Post by Tumbleweed on Jun 2, 2008 0:07:42 GMT -6
Soil 101
All about dirt!!!
The fist thing you need to know is that Loam is the best soil for growing the majority of plants.
Loam soil is composed of sand, silt, and clay in concentrations of approximately 52% or less sand, 28% to 50% silt, and 7% to 27% clay according to the USDA Soil Texture Classes Chart. I must add that there is a whole range of differing opinions about what the ratio should be which constitutes "true loam" or the "best loam" and some do not include humus in the ratio at all. On the other hand many experts say loam should have fairly equal proportions of sand, clay, silt and include humus, which I tend to agree with. So my person preference is 35% sand, 30% silt, 30% clay and 5% humus.
What makes up Humus, Clay, Sand and Silt?
USDA Soil Texture Classification system
Feel your dirt!
Not sure what kind of soil you have?
Dig down several inches and get a good handful of soil. Rub the soil between your fingers. Sandy soil is rough and gritty and when squeezed it will break apart easily. Clay soil with moisture is sticky and feels plastic-like. Once you squeeze it into a clump it will be very difficult to break it apart. Silt will have small gritty particles and it will feel slippery when wet. A good combination soil when using the squeeze test is between the sand and clay scenario.
The Jar Test
Still not sure? You can do a simple tried and true test to determine the percentages of sand, silt, clay and humus you have in your soil. Get a couple of quart-sized jars and fill the first jar about half-way with your soil sample. Your first sample should come several inches below the surface soil. Label that jar "top soil". Now dig much deeper (about 2 foot) and take your second sample filling the jar half full and label it "sub-soil". Fill both jars with water, add a teaspoon of liquid dish soap or table salt and shake, shake, shake until everything is broken up and swirling inside. Now set the jars down and let the soil settle until the water becomes clear. The sand will settle to the bottom very quickly as it is the heaviest. Several hours later the silt will settle and become the next layer. After a day or two, possibly three the clay will finally settle and organic matter (humus) will remain floating on top. Using this test you should easily be able to measure and determine the ratio of sand, silt, clay and humus in your soil.
I think it bears mentioning, if you are in a living in a fairly new construction site, you can be fairly certain your top soil was moved or disturbed and sub-soil was compacted down due to the heavy moving equipment. Depending on the site, some areas may have good top soil remaining and other areas none! So testing several areas of your property is a very good idea and it is
especially important to do the second test and go a couple feet down for a sample.
Another test you may want to do is do a percolation test.
Percolation is the downward movement of water through the soil.
Permeability is the quality of the soil that enables water to move through the profile. Permeability is measured as the number of inches per hour that water moves through the saturated soil. Terms describing permeability are:
What is the pH in Your Soil?
Now that we learned what makes up our soil we need to learn the pH. But first, we should all know what pH stands for. It stands for Potential of Hydrogen. I'm not going to get into the scientific explanation, mainly because I don't understand it well enough to explain it, but it comes down this. A pH of 7 is neutral. Anything lower then 7 means the soil is acidic and anything higher is considered an alkaline soil. The range of pH is 0 -14. It is also important to know that a pH of 5.5 is 10 times more acidic than the pH of 6.5. The same is true on the other end. A pH of 8.5 is 10 times more alkaline than a pH of 7.5. So as you can see it is crucial to know exactly what it will take to eventually bring your soil to the ideal pH for the plants you are growing or intend to grow. Most horticultural plants grow best with the pH between 6.0 and 7.5.
Generally, moist climates tend to be acidic whereas dry climates are alkaline but before you assume your soil is too acidic or too alkaline you should have it tested. Any local nursery or garden center will probably be very happy to test your soil and will give you specific instructions on how to collect your soil samples. You can also contact your county Extension Agency on the best way to collect a sample of your soil and how to go about taking in or sending a sample but a good rule of thumb is to remove the top 3 inches of soil and set this aside (you will not use this in your test). Scoop enough soil below to fill a quart zip lock bag. You'll need to label it with your name, date, sample location (city, state) and the type of plants you have growing or intend to plant. You can also buy a pH testing kit at your local nursery or garden center.
