Tony O’Neill, gardener and author of the popular “Composting Masterclass” and “Your First Vegetable Garden,” combines lifelong passion and expert knowledge to simplify the art of gardening. His mission? Helping you cultivate a thriving garden. More on Tony O’Neill
Towards the end of the growing season, a gardener’s biggest dilemma is what to do with the spent, used, or old compost. And while gardening can itself be quite expensive, it is important to find certain ways in which you can save time, money, and resources. But how can one make the most of their used compost?
There are a number of ways to reuse compost. You can either use it as mulch or level your ground. You may even make new compost out of it or feed container plants with it.
So, the next time you are left with loads of compost, you should consider using it over again. Here we also curated 8 amazing ways in which you can reuse your used compost and make the most out of the compost that you have access to:
1. Use Old Or Spent Compost As Mulch
Mulching has several benefits, such as maintaining the moisture level of soil. It also gradually releases nutrients to your plants, preventing soil erosion, suppressing weeds, and removing the residual effects of fertilizers or pesticides. Used compost makes a fantastic mulch.
And you can use your old compost as mulch in an easy way. Simply spread it on top of your vegetable or flower beds. Since compost is naturally quite dense and absorbent, it will prevent evaporation and thus lock moisture in.
Just apply a generous amount of compost around a 3-to-6-inch layer, and rake until the ground is even. This would be an amazing way to boost your soil, especially if you have sandy or clay soil in your garden.
But other than this, the compost will eventually mix with the soil, feed the worms and soil life, and make a whole new rich compost for your plants.
2. Add Finished Compost to Level Your Garden
Another amazing way to reuse compost is by leveling your garden. This can help you even out a slope in your garden you do not need. You may even use it to fill up some raised beds. Add generous amounts to the soil to help build microbial activity and build soil structure.
This will allow the compost to get into the roots, enhancing the nutrients of the soil and thus promoting plant growth. Not to mention, leveling the ground can offer many benefits like proper water coverage and better drainage.
3. Add Used Compost to a New Compost Pile To Improve Soil
Using spent compost as an ingredient to create a new batch is a great way to recycle resources and develop something valuable for your garden. You can easily make new potting soil or compost from your used compost. Begin with removing large debris with the help of a half-to-1-inch soil screen or sieve.
Layer old and new compost alternatively. With this, the new compost can rot into the old one while adding goodness and nutrients. So, your used compost will be rejuvenated in no time, and you will double the amount of workable compost in your garden.
One of the most important things to consider while layering is that you do not want to pack them too tightly. Try to keep thin layers, which will make air circulation much easier. Adding worms can also help in creating pathways and allowing better air penetration. They also have a bunch of other benefits. So, if you can, add as many as possible.
Once you are done, do not forget to cover your compost heap with a waterproof sheet. Add a plastic sheet to prevent the compost from damping during the rainy season. The cover will also trap the heat inside and accelerate the process, ensuring your compost is ready sooner.
Here is a list of things that you can add to your compost to make it a lot more beneficial and nutrient-packed:
- vegetable peelings
- grass clippings
- tea bags or coffee grounds
- hair clippings (human or pet)
- newspaper or paper (uncolored and natural)
- wood shavings
4. Use Spent Compost to Brew Compost Tea
Compost tea is basically a brewed liquid that concentrates bacteria, protozoa, and fungi into a liquid form that can be easily absorbed by the soil. There are majorly two types – compost tea and aerated compost tea.
While the latter requires oxygen, agitation, and a little more effort, it can be a good option as it is not as smelly. Both these types only take about 24-36 hours to make and are perfect for increasing the biological activity in your soil.
Compost tea is believed to improve soil quality and the number of mycorrhizal fungi and predatory nematodes that reduce the risk of disease in plants. So, using your spent compost to brew some compost tea can be a great idea, given that your plants can soak up it easily and extract various nutrients from it.
5. Use Leftover Compost for Growing Carrots or Leafy Greens
As a gardener, you would know that certain plants need fewer fertilizers and nutrients to thrive as compared to others. Usually, leafy greens such as spinach, lettuce, and bok choy fall under this category.
