline soil is lowered by adding some form of sulfur. How much to add depends on your current soil pH, the texture of your soil (clay, sand, humus) and what you will be growing. Your soil test kit or the report you get from the lab or extension should tell you what you need to do. And here's a quick way to test your soil's texture.
Once you get your soil pH into an acceptable range, you will need to reapply either lime or sulfur on a regular basis, to keep it there. This is best done in the fall or off season, so that the amendment has time to work its way into the soil slowly, without harming plant roots. It's also a good idea to re-test your soil about every 3 years, to see if adjustments need to be made. Of course, your plants will have the final say. If they are going well, it's hard to argue for changes.
PH and Growing Cannabis
Ideal Ph Levels for Growing Cannabis
When growing cannabis in soil the Ph should usually be around the 5.8 – 6.4 mark. When growing in pots, a single Ph reading for each pot is advised. When growing outdoors it is best to take two or three Ph measurements from different areas of the grow area. If you have a large growing area, you may have to adjust the Ph in various parts to different levels.
Because pH imbalance makes it difficult for the plant to absorb nutrients with its roots. Whether a cannabis plant is planted in soil, coco, or hydro, pH levels need to be maintained to optimal levels. For simplicity we will simply use “Soil” to stand for all three.
When the soil is too acidic, cannabis plants will begin to lose their ability to absorb nutrients through their roots. As the soil gets more and more acidic, the plant will lose all ability to feed and eventually become toxic.
Similarly, when the soil becomes too alkaline, phosphorus and calcium can’t be broken down which stunts the plant’s growth. If the soil becomes too alkaline, the plant will be subjected to root damage.
However cannabis plants prefer an acidic soil so problems start to arrive around a pH of 6.5, which is slightly acidic but is not acidic enough for the plant’s liking. You want the cannabis plant to be able to use all the phosphorus it can at all times, but especially during flowering. Phosphorus and Potassium are required in high amounts during the mid flowering phase so better to be slightly too acidic than slightly too alkaline.
Cannabis Soil pH Levels
4.0 and below: Toxic
4.0-5.3: Poor Nutrient Uptake
5.3-5.8: Good pH Level
5.8-6.3: Perfect pH Balance
6.4-7.0: Acceptable pH Level
7.1-8.4: Poor Nutrient Uptake
8.5 and Above: Root Damage
Check the Ph every couple of weeks to avoid lockout from salt-based fertilizer buildup
Most nutrients will cause a Ph change in the soil. Adding fertilizer to the soil often results in a lower, more acidic Ph. As time goes by, the amount of salts produced by the breakdown of nutrients in the soil causes the soil to become increasingly acidic and eventually the concentration of these salts in the soil will hurt the plant, affecting production and destroying the leaves. As the plant gets older its roots also become less efficient in supplying food to the leaves.
