Can Compost Be Too Old To Use? (What You Must Know)


Gardening can be a fun and interesting hobby, whether you buy or make your compost for growing your favorite crops. Are you concerned whether your compost might be too old to plant in?

Because of all the ingredients in compost, it can go bad. Bagged and readily purchased compost in bags can degrade, start to smell, and lose nutritional value if allowed to sit for too long. Compost piles, largely consisting of composted organic matter, will not go bad unless you store it improperly.

If you are worried about your compost, do not fear! There is a lot to learn from knowing whether your compost is old and how to improve its overall quality!

How To Know Your Compost Is Old 

Knowing when your compost is old and struggling will give you enough time to rejuvenate its nutrients in time for when you want to plant your favorite crops. Below is a list to help you to know when your compost has become unusable for crops:

  • The compost pile is moist, but the material is matted and takes longer to break down.

This means that your compost pile has a difficult time breathing. Two types of microorganisms break down organic matter: those that need a high volume and quality of air (the aerobic) and those who need a lower volume of air (the anaerobic). For optimal composting, you will want to encourage the faster type of aerobic life forms.

  • Your compost pile smells very bad.

Foul and unpleasant smells are usually a good and accurate indicator that your compost pile has become too wet and has gone anaerobic.

Several factors can contribute to this condition, like the lack of aeration, giving too much water, or an imbalance of carbon to nitrogen. Without the correct amount of air, the materials will become stagnant and rancid.

  • Brown leaf material added the previous year is still not breaking down.

Brown and green balance is a blanket term used to describe the ratio of two necessary elements needed in the process of decomposition. These two elements are known as carbon and nitrogen. Microbes prefer a carbon to nitrogen ratio of 30:1 to do their best work. The “browns” (or carbons) include materials like leaves, straw, dry grasses, sawdust, or pine needles.

The greens consist of nitrogen-rich materials like kitchen waste, manure, or grass clippings. When it happens that your ratio is slightly off, your material will still be able to decompose, but if you want the products to decompose quickly, you will have to be as correct with the ratio as you possibly can.

  • Your compost caught fire.

Though it is quite common to have an excess amount of browns in your compost, there is a negative result in adding too many greens. Excessive amounts of nitrogen will cause your compost pile to heat up very quickly and combust, which becomes an obvious fire risk.

You will be relieved to hear that compost fires are luckily extremely rare. Compost fires are more likely to happen in industrial-sized compost piles. However, your pile may still get too hot, and that leads to the problem of burning and killing your plants if you do not allow your pile to cool down for a period.

  • There are no bugs or worms visible in the compost pile.

A healthy compost pile should have colonies of worms, mites, and other types of living organisms whenever you turn it over with a pitchfork. If your compost is old and worn out, you will definitely have no signs of life present, as living organisms are after nutrients in the compost.

  • Sticks are struggling to break down or not breaking down at all.

Taking the term “micro” into consideration, it refers to the animals doing the job in your compost, which are tiny living creatures who take small bites of your compost. When you add large sticks and twigs to your compost pile, it will greatly impact the speed at which these organisms can break them down.

 It slows down the decomposing process, and larger chunks cannot hold the moisture capacity to provide the necessary water balance in your compost pile.

  • You’re not making enough effort!

We all struggle when it comes to finding ways to manage our time. Adding composting into your maintenance schedule can feel like it takes up a lot of your time, but it doesn’t have to be intensive to be effective. 

Checking up and tilling your pile regularly can save time for the future, and it will benefit you, as you will struggle more with old compost than compost that has been taken care of correctly!

To Use Old Compost Or Not To Use?

Many gardeners usually want to start repotting their plants before bringing them indoors or into the greenhouse for the winter. As a result, they may have a growing pile of used-up compost, leaving them to choose to reuse it or chuck it away. Could old compost be reused to save money, resources and time?

The answer to this is yes! Many people take up gardening as a hobby or activity to help them save money and reduce waste. After all, it is a wonderful idea because when you grow your own fruits and vegetables, you’re effectively cutting down on packaging. Even if you have your own compost bins at home, you may still want to reuse the compost you have already worked into your containers for zero wastage!

The overall process of composting is relatively easy,  but it does require a certain adherence to a 60/40 formula of both green and brown materials. If you neglect your compost, it could fail to break down, lose its nutrients and even get moldy. 

Reviving your old compost pile for the usage of new crops will take an amount of effort, but it can result in good material for use in your garden. As the colder days of winter gradually come to an end, you may start to wonder if your compost is dead. 

As stated, compost can certainly get old, and you can recognize old compost simply by looking at its appearance. Old compost has a distinct gray color, is usually very dry, and has no sign of organisms like pillbugs and earthworms.

How To Improve Your Old Compost (And How)

Rejuvenating your old compost is not a precise recipe but can be seen as trial and error. Don’t let this put you off. Experiment, learn, and observe the results, and you will soon know what works for you. It might be more difficult to get extraordinary growth out of old compost, but there are several materials you can add to your old compost to get the best results out of it!

  1. Worm compost

Worm compost is the urban container gardener’s best option! Worms are one of the most beneficial “ingredients” you can use to rejuvenate your old compost. Worm compost is usually rich in all the major nutrients and will bring life back into your compost. You can even start your own wormery if you have space for one!

How to use it:

Add between 10% of worm compost if you plan on growing salads and up to 50% for squash or tomatoes to your old compost. It would be best to be careful not to add too much, as it could be extremely rich.

 You could add a layer on top of your compost later if you think you didn’t add enough! If you have a few containers that need rejuvenating, you can remove the old compost into one big container to mix it all.

  1. Bokashi

Bokashi is known as a Japanese method of composting. It uses EM (Effective Microorganisms) and needs much less space than a wormery. You will only need a bucket for the Bokashi method of composting, and it is much faster than the other composting methods. 

