Leaf litter in compost bag

Composting is a great way to create organic and nutrient-rich food for your garden but many people think that the process is complex and far too time-consuming. However, more and more gardeners are jumping on the ‘composing in builders bags’ wagon and are having some great results. Of course, as with anything, there is a knack for getting it right but it’s simple and almost anyone can do it.

In this short guide, we will be looking at how to start composting in a builders bag, even if you have no previous experience.

Why Should I Start Composting?

If you are new to composting, you might be wondering what the point of this process is. The great news is that there are a huge array of benefits to composting so even if you have stumbled upon this guide by chance, allow us the opportunity to tell you why composting is a worthwhile activity.

In the main, there are two reasons why composting is worth considering. In a world where being eco-friendly has more significance than ever, composting is an easy and viable way for gardeners to do their bit. Research has shown that, in the USA in 2018, only 4.1% of food waste was recycled; that is an astonishingly low figure and is similar in other countries around the globe.

By composting your food waste and other organic materials, it is believed that you could reduce your carbon footprint by a seriously impressive amount. In fact, composting for one year will save the equivalent of the number of harmful gases put out by your washing machine in three months.

Furthermore, your plants will thank you. Compost is one of the most natural and effective ways to feed your garden and when applied regularly, you should notice significant changes in the health of your plants.

Compost is incredibly rich in nutrients and this has several benefits for your garden including stabilising the soil’s pH balance, improving moisture and benefitting the soil structure.

What Does Compost Need?

If you want to get started on composting then there are a few key ingredients that will see you succeed. Without each of these things, the compost will not fully develop to its best, but using a builder’s bag will provide you with each of these things in just the right measures.

  • Air flow is essential to prevent the compost from smelling.
  • Compost needs heat in order to break down the organic material; some would say this was the engine of the process.
  • Moisture is needed to keep the compost hydrated.
  • Compost doesn’t develop overnight, this is a process that requires time.
  • Vegetation is required to keep the compost thriving.

How To Compost Using Builders Bags?

When most people think about composting, they imagine using a compost bin or large container. Perhaps you aren’t able to get your hands on one of these or would like to try something a little different. In that case, switching to a builder’s bag could be a great alternative.

These bags, which are used for transporting sand, soil, stones and other materials are the perfect shape and size and provide excellent conditions for your compost to develop. They won’t rot and are incredibly strong, so once you have your established compost bag, there’s a very limited worry about its durability over the long term.

Step One – Source Your Bag

If you are fortunate enough to have a builders bag lying around in the garden after a delivery of aggregates for your latest garden project, then you pretty much have everything you need. However, if you’re short of a builder’s bag, they are relatively easy to come by. You might try approaching your local builder and seeing if you can take a bag for a small cost.

Step Two – Finding The Right Location

One of the most important things to think about when starting to compost with a builders bag is where you will place your setup. In the main, provided that you place the bag somewhere level, you won’t have too many problems. However, you might also wish to consider the fact that these bags aren’t the most aesthetically pleasing and so hiding them in a garden work area or behind a fence can be a more preferable option.

If you are concerned about weeds underneath your builder’s bag then it is a good idea to place down some protective material such as a weed barrier. Regardless of where you place your builder’s bag, be sure to leave enough room to comfortably access it.

Step Three – What To Put Into Your Builders Bag Compost

Many people believe that, in order for compost to perfectly develop, there must be a balance of materials inside. However, this is not a correct assumption and while it is good to have a balance of materials, the most important thing is to ensure that you fill the bag. As soon as organic material becomes available, throw it in.

When you add materials, be sure to level out the compost and ensure that the materials fill each corner at the base of the bag. For the first few weeks, you will notice that the compost bag fills up very quickly. However, as materials at the bottom begin to degrade, the level will gradually drop, leaving you more room to add additional materials. You can put any of the following into your bag:

  • Grass clippings
  • Leaves
  • Rotten fruit
  • Vegetables or veg waste
  • Hedge trimmings that do not contain wood
  • Soft weeds

That being said, there are some products that should be avoided, these include bones or meat, wood, thorny plants such as roses, and perennial weeds.

Step Four – Maintaining Your Compost

Once you have everything in place, you will need to maintain your compost. When your bag is filling up, you will need to compact the materials as densely as possible. You can do this by either standing on it and using the bag’s handles to pull the sides up or you may simply use the back of a shovel to flatten the contents.

In any case, you will find that the bag quickly fills up and when no more can be added, you will need to cover it with a thick material such as an old piece of carpet and leave it alone for up to six months. It can be tempting to add more as the compost pile reduces down but it is important not to do this. If you want to keep composting, you can start a new bag.

Step Five -Using The Compost

Now that everything has nicely developed, you will be able to use your compost as mulch around your garden. Before adding it to the soil, it is important to give it a stir and check for any uncomposted materials. These can be added to a new bag and left for an additional few months.


Composting is an excellent way to add important nutrients to your garden and cut down on waste. While some of the commercially available composting bins can be quite costly, a builder’s bag is a great alternative. Getting started is simple and in as little as six months, you will have an ample supply of compost for which your garden will thank you.

Garden Doctor Trev

Garden Doctor Tips

“Remember that your compost will need a little moisture but do not over-soak!”

“Add anything organic and uncooked – veg peelings are a must and must not be thrown away!”

“Do not add perennial weeds to your compost, they may take root and start to grow again!”

“The beauty of composting is that it can be done anywhere and almost anything can be used to make it!”

Frequently Asked Questions

What is the process of composting?

Composting is a process that turns organic material into nutrient-rich soil. It can be done in the backyard, on a farm, or in an industrial facility. When composting, you take waste such as fruit and vegetable scraps and combine it with other materials like dead leaves and straw to create black gold-rich soil that helps plants grow!

What can you put in your compost bin?

What can you put in your compost bin? Well, there are quite a few things that can go into your compost bin. Think about all the fruits and vegetables that you throw away when they start to rot – those items are perfect for your compost bin! There is also grass clippings, leaves, eggshells… The list goes on and on. And what can’t you put in it? That’s an easy question – anything with meat or dairy products cannot be added to the compost pile.

What is bad about composting?

Composting is a great way to reuse organic material. But, there are some drawbacks that may not be so obvious. For example, you need a lot of space to compost properly and it can take several months before the compost is ready for use in your garden or flower beds.

About Me

Hi, I’m Trev and I’ve been growing things since I can remember. When I was younger, I grew up on a farm, so I have always been around plants and animals. After studying horticulture at university, I decided to start my own nursery which I have run now for 25 years. In my spare time, I run this website – which is a resource for people who want to learn more about their gardens.

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