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Even most beginner gardeners know that ericaceous compost is the way to go to maintain acidic conditions in the soil. Adding compost to regular beds or planting pots helps acid-loving plants such as rhododendrons thrive.
However, how can you be sure that the ericaceous compost you put down will last?
The truth is that ericaceous compost does lose acidity over time. This is especially true when you spread a layer of compost over a layer of regular soil, as the alkaline elements in the soil will neutralize the compost over time. You can prevent this problem by regularly checking the pH levels of your soil and renewing your ericaceous compost.
Sometimes, spreading down compost does not mean you’re done worrying about the soil conditions your plants are growing in. Here is what you need to know to ensure that your blooms continue flowering properly.
What Is Ericaceous Compost?
Before getting into the changing pH of ericaceous compost, it’s worth remembering what this compost is. Ericaceous compost is a compost made up of organic matter, including:
- Pine needles
- Rotting leaves
- Coffee grounds
- Citrus peels
Most ericaceous composts that you get at the store are loam-based mixes. Peat-based ericaceous composts used to be very popular because peat is slightly acidic, but they have been outlawed in most cases as people now understand that peat harvesting degrades the environment.
You can also make ericaceous compost at home, although it will require some trial and error to get the right pH.
Ericaceous compost has many benefits, including enriching the soil with organic nutrients and creating well-drained, moisture-enriched soil. However, its defining characteristic is its acidity.
Ericaceous compost is one of the best solutions for helping plants that need acidic soil to thrive. However, that only works for as long as the ericaceous compost is effective.
Does Ericaceous Compost Lose Acidity?
Ericaceous compost will lose acidity over time, depending on where you place it. If you put down ericaceous compost in a garden pot and plant a flower directly in the compost without adding any other soil, then it will hold on to its acidity for a long time.
Without adding additional soil to the pot, there is nothing in place to neutralize the acidity of the compost.
However, the situation is different when spreading a layer of ericaceous compost over your garden beds. When ericaceous soil mixes with regular soil, it comes in contact with materials that can neutralize its acidity and limit its effectiveness over time, especially if you are spreading it over clay soils or areas that have lots of lime. Don’t be surprised if you notice this problem.
How Can You Tell if Ericaceous Compost Has Lost Acidity?
There are a few ways that you can tell if your ericaceous compost has lost acidity and the soil is no longer at the optimum pH for the plants. One way is by observing the conditions of your ericaceous plants.
If you notice that your plants are not growing as much as they used to or are developing chlorosis, or yellow leaves, then the soil is too alkaline for them to thrive anymore.
However, you probably don’t want to wait for your plants to start suffering before taking steps to help them. A more proactive way to stay on top of the conditions of your ericaceous compost is to test the pH of your soil regularly. There are no rules on how often you should test soil pH.
However, if you know that you have ericaceous plants and that the soil below the compost has some alkaline elements, you should do so regularly so you can acidify the soil if necessary.
You can buy soil pH tests at most garden stores, then just take a sample from your bed and follow the instructions. If you don’t want to buy a soil pH test, you can make your own. Take a sample of soil from your bed, then add baking soda to it.
If the soil starts to fizzle, it is still acidic. If the reaction is less intense than it used to be or barely happens at all, then the acidity of your ericaceous compost is decreasing.
Keep in mind that while at-home soil pH tests are more accessible, they are less accurate and easier to make mistakes with if you get the ratio of soil to baking soda wrong. For complete accuracy, it’s better to trust the ones you get at the store.
What Should You Do if Your Ericaceous Compost Isn’t Acidic Anymore?
If your garden bed has a higher pH than usual when you conduct your pH test, then it is time to acidify the soil. Acidifying the soil and the ericaceous compost means adding acidic materials to the beds so you can bring the pH down again.
There are a few ways that you can do this. One is through organic methods. Adding naturally acidic materials such as pinecones or citrus peels to your ericaceous compost, mixing it, then spreading it thoroughly will bring your compost back to normal.
It might take a bit of time for your organic materials to break down and bring down the pH of your soil, so don’t wait for your plants to suffer before doing this.
You can also add other soil-acidifying materials, such as sulfur or aluminum sulfate. Most of these work best when the soil is warm, so don’t spread during winter.
Finally, you can take steps to prevent ericaceous compost from losing too much acidity. Spreading down a layer of mulch will protect the compost from alkaline elements in the soil. Watering with rainwater instead of tap water and avoiding plant food with alkaline elements are other things you can do to protect your compost.
Final Thoughts
Ericaceous compost does lose its acidity over time, particularly if you spread it over alkaline soil. However, you can reacidify your compost and prevent it from neutralizing too much if you use the right plant food and water.
Sources
- https://www.rhs.org.uk/soil-composts-mulches/acidifying-soil
- https://horticulture.co.uk/ericaceous-compost/#:~:text=If%20you%20put%20the%20ericaceous,cones%20if%20you%20need%20to.
- https://www.gardenersworld.com/how-to/grow-plants/ericaceous-compost/
- https://www.gardenshedreviews.co.uk/all-about-ericaceous-compost/
