Some new gardeners and composters confuse compost with fertilizers. They aren’t the same. They serve some of the same values but they also each have their own benefits and disadvantages. In this article, we’ll discuss compost vs. fertilizer, what they do, their benefits, and their disadvantages.
Compost is created by the decomposition of natural materials into their core nutrients. You can add it to the soil to enrich the soil. It improves the nutrient value of the soil and improves the characteristics of the soil to make it better for growing plants.
Fertilizer provides nutrients to the plants themselves. Different fertilizers have different mixes of nutrients depending on the needs of the plants.
Basically, in simplest terms, when you think of compost vs. fertilizer, think of soil versus plants. Compost feeds the soil, and fertilizer feeds the plants. Of course, healthier soil leads to healthier plants, but they do serve different purposes. The soil benefits from compost mean that one of its many benefits is that it reduces the need for fertilizer, but it may not eliminate it.
Composting
Composting is produced from decomposed organic material, which is a mixture of nitrogen-rich material (greens) and carbon-rich material (browns), among other nutrients. It’s created by taking advantage of natural processes where microbes, worms, and insects help the material decompose in a pile, bin, tumbler, or other structure.
There are a variety of different types of composting, which can be done both at home or on an industrial scale. It’s a natural process. Compost is mixed with the soil directly or through a compost tea, where compost is steeped in water for a while, and the resulting solution is added to the soil. It’s the ultimate Circle of Life demonstration.
The benefits of compost vs. fertilizer are many, but it has some drawbacks as well.
Pros of Compost vs. Fertilizers
Nutrient Rich Soil
The decomposition of plants, brown material, and the rest of your compost leads to very nutrient-rich soil, which is a better growing medium for your flowers, grass, and garden.
Disease Resistance
Compost improves the nutrients in the soil and reduces the risk of disease to the plants.
Improved Water Retention
Soil with compost added tends to hold on to water better, and it reduces rainwater runoff. This has several benefits all on its own.
- Reduced watering needs – Compost can reduce irrigation needs by 3-10% per year.
- Improved soil moisture
- Reduced fertilizer runoff, allowing you to make better use of fertilizer that you do add
These protections come for the fibrous material that is left over after the composting process, called humus. It helps to absorb and block water run-off.
Cons of Composting vs. Fertilizers
Of course, nothing is perfect, and compost is no exception. Here are some of the things to consider as you look at your options and the best strategy for you.
Time – It Takes a While if You’re Making Your Own
Composting is not a fast process. It often takes months to make it on your own. It’s fun and a great way to reduce your own personal environmental footprint. It takes a while, though.
Of course, you can buy compost while you wait for your compost. Often, it can be purchased at any garden store or at a commercial composter if you have one locally.
Time is probably the biggest disadvantage of composting.
Can Be Difficult to Get Enough on Your Own
It can take quite a bit of compost to fully improve the soil, especially if you have a big garden. You might need more waste than your own house can create. You might also need more space for a compost pile that big.
With a moderate garden, we saw a big difference in even one year, and a small amount of compost was made into compost tea, so there are solutions. You may not get all of the benefits, though.
Compost Pile Can Smell
Normally, compost shouldn’t smell, but if you don’t quite have it right, it can definitely smell up your yard while you figure out how to fix your imbalance.
Personal Work
Composting at home isn’t hard, but it does take some effort. If you’re already busy, it’s another thing to do. Of course, we feel it’s worth it, but not everyone agrees.
Space
If you have a small yard or live in an apartment, outdoor composting may not be an option. Indoor composting is an option almost anywhere, but it may be difficult to get a big enough volume through indoor composting.
Fertilizer
Fertilizer is any of many natural and synthetic substances that can be spread onto or into the soil to support the growth of healthy plants.
Fertilizer provides nutrients to the plants directly. Fertilizer is typically some sort of chemical or natural nutrient supplement that you apply on or around the plant. Therefore, there are opportunities to target the fertilizer directly to the plant’s needs.
Fertilizer is rated by its “NPK” rating, which is an indication of its levels of nitrogen, phosphorous, and potassium. (K is the chemical symbol for potassium.) These are three of the key nutrients that plants need, so fertilizer is rated based on how much of each it provides. The ratings are three numbers that represent the percentage of each of these macronutrients that it provides. It’s a bit like the nutrition labels that we see on food.
Pros of Fertilizer vs. Compost
Adds Nutrients and Can Be Targeted to the Plant
Fertilizers add nutrients directly to the plants. This means that you can target the fertilizer directly to the particular type of plant, its needs, and what may be missing from the plant or soil. Therefore, fertilizers can be more specific than compost.
Immediate
Fertilizers are more immediate. You don’t need to wait for the plant to take the nutrients that it needs from the soil or for the fertilizer to be made as you do home composting.
Cons of Fertilizer vs. Compost
Can Overload with Nutrients
Particularly if you aren’t an expert, you can add too many nutrients or too much of a particular nutrient to the plant or plants. This is often a case of too much of a good thing.
Fertilizers often break down at different rates. Particularly if you are mixing fertilizers, it can be difficult to properly measure the nutrients.
Too much can harm the plants, surrounding plants, the soil, or your garden as a whole. This causes a “burning” of your plants where the roots are damaged or dried out.
Environmental Impact
The other problem from nutrient overload is that the nutrients not used then run off into the groundwater. It often flows into the larger water system into rivers, lakes, and oceans, feeding algae and other aquatic plant life. This plant life often strangles other parts of the ecosystem, and it can cause immense harm to the ecosystem and even make people sick from the impact on the groundwater.
Too much fertilizer can have several environmental impacts. While a little home garden alone doesn’t cause these issues, it does contribute.
Fertilizer has been linked to:
- Algae Blooms, such as those seen in Florida’s Red Tide
- Depletion of Oxygen in Surface Water, which can impact wildlife
- Pathogens and Nitrates in Drinking Water
- Odors and Gases Being Released Into the
Our small garden doesn’t create red tide, but enough of fertilizer washing into the water system does.
Can Upset The Balance of Natural Microbes
There are microbes in the soil that help the natural balance of your plants. They help to ensure soil and plant health. Fertilizers can harm these microbes, which can ultimately cause harm to your soil or plants.
Do You Need Fertilizer if You Use Compost?
For a home garden or your lawn, you may not need fertilizer if you use compost. Often, the improved nutrients of compost is enough benefit for your plants. Commercial planters will often need both. You might as well if you’re not getting enough benefit from your compost.
Often, you may need to use both fertilizers and compost.
Can You Use Compost and Fertilizer Together?
Not only can you, you probably should. Compost is completely natural and has many benefits. It helps the nutrition of your soil and helps to retain moisture.
The good news from this is that you can use less fertilizer and may be able to avoid some of the harsher chemical fertilizers altogether. Fertilizers can be great for plant health, but they have some serious side effects. They lead to environmental impact and can even harm your plants if not done right.
Compost and fertilizer server different functions. You can use them together and would be better off than using fertilizers alone. For many home applications, you might be able to avoid fertilizers altogether if you use compost.
Compost vs. Fertilizer
Compost and fertilizers serve different functions. Compost feeds the soil and fertilizers feed the plants. Compost is completely natural. Fertilizer is often made from various chemicals or additives.
Each of them has their role. Compost can help you use less fertilizer with less environmental impact. Fertilizer provides targeted nutrients to your plants. Knowing how each of them works can help you decide what to use when.