Why Plants do Poorly or Die
Before I go on about how to adjust the pH, I must stress, do not just guess your soil is too alkaline or acidic just because your state or county is known for having those properties. In addition, do not assume just because a certain plant prefers acidic or alkaline soil you should rush out and purchase some amendments. You could be making a huge mistake! In the majority of cases, when a plant is not doing well or is dying, it is very rarely because of poor nutrients or incorrect pH. In fact, the death of most plants is caused by the following:
www.crescentbloom.com/Plants/Lists/Acidic%20Soils/index.htm
If you are certain none of the above problems pertain to your ailing plant and if your pH test indicates a deficiency you can amend your soil as follows:
Lowering the pH to make it more acidic:
If your soil is alkaline, you can lower your soil's pH or make it more acidic by using several products. Sphagnum peat, elemental sulfur, aluminum sulfate, iron sulfate, acidifying nitrogen, and organic mulches are recommended amendments to add if your soil is too alkaline.
To reduce the soil pH by 1.0 point, mix in 1.2 oz of ground rock sulfur per square yard if the soil is sandy, or 3.6 oz per square yard for all other soils. The sulfur should be thoroughly mixed into the soil before planting.
Thumbs up! Sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and especially peat moss, will lower the soil pH.
Raising the soil pH to make it more alkaline
Because different soil types react in different ways to the application of lime you will have to add more lime to clay soils and
peaty soils than you will in sandy soils to achieve the same result.
To increase your pH by 1.0 point
Sandy Soils: Add 4 ounces of hydrated lime per square yard.
Loamy Soils: Add 8 ounces of hydrated lime per square yard.
Clay Soils: Add 12 ounces of hydrated lime per square yard.
Peaty Soil: Add 25 ounces of hydrated lime per square yard.
Thumbs up! Other great additions to make your soil more alkaline is by adding crushed oyster shell, crushed marble, hardwood ashes, or bone meal. Do not try to completely "correct" a problem of acidic soil in one application. Make tiny adjustments each year taking in samples each year to see how the pH has changed.
More soil info
As mentioned, soil is made up of particles of various sizes. Some are large sand grains, small sand grains, silt particles or may be microscopic flakes of clay. Sandy soils are usually well aerated and drain well but typically nutrient poor. Sand and silt cannot bind mineral nutrients whereas clay soil will bind mineral nutrients but is known to provide poor drainage. So you probably are thinking, shouldn't adding sand to clay soil help then? The answer is no, not if you don't know what you are doing.
Ideally, soil should be 50% minerals and organic matter (sand, silt, humus, clay) and the other 50% should be pore space. Keep in mind that clay flakes are microscopic and will fill in the tiniest spaces so by adding a just a little sand or small grained sand will result in a much heavier soil - something that resembles concrete. May I quote Wikpedia, "Cement is made by heating limestone with small quantities of other materials (such as clay) to 1450°C in a kiln." The most common use of (Portland) cement is in the production of concrete. Concrete is a composite material consisting of aggregate (gravel and sand), cement, and water."
en.wikipedia.org/wiki/Cement#Portland_cement
So as you can see, if you don't know exactly what makes up your soil and the percentage you may need to amend your soil, you may end up with concrete-like soil. (Take my word for it, I know.) If you are determined to make your soil into a perfect loam, keep in mind that immense amounts of large grained sand and organic matter may be needed and in some cases immense amounts of soil will need to be removed.
So the question is, how much and how?
Go big. Doing a large area is the most cost effective way to go about this. It is not recommended you amend the hole you intend to plant something in. First of all you wouldn't be purchasing in bulk but rather bags of sand or organic matter and in the long run, is expensive if you plan on planting many new plants. Secondly, a plant may go in shock or decline quickly if the root system moves beyond the amended soil.
