Does Too Much Compost Hurt Your Plants? (Answered)


Local gardeners have long known that compost is an essential ingredient in a healthy, productive garden. It provides the nutrients to feed plants and helps prevent soil erosion and water runoff. Many people do not know how much compost to add, and too much of it can hurt their garden.

Compost fosters bacteria that are used for breaking down organic matter. However, excessive amounts will cause it to be anaerobic. Applying too much compost to plants will cause them to be more prone to diseases, making it necessary to apply only one inch of compost per year on top of your plants.

In the next few sections, we will be talking about how to properly prevent the chances of over composting your plants, the ratios of compost that you give for best results as well as dilution tips and tricks that you can look into to make your compost aid the thriving process of your garden.

Does Too Much Compost Hurt Your Plants?

Compost is a great way to add nutrients and improve soil quality. It can also improve crop yields, which is why many people choose to use it. The benefits of composting are undeniable, but there are some drawbacks as well.

Experts suggest that you need only add one inch of compost or soil on top of your plants, which is about how much the average person produces for a year.

Information is like compost; it does no good unless you spread it around.

Eliot Coleman

It is because too much compost can hurt your plants by making them less healthy and more prone to disease.

4 Ways Too Much Composting Can Hurt Your Plants

The problem with composting is that too much of it can hurt your plants. Here are five ways too much composting can affect your plants:

1. Compost releases ammonia, and a high level of ammonia in the soil will quickly deplete the oxygen supply that plants need to thrive.

2. Too much nitrogen in the soil from compost causes an increase in competition for other nutrients.

3. Compost contains salts like sodium and chloride, which can build up and alter the pH balance of the soil.

4. Excessive amounts of nitrogen in the form of compost or fertilizers attract weeds that will crowd out or kill desired plant species.

Its effects on the well-being of plants will be further described in detail in the next section.

How Will Too Much of Compost Affect Plant Growth?

Composting has many positive effects on plants, such as eliminating toxins, encouraging plant growth, and improving soil quality. However, too much can have effects on plants.

It can decrease the amount of oxygen in the soil, which is necessary for root growth.

There is the potential to introduce pathogens to plants that are not resistant to them-such as from meat scraps or dirty water.

How too much compost affects the roots of the plants

The roots of a plant need to grow and spread through the soil to grow strong and healthy. Excess nitrogen can cause the roots to grow too fast and become thin, fragile, or even die.

Excess nitrogen is one of the most common nutrient deficiencies in plants. It causes an imbalance between plant uptake and the availability of nitrate or ammonium ions from fertilizers, manures, or other sources.

Adding too much compost cause underdeveloped roots

Too much can lead to unhealthy plants because it will create too many nutrients and make the soil acidic. It will, in turn, cause underdeveloped roots and a lack of chlorophyll production, which means that plants will have a hard time absorbing sunlight for photosynthesis.

How too much compost affects the leaves of the plants

The excess nitrate could lead to changes in leaf color.

The leaves may show yellowing between veins on younger leaves, while older leaves may have a red cast on their lower surfaces.

The excess nitrates could also cause stunted growth and brownish-orange tinted young foliage that eventually dies back when exposed to light for an extended period.

How too much compost affects the soil and the plant

The main problem with too much compost is that the soil will not contain enough air and water. It can cause the roots to rot, and the plant may start to wilt.

It is highly recommended that you use no more than 25% compost in your mixes.

If you mix too much compost with healthy soil, it can impact plant growth. Adding compost, especially the uncured ones, will give the plant 7 times more phosphorus content than it needs, which is deadly. This is covered in my recent article on whether you can add too much compost into the soil, which covers the disastrous effects of adding too much compost to the soil and the composting process stages for better understanding.

How to know if you are adding too much compost to your plant

There are many ways to tell when you give your plants too much compost for a prolonged period. If you notice that the soil around the plant looks dry and dusty, smells bad, or has an odor.

You need to pay attention to the number of pests and bugs that visit or live on your plants, as predators will likely eat them due to increased food source availability.

How To Tell if Your Garden Needs More or Less Compost

Adding too much compost can lead to a buildup of nitrogen which causes ammonium compounds to be released into the air, leading to hazardous airborne conditions.

If you notice that your plants are having difficulty growing, or if you only need to improve the soil quality in your garden, you can use compost.

The smell of decay is a telling sign for knowing if you need more or less compost

One way to tell if you need more or less compost is by digging down a few inches into the ground, pulling up some dirt, and smelling it for any signs of decay.

