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The Hidden Benefits of Reusing Old Compost (Your Plants Will Thank You!)

The Hidden Benefits of Reusing Old Compost (Your Plants Will Thank You!)

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Many gardeners spend a significant amount of money each year on buying large bags of compost.

Compost is needed for a variety of reasons, ranging from hanging baskets to pots. It is also used for growing specific kinds of plants such as tomatoes and cucumbers. If you have a greenhouse, you most definitely have a big bag of compost in your house.

You might not realize this at first, but instead of throwing away the old compost, you can easily use it in a variety of different ways. You might have read many books that tell you that using old compost is a bad idea, but you have to understand that these books simply assume that you have the money to buy an unlimited supply of compost.

In some cases, you should avoid using the old compost. For instance, if your plants died because of a soil pest or a problem such as a vine weevil, it might not be a suitable idea to use the compost again.

However, if the plant just looks a bit tired, you should consider using mulch on it.

Even if you have just a few pots handy, you can easily refill them with old compost and use them. But, the question remains: can you use old compost?

The answer is a resounding yes. In fact, when you prepare the old compost properly, it can easily last you several seasons, and in some cases, it can also last you indefinitely.

What You Need to Know

While there are quite a few variables and factors that you need to consider, it is important to understand a few things.

First and foremost, you need to know that there are some crops that are much easier to grow in old compost as compared to others. Another thing that you need to know is that after a season of plant growth, most of the nutrients found in the soil will have been used up.

To reuse the soil properly, you will have to replenish the nutrients found in the soil. It is also important to understand that the structure that is used for the growing mix is going to break down over the passage of time.

To ensure that your plants grow in a healthy manner, you will have to add a few things after a year or so. This is important for “rebuilding” the structure.

Again, it depends on the medium; certain medium types retain their structure in a better way than others.

Which Crops Can Be Grown in Old Soil?

While it is entirely possible to grow various kinds of crops in the older soil, you should know that some will grow faster and require much less maintenance than others. That’s because certain crops have very specific requirements. Others, on the other hand, do not create a big fuss.

Some of the crops that you can easily grow in old compost include leafy vegetables such as salads, rocket, kale, lettuce, and chards. Most root vegetables are also going to grow easily in the old compost.

Apart from that, you can also plant peas and beans and expect them to grow without much of an issue. Squash and courgettes, such as zucchini will also grow. Most types of herbs can also grow in the old compost without requiring much of an effort.

The crops that you will have difficulty with include tomatoes, most types of aubergines, strawberries, pepper, and chilies.

Keep in mind that crop rotation is also necessary. You have to understand that rotation is not that important in containers as it is in the ground.

Ideally, it would be a wise move on your part to avoid growing the same crop in the same soil for more than one year. There are several reasons for this. The most obvious reason is that it is going to prevent pests from building up in the soil.

Furthermore, it’s also going to prevent the excessive consumption of nutrients that are found in the soil.

What Can You Do with Old and Spent Compost?

There are several things that you can do with old and spent compost. For starters, you can mix and create new compost with it. Just mixing it with potting soil is a great way to increase the amount of compost available to you.

Secondly, you should know that old and used compost can also be used as mulch.

Mulch can be spread on top of your vegetable and flower beds, and it can play an important role in moisture retention in the soil. Not only will this improve the soil by a significant margin, but the mulch will mix with the soil on its own, improving the amount of nutrients in the soil.

You can use the old and spent compost to evenly grade and level out your garden as well. If there are big dents or holes in your garden, you can use the old compost to level it out properly. Sloping gardens can be graded and levelled easily using old compost.

Furthermore, you can also use the old compost to create a bottom layer. You can use the old compost to partially fill the bottom of deep containers or plant pots.

This will reduce the amount of fresh compost that you have to use. For plants that do not need a considerably high amount of compost, this is a great way to save both time and money.

Conversely, you can also use the old compost as a top layer of soil as well. You can easily spread it over the lawns and then use a conventional garden rake to spread it all over your garden.

Make sure that you do a fine job so that the top layer is barely visible. The worms are going to do the rest; they are going to take the top layer all the way down to the soil.