So, if you have a lot of finished compost, growing these plants can help you use them up. Other than this, you can consider growing carrots as they also require a lesser amount of nutrients.
In some cases, old compost can even help you produce better-quality carrots. Excessive nutrients may result in smaller fruit sizes and more foliage rather than bigger carrots and lesser foliage. With limited nutrients, you can also decrease the risk of root forking. A win-win situation!
Adding it to your soil can really help improve the structure without increasing the fertility if you already have sufficient amounts.
6. Use Finished Compost to Fill Raised Beds
Plants tend to do better in raised beds as they offer better drainage and warm-up earlier during spring. Moreover, the soil is less compacted in raised beds making air penetration better. Also, if you have been planning on building raised beds, this is probably a great time to do so.
One of the best ways to reuse compost is by filling raised beds with it and building an ideal plant-growing environment. You can dig it into the soil in the bed or spread compost over the beds after clearing the ground. Now, you only need to wait and let the worms do their job.
7. Reuse Old Compost as Top Dressing
Another way to use your finished compost is to mix it with plant food and top-dress your planters with it. Compost is known to dry quickly, so mixing it up with soil is also a great way to ensure balanced bedding for your flowers and plants.
This would work even better with your perennial plants, keeping them healthy and blooming. You can also consider compost as a top dressing for your perennial plants each year.
For better results during the spring season, spread it over (one to two-inch layer) during fall. Adding it to the soil surface also aids in keeping down weeds.
This will last much longer and offer a continuous source of food to your plants. You can even spread it across the lawn and rake it until it is slightly visible. It will soon be taken down by worms, ground beetles, and other organisms, which will help improve the soil’s texture and quality.
To understand better how to reuse leftover compost, you can watch the video below:
Inoculating The Compost as a Guardian
Compost inoculation is adding bacteria that help start the population growth and speed up the composting process.
This is known to improve the quality of the compost to a significant level. If all requirements are met properly, 1 bacterium can multiply into 8 billion bacteria in just 13 hours. All you need to do is mix it with water and let it activate, then add it to the soil.
Frequently Asked Questions
What is the difference between soil and compost?
One of the easiest ways to understand the difference between soil and compost is to remember that compost is used to feed the soil. Compost is decayed organic matter that is worked into the soil and acts as a nutritional booster. Compost can be made up of fruits and vegetable scraps, animal manure, and kitchen waste.
How to know if my compost is old?
When you cannot recognize your compost’s food or garden waste, you will know that your compost is spent. It should look similar to dark, nutrient-rich, and healthy garden soil. I wrote a blog to help you know how long it takes for compost to decompose. You can read it here.
How to know if used compost is ready to be reused?
Usually, used compost can be used over and over again. But in certain cases where your plants have observed diseases such as onion white rot, you should probably consider dumping the leftover compost as it may also infect your plants in the next growing cycle. However, if you are sure that your compost is still healthy and needs to be rejuvenated, you should make the most out of it. Also, remove any slugs or snails from the compost before reusing it.
How to prepare my old compost for reuse?
To prepare your dead compost for reuse, remove all the old plants and weeds from it. Trying to dig in to find old plant rootstock as well. This may even help you find eggs of pathogens or insects (like vine weevils or flies) that may lead to disease. Once, the compost is free from all debris, it is ready to be used again.
How many times can I reuse old compost?
It majorly depends on your judgment. If you think your old compost can still be used, go ahead. However, it is important to pay close attention to the quality of the compost and soil. Compost loses its nutrients with time, so adding and using new compost is better. Eventually, you will notice that your soil needs to be rebuilt to gain its structure and quality back.
I hope that with this, you can make the most of your used compost and save time, effort, and resources.
I am sure that at least one of these amazing ways of reusing old compost will prove to be helpful to you and will also bring value to your garden.
After all, gardening is all about investing your time and reusing resources to build and maintain a healthy environment where your crops can flourish in a healthy and eco-friendly way.