If decay smell is absent, then it is time for more compost!

The thing to note is that it can be difficult to tell when your pile has enough compost because the absence of smell does not necessarily indicate composted pile.

What To Do When Your Garden Has Too Much Compost

Composting can be a great way to get rid of all those scraps that one might have. But, if you add too much, there might not be enough air to help the food break down, and it will start to smell.

If you find that your composting pile is starting to smell like rotten eggs or ammonia and is heating up, you may have too much compost.

These are signs that the pile has lost its oxygen supply and needs some air. If you see these symptoms, you should go ahead and turn the compost with a pitchfork or shovel to release the air pockets.

How to use your excess compost

Excess of it is often a problem for gardeners. Let us explore three different solutions, starting with the most complicated and working our way down to the simplest:

  • Make a raised bed and use it as a container for excess compost
  • Add it at the bottom of your planting hole when you plant new plants

Now that we have talked about what to do with more than enough compost let us talk about diluting them to cause less harm in the garden and be used on more plants.

Tips for Diluting Excess Compost in Your Garden

Compost that is too rich will dampen the soil and smother plants. Diluting it that is too rich in nutrients is easy to do, and it will ensure a healthy environment for your plants.

Dilution ratio for composting in your garden

We recommend adding 1-2 parts water to every part of the pile when fertilizing it.

One way to dilute compost is to add fresh manure or a few handfuls of straw.

It will make it less smelly and more palatable for your plants. Another way is to add white peat moss, which breaks down faster than other types of material and will also break down the nutrients in the compost.

The Process of Adding the Right Compost to Your Garden Soil

The process of adding more or less compost to your garden soil is a lot like cooking. The ingredients you add to compost determine how the result tastes and smells.

Adding too much of it can be detrimental to your garden and can stunt plant growth. As a general rule, consider adding no more than 1 inch of uncompounded material to the existing layer of soil in your garden.

How to make compost – the proper way

The process takes time, and it is best to be mindful of the conditions to optimize the composting process.

The Process:

1) Layering-start by adding brown or carbon-rich materials like shredded leaves and straw, then top with green materials like chopped fruit and vegetables, coffee grounds, eggshells, tea bags, grass clippings, etc. Next, add a layer of soil or compost to keep the cycle going.

2) Managing moisture-water well at least once a week but no more than twice a day. Keeping it wet will ensure that there are microbes present which break down the material faster.

3) Turning-when you turn your pile, you will help aerate it and again promote faster composting.

In the next part, we will be talking about the ratio considerations for composting for plants themselves.

What Is the Right Compost Ratio for Planting?

The ratio of compost to the soil is necessary for plant growth. It needs to be adjusted depending on the size of the plant.

The correct soil ratio to compost will depend on the type of plant, its size, and your garden’s needs.

For instance, if you have a large pot with just one or two plants, a better ratio might be four parts potting soil and two parts compost. If you have a large garden with many plants, then better ratios might be 1 part compost for every ten parts potting soil.

Composting tips and tricks you can use all around your garden

Compost is a beneficial thing! It provides nutrients and organic matter that plants need to grow.

Here are some ways you can use compost:

  • You can make your compost by combining organic materials such as leaves, grass clippings, food scraps, and coffee filters.
  • You can use it as mulch for your garden or potted plants to maintain moisture levels.
  • You can apply it directly to the soil around your plants to help break down the top layer of dirt and give your roots more access to nutrients.
  • You can even apply it directly to garden beds or lawns for use as fertilizer.

To sum up, everything in this article regarding making your own compost, you can check my recent article on composting for beginners. It covers video tutorials on what should and shouldn’t go into making compost, the considerations to their bins, contents, and finally, how to truly maximize the matured compost within your garden.

Conclusion about using too much compost for your plants

The right amount of compost is necessary for plants to grow. If it is too much, it will over-fertilize the soil and cause an excess of nitrogen, and be exposed to high amounts of producing high amounts of ammonia, methane, and other harmful gases.

This can lead to plant damage and many other problems, which is not what we want. Too much of it can also lead to an accumulation of ammonia gas and cause unpleasant odors near the compost pile or bin, so hopefully, the tips on how to avoid over composting your plants and garden up above can be a reference for you in your composting endeavor.

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Tony O'Neill

I am Tony O'Neill, A full-time firefighter, and professional gardener. I have spent most of my life gardening. From the age of 7 until the present day at 46. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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