First, calculate the area you are amending by measuring the length and width and determine the square footage. Ideally, you should use equal parts of coarse sand and coarse organic matter to amend the soil. You will need to cover the area with a 3-4 inch layer of organic matter and a 3-4 inch layer of large grained sand. Buy your sand and organic matter in bulk. It will probably be measured by the cubic yard so you'll need to figure out how much you need accordingly. See , Calculate Cubic Yards. One cubic yard will cover approximately a 10x10 feet area (100 square feet) with 3 inches of material. First spread and till the organic matter into the soil and repeat the process with the sand. Follow up with a pH test at the end of the season or the following year.
My Recommendations are:
If this article was helpful please tell a friend about this site. Thanks.
Edited to correct a typo
All about dirt!!!
The fist thing you need to know is that Loam is the best soil for growing the majority of plants.
Loam soil is composed of sand, silt, and clay in concentrations of approximately 52% or less sand, 28% to 50% silt, and 7% to 27% clay according to the USDA Soil Texture Classes Chart. I must add that there is a whole range of differing opinions about what the ratio should be which constitutes "true loam" or the "best loam" and some do not include humus in the ratio at all. On the other hand many experts say loam should have fairly equal proportions of sand, clay, silt and include humus, which I tend to agree with. So my person preference is 35% sand, 30% silt, 30% clay and 5% humus.
What makes up Humus, Clay, Sand and Silt?
- Humus is organic material that has been converted by microorganisms to a resistant state of decomposition thus becoming organic matter or humus.
- Clay soil is primarily fine-grained minerals, which show plasticity through a variable range of water content.
- Sandy soil is predominantly made up of quartz.
- Silt is composed mainly of quartz and feldspar but of a smaller size than sand.
USDA Soil Texture Classification system
| Name of soil separate | Diameter limits (mm) |
| Very coarse sand* | 2.00 - 1.00 |
| Coarse sand | 1.00 - 0.50 |
| Medium sand | 0.50 - 0.25 |
| Fine sand | 0.25 - 0.10 |
| Very fine sand | 0.10 - 0.05 |
| Silt | 0.05 - 0.002 |
| Clay | less than 0.002 |
Feel your dirt!
Not sure what kind of soil you have?
Dig down several inches and get a good handful of soil. Rub the soil between your fingers. Sandy soil is rough and gritty and when squeezed it will break apart easily. Clay soil with moisture is sticky and feels plastic-like. Once you squeeze it into a clump it will be very difficult to break it apart. Silt will have small gritty particles and it will feel slippery when wet. A good combination soil when using the squeeze test is between the sand and clay scenario.
The Jar Test
Still not sure? You can do a simple tried and true test to determine the percentages of sand, silt, clay and humus you have in your soil. Get a couple of quart-sized jars and fill the first jar about half-way with your soil sample. Your first sample should come several inches below the surface soil. Label that jar "top soil". Now dig much deeper (about 2 foot) and take your second sample filling the jar half full and label it "sub-soil". Fill both jars with water, add a teaspoon of liquid dish soap or table salt and shake, shake, shake until everything is broken up and swirling inside. Now set the jars down and let the soil settle until the water becomes clear. The sand will settle to the bottom very quickly as it is the heaviest. Several hours later the silt will settle and become the next layer. After a day or two, possibly three the clay will finally settle and organic matter (humus) will remain floating on top. Using this test you should easily be able to measure and determine the ratio of sand, silt, clay and humus in your soil.
I think it bears mentioning, if you are in a living in a fairly new construction site, you can be fairly certain your top soil was moved or disturbed and sub-soil was compacted down due to the heavy moving equipment. Depending on the site, some areas may have good top soil remaining and other areas none! So testing several areas of your property is a very good idea and it is
especially important to do the second test and go a couple feet down for a sample.
Another test you may want to do is do a percolation test.
Percolation is the downward movement of water through the soil.
