The popularity of blueberries have caused many people to become interested in quickly adjusting the soil pH downwards. Don’t mess with your soil without having it analyzed. Submit a sample to your county extension service and have it tested. You need to have the soil re-testing regularly to monitor the situation. Blueberry plants need an acid soil in a pH range from 4.5 to 5.0 to grow well. Soil pH directly affects the life and growth of plants because it affects the availability of all plant nutrients. The soil pH needs to be adjusted one year before planting your blueberry plants.
Healthy soil produces healthy crops. Soil with the proper pH enhances soil microbial activity and frees up vital soil nutrients. This helps irrigation water move without restraint and successfully through the root zone. When the soil pH is correct blueberry plants get off to an enhanced start and enjoy superior plant vigor producing better yields and better profits.
This article discusses following ways to lower the pH of the soil and handle this issue.
- Using elemental sulfur
- Using sulfuric acid
- Using pine bark or pine needles and peat moss
- Using raised beds
- Using ammonium sulfate
Using elemental sulfur
One of the cheapest ways to lower the pH of the soil is to add and work elemental sulfur into the soil and permit soil bacteria to transform the sulfur to sulfuric acid. This will lower the pH of the soil. Using sulfur is an accepted organic way to lower the pH of the soil.
It is important to realize that this is a slow biological process and not a rapid chemical reaction. This process takes place when the bacteria are active, when the soil is warm and moist. The temperature of the soil must be above 55 degrees F for the bacteria to be active. The bacteria are inactive during the cold weather so a fall application of sulfur will have little or no affect on the soil pH when spring arrives. You should mix the sulfur thoroughly into the soil a year before planting.
The amount of sulfur essential is dependent on soil type. This is because clay and organic matter act as a buffer. They absorb and release mineral ions. A relatively small amount of sulfur is needed on sands, while soils high in clay or organic matter need much more. It is essential to apply and incorporate sulfur into the soil no less than one year before planting to permit the sulfur time to be converted into sulfuric acid and lower the soil pH before planting. The soil analysis report from the county extension service should give you information on how much sulfur to use to reduce the pH if needed.
Using sulfuric acid
Soil acidification is often achieved using sulfuric acid in commercial operations. The acidifying results of sulfuric acid on the soil are instantaneous. The rate of application is frequently one half to two tons per acre, with one ton being the most frequent rate of application.
Sulfuric acid can be used to lower the pH of the soil. Lowering the pH can improve water infiltration, increase the accessibility of nutrients, and helps soils which have crops with iron induced chlorosis symptoms. Soil tests are suggested for determining the appropriateness of soil additives and the rate at which it should be applied. Sulfuric acid may be added through the irrigation system in dilute concentrations to lower the pH of the soil.
The use of sulfuric acid can be a high risk operation and the addition of sulfuric acid to water is a violent heat-producing reaction. Concentrated sulfuric acid has a high viscosity. To handle it in safety, you need to wear a plastic apron, appropriate gloves, rubber boots, and an eye guard shielding your face. If you add water to concentrated sulfuric acid, this will cause the acid to explode and possibly splash out or fracture the container. Instead you should carefully and very slowly add concentrated acid to water, the heavier acid will blend with the water as it sinks down to the bottom of the bottle. This will heat up the solution, but not erupt. NEVER add water to the acid, always add acid to water.
The following is the procedure reported by to me one person.
“I found on the label that the quart of battery acid I purchase for putting into a battery is 33.5% sulfuric acid. I first diluted the quart of sulfuric acid by very slowly pouring it through a plastic tube into a two and a half-gallon plastic container of water. This avoided any splashing. This did not cause the container of water to heat up perceptibly. This produced a solution of 3.3% sulfuric acid which was much safer and easier to handle. I then filled a 50 gallon barrel with water and added a little at a time while checking the pH with 4.0-7.0 pH indicator strips. It took 900 ml to lower pH of the water to 4.7.”
Using pine bark or pine needles or peat moss
To lower soil pH using peat moss, it will be necessary to put approximately 2.5 pounds of peat moss into the soil for every square yard. Sawdust, leaves, wood chips, cottonseed meal, leaf mold and peat moss will also lower the pH of the soil. This is a simple organic way to lower the pH of the soil.
Using raised beds
Using raised beds instead trying to change the soil pH if it is 8 and you want to go to 5.0 is a reasonable approach. Changing the soil from an 8 to 5 pH will take a good number of years and probably the amounts of acid you would have to add would be expensive and might harm the whole yard and any existing plants. When using a raised bed you can add topsoil with compost and peat moss and then mulch it with pine needles or oak leaves or whatever mix you want to use. I think in a case like this it would be fewer headaches and not be as dangerous. In addition the use of raised beds can help avoid the chance of standing water which is detrimental to the plant.
Using ammonium sulfate
If only a small adjustment in pH is needed basic reaction fertilizers may be sufficient.
Nitrogen fertilizers containing ammonium also lowers the pH of the soil. Ammonium sulfate is an inorganic salt. It has a number of uses. The most widespread use of ammonium sulfate is as a soil fertilizer. It contains 21% nitrogen as ammonium cations (positive ions), and 24% sulfur as sulfate anions (negative ions). In fertilizer the purpose of the sulfate is to lower the pH of the soil. In addition soil acidity is produced by rain, microbial activity, and nitrogen fertilizers. Therefore, soils naturally tend to become acidic with time.
With the increasing popularity of blueberries many people have become interested in ways to quickly adjusting the pH of the soil to lower levels. You can use sulfur or sulfuric acid to lower the pH of the soil. Using peat moss, raised beds, and ammonium sulfate are also options in some cases.