Compost can also be used for growing carrots in your garden. The next year, you can use the old and spent compost to grow carrots in your garden.

Carrots hardly require any nutrients to grow, so the old compost is actually much better for the roots to take hold.

If you provide an influx of nutrients for the compost, the size of the carrots is going to reduce, and the amount of foliage will increase.

If you want larger carrots in your garden with a smaller amount of foliage, you should consider using the old compost. This will also prevent the risk of the roots forking as well.

If you have cows or horses or live on a farm, the old and spent compost can be used for bedding for the animals on the farm as well. Horses and cows are especially going to love this, and you can later add manure to the whole mixture.

Filling up Holes

Are you tired of the holes left by animals such as hedgehogs or moles in your garden? The old compost or potting soil can actually come in quite handy for getting rid of these holes and creating an even layer around the garden without compromising on the nutrient quantity of the soil.

Animals such as dogs, and many tiny critters also create uneven holes throughout the garden. These need to be patched and filled out on a regular basis, and the best way to do that is by using the old compost soil. You can put in the grass seeds and then cover them up with the compost.

If you are going to pot up some giveaway plants, you can also use the compost. You can just put in the divisions of other plants and then use the old compost to properly store them.

It’s a great and inexpensive way of creating giveaway potted plants. You can also use these plants in your own garden or greenhouse.

Most gardeners generally prefer mixing the new soil with the old one, usually mixing them in a proportionate manner. By adding a small amount of organic fertilizer, you will be able to replenish the amount of organic nutrients in the soil.

This is going to boost the nutrition for the plants.


You should know that old compost actually works incredibly well as compost for your flower beds or your vegetable garden.

Not only does it increase the amount of organic matter in the soil, but it also helps in preventing the moisture from evaporating. If you want to conserve water and don’t want to buy bags of mulch, you should definitely consider using the old compost as mulch.

One of the main reasons why you should consider using old compost is because it will help in keeping the weeds down in your garden. Weeds can spread quite quickly throughout your garden and you are going to have a hard time getting rid of them.

Since most people don’t get the time to work on their garden, taking preemptive measures is the way to go.

By spreading out the mulch all over your garden, you will be able to reduce the occurrence of weeds by a considerable margin.

But, before you decide to spread the mulch all over your garden, it is important that you smell and check it. If the compost seems smelly or has a slimy texture to it, you will want to avoid using it.

Instead, it might be a wise idea to mix the compost in the bin and then use harder materials to mix the compost properly. Straw or shredded cardboard are both suitable materials that you can use to mix the compost properly.

This will allow the compost to regain its original texture and will also allow it to regain the natural balance.

It will start smelling the way it used to, and will be ready for use in the garden.

Keep in mind that rejuvenating the old compost is definitely not an exact science. There are a variety of factors that come into play, such as the age of the compost, the amount of nutrients that are found within, as well as the amount of compost that you are mixing.

This is more trial and error at best, but that’s not a reason why you should be put off. It’s best to experiment with the old compost, and you will be able to observe the results.

Of course, it is going to take a bit of time for you to understand how it works, and once you know, it will become much easier for you to mix the old compost with the new together.

Keep it Light

One of the most important things that you should know about mixing old compost is that you have to keep it light.

It is important that there is air between the layers when mixing the compost, otherwise it’s going to become compacted. Try to keep the layers as thin as possible so that the plants and the root are able to breathe.

Otherwise, small things such as the grass clippings are quickly going to turn into a disgusting layer of slime. Air needs to be able to penetrate the pile so that this doesn’t happen.

You have to be a bit careful when mixing the compost together. As mentioned, it is going to take you a bit of time to mix the compost properly.

It’s going to require a few tries for you to be able to mix the soil properly. Another thing that you can do is mix as many worms in the soil as possible.

Mixing the worms is important because it will allow you to spread the material throughout the pile. The worms are going to mix the materials together and they will make it easy for the nutrients to spread out all over the pile.

These are just a few of the many different ways in which used compost can be used around the house. Make sure you practice!


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