Permeability is the quality of the soil that enables water to move through the profile. Permeability is measured as the number of inches per hour that water moves through the saturated soil. Terms describing permeability are:
| Very slow | less than 0.06 inch |
| Slow | 0.06 to 0.2 inch |
| Moderately slow | 0.2 to 0.6 inch |
| Moderate | 0.6 inch to 2.0 inches |
| Moderately rapid | 2.0 to 6.0 inches |
| Rapid | 6.0 to 20 inches |
| Very rapid | more than 20 inches |
What is the pH in Your Soil?
Now that we learned what makes up our soil we need to learn the pH. But first, we should all know what pH stands for. It stands for Potential of Hydrogen. I'm not going to get into the scientific explanation, mainly because I don't understand it well enough to explain it, but it comes down this. A pH of 7 is neutral. Anything lower then 7 means the soil is acidic and anything higher is considered an alkaline soil. The range of pH is 0 -14. It is also important to know that a pH of 5.5 is 10 times more acidic than the pH of 6.5. The same is true on the other end. A pH of 8.5 is 10 times more alkaline than a pH of 7.5. So as you can see it is crucial to know exactly what it will take to eventually bring your soil to the ideal pH for the plants you are growing or intend to grow. Most horticultural plants grow best with the pH between 6.0 and 7.5.
Generally, moist climates tend to be acidic whereas dry climates are alkaline but before you assume your soil is too acidic or too alkaline you should have it tested. Any local nursery or garden center will probably be very happy to test your soil and will give you specific instructions on how to collect your soil samples. You can also contact your county Extension Agency on the best way to collect a sample of your soil and how to go about taking in or sending a sample but a good rule of thumb is to remove the top 3 inches of soil and set this aside (you will not use this in your test). Scoop enough soil below to fill a quart zip lock bag. You'll need to label it with your name, date, sample location (city, state) and the type of plants you have growing or intend to plant. You can also buy a pH testing kit at your local nursery or garden center.
Why Plants do Poorly or Die
Before I go on about how to adjust the pH, I must stress, do not just guess your soil is too alkaline or acidic just because your state or county is known for having those properties. In addition, do not assume just because a certain plant prefers acidic or alkaline soil you should rush out and purchase some amendments. You could be making a huge mistake! In the majority of cases, when a plant is not doing well or is dying, it is very rarely because of poor nutrients or incorrect pH. In fact, the death of most plants is caused by the following:
- Too much water
- You are over watering
- Your soil has poor drainage
- Your soil is located where water collects
- You have clay soil.
Wait! Do not run out to buy a bag of sand to dump in the soil or steal sand from your child's sand box to amend that soil. That can be a huge mistake! Read on and I explain why further in this article.
- You are over watering
- Too little water
- Hot weather is drying the soil faster
- You have very sandy soil
- You just forget to water consistently
- Hot weather is drying the soil faster
- The presence of herbicides or weed killers
- Careful application of weed killers was not followed
- Application of weed killer was on higher ground and rain washed it into the troubled plant.
- Careful application of weed killers was not followed
- Presence of insect or disease organisms
- Lack of oxygen in the soil
- Little or no organic material added
- Too small sized sand particles
- Soil has never or seldomly been aerated
- Little or no organic material added
- The presence of nematodes
- Affected roots will be blackened, stubby and/or shriveled with little or no white feeder roots.
- Affected roots will be blackened, stubby and/or shriveled with little or no white feeder roots.
www.crescentbloom.com/Plants/Lists/Acidic%20Soils/index.htm
If you are certain none of the above problems pertain to your ailing plant and if your pH test indicates a deficiency you can amend your soil as follows:
Lowering the pH to make it more acidic:
If your soil is alkaline, you can lower your soil's pH or make it more acidic by using several products. Sphagnum peat, elemental sulfur, aluminum sulfate, iron sulfate, acidifying nitrogen, and organic mulches are recommended amendments to add if your soil is too alkaline.
To reduce the soil pH by 1.0 point, mix in 1.2 oz of ground rock sulfur per square yard if the soil is sandy, or 3.6 oz per square yard for all other soils. The sulfur should be thoroughly mixed into the soil before planting.
Thumbs up! Sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and especially peat moss, will lower the soil pH.