Taking only about two weeks, you can use this method for inside and outside gardening, and it could be a good alternative to a wormery if you aren’t fond of worms!

How to use it:

The end product you can expect when using the Bokashi method of composting is partly composed of pickled vegetables. You can use this compost almost identical as you would use worm compost, but it is less versatile. 

This is because of what comes out of the bin. Your compost bin will not be full with a finished product, and your vegetables should be left in your soil for a few weeks to be able to settle before you can start growing in it. 

You can mix 10% to 30% pickled bokashi vegetables into a container, or you could add them to the bottom of your pots before filling them with your old compost. As the added picked vegetables break down, they will release all its containing nutrients and add lots of beneficial soil life to your rejuvenated compost.

  1. Manure

Manure is another of the most useful ingredients in reinvigorating used or old compost, especially if you cannot make your own worm compost! Manure teams up with soil life which is highly beneficial to all growing crops. Manure also has most of the essential nutritional sources that plants need in moderate quantities. Manure does, however, vary in quality.

 To use manure safely in your old compost, you will need to check a few things. The first thing you should always check is if the manure is well rotted. If the manure is ready to be used, it should smell more like a common garden soil than animal feces.

 Secondly, it would be best if the manure you have decided to use hasn’t come from animals farmed inorganically or fed antibiotics. Using the “cleanest” manure possible, you will undoubtedly get the best and highest quality crops out of your rejuvenated compost.

How to use it:

You can mix your well-rotted manure into your old compost or just put a layer at the bottom of your pots. Adding manure at the bottom of your pots will work best when using bigger bots, or you could add a layer to the tops of your pots halfway through the season. Gardeners call this “mulching,” which is beneficial to crops like squash that need many nutrients.

 If you are unsure how to tell if your manure is rotted enough, you could either leave it in a plastic bag for a few weeks or directly put it in the bottom of a big pot where it can slowly break down. Depending on your manure and the growing crops, you can add between 15% and 50% to your old compost to fully rejuvenate it.

  1. Manure pellets

Manure pellets contain all the different main nutrients that your crops will need and are particularly high in nitrogen. Because your plants need nitrogen for absolute leaf growth, manure pellets are excellent to rejuvenate the old compost that you want to grow leafy vegetables like salads or kale in. 

How to use it:

Use your manure pellets in moderation for fruiting crops like beans or tomatoes. If you add too much, you will get very leafy plants without many fruits! You should always follow the guidelines provided on the packaging when using manure pellets. 

  1. Green waste compost

More cities worldwide collect household green waste, such as grass clippings and prunings, and then convert it into compost. The compost is often then sold back to the general public, and sometimes food waste is added as well. 

The resulting compost can widely vary in quality, but the quality is usually excellent. If you find a supplier, this type of compost will benefit your older and depleted compost tremendously! 

This is because green waste compost is fairly rich in nutrients, and it is exactly what you want when rejuvenating old compost. It also typically contains quite large particles. The larger particles could be sieved out, or you can leave them in, as they will help add structure and air gaps back into your compost.

How to use it:

Mix 15% to 50% into your old compost, depending on how rich a mix you want to make. You can also add a layer to the top of your containers, and the nutrients will slowly work their way into your compost to rejuvenate it. 

The only catch with green composting is that it could be relatively low in soil life, so for the best results, it would benefit you to add something like worm compost or manure if possible.

  1. General-purpose organic fertilizer

If you are struggling with space or simply want to go and buy yourself fertilizer to mix in with your old compost, you can rest assured, knowing it will work just as well! Store-bought fertilizer can be very useful, especially if you do not have a supply of the ingredients mentioned above. 

And, even if you do have the ingredients, bought fertilizer can be useful to raise the nutrient levels of old compost. When reusing old compost, you will want a balanced fertilizer. 

If you are unsure whether fertilizer is balanced, look for the “NPK” details on the side of the packaging. If the numbers are roughly equal for NPK, like 5:5:5, it will work perfectly, as long as the numbers are below 8.

A common general purpose fertilizer is “blood, fish, and bone.” There are vegan equivalents too, but they might not be as readily available.

How to use it:

Always mix your fertilizer with your old compost before you decide to do any form of planting. The fertilizer will always come with guidelines on how much to add. You can use the guidelines as a starting point and then observe the results.

 You can add more or less each time, finding what works best for you and the compost quantities that need to be rejuvenated. You can also add sprinkles of fertilizer to the top of your old compost after mixing the first batch of fertilizer to top up the nutrients as your plants grow.

Conclusion

Although we are focused on growing the best crops we can as gardeners, we tend to forget that the nutrients we provide them with are equally as important. Getting your compost pile going again after a long and cold winter can sound intimidating, but it is possible with a little time, love and effort!

For having a successful compost pile, assess your starting point, manage your inputs, and you will be turning your hot pile in no time. The first step for rejuvenating old compost to make it useful again would be to monitor your pile. When it is dry, water it and turn it at least once a week. If you follow these steps, your compost pile should be healthy and working in no time!

If you tend to only refill your pots with fresh soil and compost each year but still want to reuse your old compost somewhere, you can always use it in your garden. Your garden crops will appreciate the new ad improved compost, and it will still pump nutrients back into your soil.

.

Resources

https://www.theguardian.com/lifeandstyle/2019/may/18/how-to-reuse-old-compost-alys-fowler

https://davesgarden.com/guides/articles/can-you-reuse-spent-compost

https://www.gardeningknowhow.com/composting/basics/reviving-old-compost.htm

https://blog.soil3.com/can-compost-go-bad

https://verticalveg.org.uk/how-to-re-use-old-compost-ten-useful-ingredients/

https://extension.illinois.edu/global/news-events

Recent Posts