If you’ve come across trench composting before, you might be wondering quite a few things about it – and the most significant question is likely to be “does trench composting work?”
The answer is yes, it does, but you need to do it right in order to get good results.
Trench composting can be a good alternative for people who can’t compost in heaps (or don’t want to) but still want to dig good nutrients into their garden and avoid sending organic waste to landfills.
Let’s look at trench composting, how it’s done, and how well it works.
What Is Trench Composting?
Trench composting involves digging a large area in your garden, and filling it with organic waste such as food scraps, garden clippings, cut grass, cardboard, etc.
It serves as another form of composting, where you don’t have to try to pile up and aerate the organic waste.
If you live somewhere with a lot of wildlife that might be attracted to compost heaps even if they are only full of raw food waste, or you are not allowed to compost in your area, trench composting is a great alternative.
It is particularly popular in the winter when the ground is barer and you’re more likely to have space for digging compost trenches.
Many people swear by this method of composting. It’s a great way to add nutrients to the soil without having to spread a lot of compost on or deal with a compost heap.
How Can I Start?
So, how do you begin to use the trench composting method?
First – unsurprisingly – you need to dig the trench. This should be around 60 or 70 centimeters deep.
You don’t want any animals to dig up your buried waste, so you want a deep enough hole to minimize the smell.
In terms of length, the trench can be as big as you want, according to the space limitations. You should aim for a reasonable length, or several trenches, to make this worth doing.
Next, fill your trench with organic waste. This can be grass cuttings, food waste, garden leaves, sticks, straw, paper, card, etc.
Don’t worry too much about ratios; this isn’t as important as in a normal compost heap.
You don’t need to fill your trench all at once. You can work your way along a little at a time.
Every time you put a new layer of food waste in, cover it with a bit of soil; this will discourage animals from grabbing it and spreading it about outside the trench.
When the trench is full, stop adding organic waste. Make sure it’s all well-covered, and then leave it to rot down over time. This soil will be great for planting in!
What Should I Do?
Add plenty of scraps to the soil; you want to give it a boost in nutrients, and you’ll do this by adding a good mixture of ingredients in quantity.
You can trench in rows between your veggies if you want to trench all year round.
Make sure you leave enough space for the trenches when planting vegetables (it may help to dig the trenches first), and then simply fill them and allow them to rot down over the course of the year.
This will provide your vegetables with valuable nutrients as the food waste breaks down. It can also help with moisture retention.
You may find you don’t have enough space to do this, so instead, you can try trench composting in the winter months (if you don’t use your vegetable garden for winter veg).
You can also try just trench composting on half if you do want to grow some winter vegetables.
When you empty your vegetable bed for the winter, dig some trenches, and fill them with food waste and garden leaves.
Cover them over and allow them to rot down in the winter months, and then plant directly into them in the spring.
The organic waste should help with moisture retention (ideal for vegetables) and also provide lots of nutrients for the coming year.
This is perfect for gardeners and saves you needing to transfer compost from a big heap to your vegetable garden.
What Shouldn’t I Do?
There are a few things to be aware of when it comes to trench composting, and avoiding these mistakes will make you more likely to be successful.
Don’t make your trenches very wide; you want the food to be able to break down and disperse into the soil, and it won’t do this quickly or effectively if you just dig a massive pit and pour in lots of waste.
Having wide trenches as well as long also makes it hard to fit them into your garden, and you may feel like the whole thing is just turning into a massive compost heap.
Keep them reasonably thin, and make several if you need more space.
Don’t add fish, meat, cooked food, or dairy. While these will decompose, they will smell much stronger than raw food waste, and may attract animals, which will dig them up and make a big mess in your garden.
You can try burying them deeper if you really need to get rid of these things, but it’s better to avoid it.
Don’t compact your food waste. You don’t want to be pressing it down, or packing the earth down on top of it.
Remember that compost works best when it is aerated, and while you won’t be turning your trench compost, it still needs oxygen to break down. Spread the soil on top, but don’t press it down much.
Do not add pet waste to your vegetable garden. This is very important as the waste from carnivorous pets can carry dangerous parasites and toxins, and trench composting does not get hot enough to kill them.
Compost pet waste separately or put it into your general waste; it doesn’t belong near your food.
What Are The Advantages?
Trench composting is considered an easy method that reduces the amount of time you have to spend spreading compost around in the garden.
It puts the nutrients directly into the soil, where you need them, and lets them break down slowly, without any further intervention from you.
It can help with moisture retention and ensures that plants are getting a regular boost. It also means you don’t have to spend time aerating and turning a compost heap.
Trench composting may be ideal if you dislike the smell of compost, or if you have neighbors who complain or your local area does not allow traditional composting.
It can be a good way to return nutrients to your soil without the disadvantages associated with compost bins.
What Are The Potential Drawbacks?
Trench composting isn’t perfect, of course. It can cause a big mess if you don’t get your trench deep enough and an animal decides to dig up your food waste and spread it all over the garden.
It can also look a bit messy. While traditional compost heaps aren’t pretty either, they can be kept relatively tidy, especially if you have a bin.
Once the trenches are filled, they will look fine, but while you’re filling them, you might feel they’re a little bit of an eyesore, especially if you have several.
This may not matter to you if you’re doing vegetable gardening, but might not be ideal in an ornamental bed.
They also involve small amounts of regular work. Every time you add compost, you will need to grab a shovel and cover it.
This isn’t a big deal for most people, but it’s a consistent chore that will have to be done every time you add compost.
The constant maintenance required by trench composting may put you off.
A small-scale version of trench composting is called dig and drop, and you may find that this suits you if trench composting doesn’t.
It involves digging small holes in the garden and following the same method of burying food waste so that it decomposes underground.
Dig and drop may be more suitable for fertilizing ornamental beds, or for composting if you don’t have large, unused spaces.
You can use the two methods in combination with each other very effectively.
Essentially, dig and drop gardening is the same method scaled-down, so if you find you want to compost food somewhere that you don’t have space for a trench, just dig a little hole instead.
You can use this in your vegetable plot to fertilize certain crops, or anywhere in your garden.
Trench composting is a great method for many people to use.
It is a particularly good way to get nutrients back into your vegetable garden in the winter and dispose of food and garden waste if you aren’t allowed to use a traditional composter, or if you don’t want to.
It has some potential drawbacks, but it is becoming increasingly popular with gardeners, and one of the great things about it is that it’s easy to try out.
If the method doesn’t suit you, you can just choose something else and move on!