Raising the soil pH to make it more alkaline
Because different soil types react in different ways to the application of lime you will have to add more lime to clay soils and
peaty soils than you will in sandy soils to achieve the same result.
To increase your pH by 1.0 point
Sandy Soils: Add 4 ounces of hydrated lime per square yard.
Loamy Soils: Add 8 ounces of hydrated lime per square yard.
Clay Soils: Add 12 ounces of hydrated lime per square yard.
Peaty Soil: Add 25 ounces of hydrated lime per square yard.
Thumbs up! Other great additions to make your soil more alkaline is by adding crushed oyster shell, crushed marble, hardwood ashes, or bone meal. Do not try to completely "correct" a problem of acidic soil in one application. Make tiny adjustments each year taking in samples each year to see how the pH has changed.
More soil info
As mentioned, soil is made up of particles of various sizes. Some are large sand grains, small sand grains, silt particles or may be microscopic flakes of clay. Sandy soils are usually well aerated and drain well but typically nutrient poor. Sand and silt cannot bind mineral nutrients whereas clay soil will bind mineral nutrients but is known to provide poor drainage. So you probably are thinking, shouldn't adding sand to clay soil help then? The answer is no, not if you don't know what you are doing.
Ideally, soil should be 50% minerals and organic matter (sand, silt, humus, clay) and the other 50% should be pore space. Keep in mind that clay flakes are microscopic and will fill in the tiniest spaces so by adding a just a little sand or small grained sand will result in a much heavier soil - something that resembles concrete. May I quote Wikpedia, "Cement is made by heating limestone with small quantities of other materials (such as clay) to 1450°C in a kiln." The most common use of (Portland) cement is in the production of concrete. Concrete is a composite material consisting of aggregate (gravel and sand), cement, and water."
en.wikipedia.org/wiki/Cement#Portland_cement
So as you can see, if you don't know exactly what makes up your soil and the percentage you may need to amend your soil, you may end up with concrete-like soil. (Take my word for it, I know.) If you are determined to make your soil into a perfect loam, keep in mind that immense amounts of large grained sand and organic matter may be needed and in some cases immense amounts of soil will need to be removed.
So the question is, how much and how?
Go big. Doing a large area is the most cost effective way to go about this. It is not recommended you amend the hole you intend to plant something in. First of all you wouldn't be purchasing in bulk but rather bags of sand or organic matter and in the long run, is expensive if you plan on planting many new plants. Secondly, a plant may go in shock or decline quickly if the root system moves beyond the amended soil.
First, calculate the area you are amending by measuring the length and width and determine the square footage. Ideally, you should use equal parts of coarse sand and coarse organic matter to amend the soil. You will need to cover the area with a 3-4 inch layer of organic matter and a 3-4 inch layer of large grained sand. Buy your sand and organic matter in bulk. It will probably be measured by the cubic yard so you'll need to figure out how much you need accordingly. See , Calculate Cubic Yards. One cubic yard will cover approximately a 10x10 feet area (100 square feet) with 3 inches of material. First spread and till the organic matter into the soil and repeat the process with the sand. Follow up with a pH test at the end of the season or the following year.
My Recommendations are:
- First do the jar test to determine your soil ratios.
- Do use compost (organic material) to amend your soil before chemicals. Although only 1% of organic material will become organic matter (humus) you will find just this step improves the quality of your soil immensely!
- Decide if you are O.K. with plantings that are suited to the type of soil you have.
- If the answer is no make certain none of the conditions exist outlined in "Why Plants do Poorly" section of this article and correct those problems first.
- The best way to adjust pH is over seasons and testing each year, say in the fall.
- Only apply lime when tests show it is absolutely necessary.
- If the soil is excessively alkaline, you may want to consider building a raised bed with purchased topsoil.
- Always read and follow the manufactures recommendations when using chemical products and use appropriate protection
such as a dust mask, and gloves.
If this article was helpful please tell a friend about this site. Thanks.
Edited to correct a typo