Lime has an effect on the soil by raising the pH and correcting the acidity.
Lime is also probably the most economical way to add calcium or magnesium.
Good balanced pH is vital to plant health and yield.
However, the addition of lime can also disrupt the balance of existing nutrients and potentially harm your plants.
USDA Organic Rules specify that Certified Organic producers cannot use either burnt-lime or hydrated-lime only. But this rule does NOT apply to organic gardeners at home. So if you have a small backyard garden and want to add lime, you are free to do so.
Why Don’t Organic Gardeners Use Lime?
Anytime you add any foreign substance to your soil (other than compost or organic waste), you risk disrupting the biological community developed in your garden.
Perhaps the greatest significant risk is killing many of the beneficial bacteria responsible for making nutrients available to your plants.
Burnt lime might kill some beneficial bacteria in your soil, and, in some cases, it can burn plant roots.
Hydrated lime can also leach nutrients beyond the reach of plant roots.
A heavy accumulation of lime can cause poor land productivity.
This process typically occurs over an extended time, and often wouldn’t appear until at least three years. Usually, you don’t notice anything in the first year.
When high accumulation of lime occurs, plants are not able to utilize the nutrients needed.
Excessive salinity can also accumulate in your soil.
As a consequence, growth decreases, and you start to notice the yellowing of leaves, which is called chlorosis.
Lime is dangerous to you.
Therefore, lime should always be handled with either additional precautions for your skin, in your eyes, and or any applications that would require applicable safety material.
Particularly if the lime was either burnt or hydrated lime.
| Advantages of Using Lime | Disadvantages of Using Lime |
|---|---|
| Enhancing the soil’s physical, and biological qualities | Excessive limewater might limit root development and produce tip edema owing to hydrolysis. |
| Improved nitrogen-fixing by legumes | Nutrients such as iron, zinc, phosphorus and, manganese become unavailable to the crop if the soil becomes excessively alkaline. |
| Increasing nutrient availability to plants | It can limit the availability of micronutrients such as Zn, Fe, and others. |
| lowering harmful levels in the soil | It has an antagonistic impact on the availability of phosphorus and potassium. |
| Increasing the efficacy of certain herbicides | It has negative environmental impacts. |
| Crops are supplied with calcium, magnesium, and other minerals. |
Using Lime Pros & Cons
Why Organic Gardeners Should Use Lime
The ideal moment to use lime is when you desire to increase your soil pH.
If you are seeing slow growth and the leaves of your plants are turning yellow, it may mean your soil is too acidic.
When soil is too acidic:
- It decreases the availability of of some important nutrients like phosphorus.
- And it increases the availability of other nutrients to toxic levels (such as aluminum and manganese).
The pH raised by the lime reduced these levels to a neutral pH.
Liming is a key part of soil fertility.
Lime is a soil amendment that reduces and neutralizes soil acidity, which helps beneficial microbes and earthworms thrive.
These microorganisms are important because they decompose organic debris and keep nutrients cycling in the soil.
Agricultural lime (calcium-containing product mined from limestone, gypsum, or dolomite):
- Raises soil pH
- Reduces the solubility of toxic components
- And facilitates nutrient uptake by plant roots
By adding lime to our plants, we can reduce and neutralize manganese and iron levels responsible for soil acidity and improve soil pH.
Reducing manganese and iron levels in turn can decrease the potential for the toxic levels in our plants to increase their performance and grow faster.
Finally, lime aids the biological nitrogen fixation of legumes and overall microbial activity.
How Should Organic Gardeners Use Lime?
Soil quality is an important aspect of plant production.
Plants significantly rely on the soil’s pH balance.
As soil turns excessively acid or is lacking in lime, the yield will be significantly decreased.
As a result of these acid conditions, plants show substantial nutritional deficiencies, leading to reduced yields.
There is a way to monitor and remedy an acidic soil condition. When the soil has gone acidic, you should apply lime.
In this way, you can apply lime to an acidic soil anytime you’d like.
The only thing is that it is best to apply lime when you are preparing soil.
The fall is particularly good since it allows time for the soil to incorporate all of the lime that you applied, that soil should be ready by spring for planting.
The soil will recommend the amount of lime required, based on its original pH. If you do not test the soil for pH properly, estimating an amount is a trial and error process.
You can test your soil using a home pH test kit, but this does not test for soil type.
The results of an analysis from a competent soil testing laboratory consist of recommendations adjusted specifically to the needs of your soil.
Which Lime Should Organic Gardeners Use?
Organic gardeners ought to know about two kinds of lime:
- Agricultural lime
- Dolomite lime
Both types of lime contain calcium, but dolomite lime also includes magnesium.
While adding lime will add these nutrients to your soil, it is primarily used to change soil pH.
Dolomite Lime
Dolomite lime (calcium magnesium carbonate) consists of roughly 20% calcium and 10% magnesium.
These minerals can regulate soil pH and supply essential nutrients to plants.
Sometimes dolomite is high in sodium, but it shouldn’t exceed 0.2%. An abundance of sodium can change the salinity of your soil and harm your plants.
To apply dolomite, you should first take a reading on your soil pH. The ideal range for most plants is a pH between 6.0 and 7.4.
If the soil is a pH of 5.9 or below, it is too acidic and dolomite lime needs to be added.
When dolomite garden lime is purchased, it is usually crushed and can be either coarse or ultra-fine, or put into pellet form, which is not necessary and only complicates the application.
Be sure to check the requirements of your plants since some plants e.g. blueberries prefer acidic soils with lower pH; so, be sure before the application of dolomite.
However, it is commonly recognized that adding lime at a rate of 250 mL (1 cup) per 50 sq. ft. is acceptable.
Agriculture Lime
Calcium carbonate, or agricultural lime, is simply limestone or chalk that has been crushed and is used to change the acidity of your soil.
Agricultural lime is utilized because it has a high concentration of calcium, which will help buffer the pH of the soil.
Agricultural lime also has the capability of helping plants absorb important minerals found in the soil.
Agricultural lime is generally distributed in its pure, dry “calcitic” form, meaning that it is mostly calcium carbonate.
Good news: the benefits of agricultural lime is that once it is thoroughly and well integrated into the soil it should not have to be reapplied again. Although, there may be time involved before the ag lime can effectively begin to change the pH of the soil.
Final Thoughts
The use of lime is highly debated. Some people will say that it is a positive thing to do. Others will argue that it does more harm than good.
For example, experts claim that lime can shift the balance of nutrients.
They typically call for people to use organic matter and let nature do everything. Consequently, the USDA Organic Rules do not allow Certified Organic producers to use lime.
However, liming is an easy way to raise your soil’s pH and one of the most effective ways of doing so. Therefore, if you are a subsistence organic farmer, you certainly can lime your soil.