Compost bins are great but have you ever considered in-ground composting? There’s no bin needed and you never have to turn it. In fact, once you put the scraps to work, you don’t even have to think about them again!
Getting started in composting can seem a little overwhelming but it doesn’t have to. In it’s simplest terms, composting is simply allowing organic material to decompose and return to its more fundamental form. Yes, you can speed up the process dramatically by regularly turning your compost in bins or using tumblers. For active gardeners who are needing compost quickly, this is a great approach.
But if you aren’t ready to dig into the science of carbon-nitrogen ratios or you just aren’t keen on the idea of having to actively maintain a compost pile, there are other ways for you to start composting your kitchen scraps. Best of all, you can get started today with some of these using nothing more than a shovel.
How In-Ground Composting Works
In-ground, or “In-Situ” composting is a passive, cold composting approach to amending the soil while making use of kitchen scraps and yard debris. The primary difference between this method and active composting is that there is no turning involved. Instead of building a compost pile or using a tumbler to aggregate the ingredients and accelerate decomposition through the heating process, in-ground composting takes advantage of the slower, natural decomposition process.
Simply put, in-ground composting works by digging a hole or trench into the ground and placing a mixture of nitrogen and carbon-rich organic material inside. The hole is then covered with soil and left to decompose as nature dictates.
In-ground composting offers multiple advantages. Here’s just a few:
Lazy, fool-proof composting.
Kitchen scraps, collected leaves, and grass clippings can be put to good use without obsessing over nitrogen and carbon levels, lasagna layering techniques, or the required frequency of aggregation to keep the pile heated. I do this myself all of the time and trust me, if I can do it and be successful with it, you can too!
Soil can be significantly improved over time.
I’ve witnessed the positive effects of this approach first hand. While adding a layer of finished compost to the surface of your soil does offer benefit, it pales in comparison to the effect of deep soil integration.
By digging into the ground and adding organic material, you are changing the structure, texture, and composition of the soil while providing essential nutrients.
No “turning” or other maintenance required!
Unlike active composting which requires turning and active involvement, in-ground cold composting is something that can be completed in a few minutes and ignored. There is no ongoing work to be done.
In-ground composting is not limited by small quantities.
As the University of Illinois Extension explains, compost piles require mass to heat up effectively. They recommend a pile no smaller than 3 feet wide, deep, and high (source). Depending on your situation, it can take quite a while to collect that much raw organic material.
In-ground composting, on the other hand, can be done at any time with any quantity of material.
Encourages Natural Worm Populations In Soil
If there is one area where in-ground cold composting really shines it is in the encouragement of worm populations in your soil. When you bury organic material you are providing a smorgasbord of nutrients not only for the soil but for worms.
As those worms feast they will move out into the surrounding soil and deposit nutrient-dense castings, furthering the soil’s improvement.
Many “golden rules” of composting don’t apply.
Common “best-practice” composting rules don’t matter as much when you are burying scraps.
- Adding citrus, for example, is often discouraged when practicing active composting for fear of increasing the acidity of the material.
- Another example is eggs. When adding eggshells to an active compost pile it is recommended to crush the shells first. This helps accelerate the decomposition process.
But this doesn’t matter when you are doing in-ground composting to improve the soil in your yard. I commonly put uncrushed eggshells, citrus peels, and other “no-nos” into the ground.
I don’t add meat or dairy of course but overall, in-ground composting is much less restrictive.
Prepare Outlying Soil For Future Growth of Plants or Trees
I planted a small lemon tree last year. It was not much more than a twig. Because my yard contains hard clay soil, I knew going into this process that it would present challenges. Not just in getting the tree established but in providing a way to ensure its continual growth.
I routinely incorporate organic material into the soil outside of the root line. This ensures that as the tree grows its roots will push into nutrient-rich soil that will feed it and allow it to thrive.
It has worked wonderfully to improve the surrounding hard clay soil. The lemon tree is hearty and putting on fruit because it has access to the essential nutrients that it needs to grow.
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What To Add To An In-Ground Compost Hole?
I find it easiest to let my family’s weekly food consumption dictate the ingredients in my compost holes. Eggshells, of course, are a mainstay, as are coffee grounds. Depending on the week my concoction will include spinach that’s started to wilt, cucumber peelings, dryer lint, apple cores, paper towels, paper towel rolls, grapefruit peels, and maybe some tomatoes or celery that’s spent a little too long in the back of the fridge.
Every week is a little different so every hole is somewhat unique. It doesn’t matter. I tend to lay some dead leaves or pine straw in the bottom of the hole just to make sure I’ve got that carbon ingredient if I’m lacking carbon sources that week but there’s not much thought that goes into it beyond that.
Types of In-Ground Compost Holes
There are countless ways to do this but the three primary methods for in-ground composting are dig and drop compost holes, trench composting, and my favorite method for truly deep soil integration, drilling holes. Let’s briefly cover each of these.
Dig And Drop Composting
This is exactly what it sounds like and is the simplest approach to in-ground composting. All that’s needed is a shovel. Dig the hole, fill it with your kitchen scraps or yard debris, and cover it back up. I literally do this every Saturday morning, weather permitting. It takes just a few minutes and I can bury an entire week’s worth of scraps that would have otherwise ended up in a landfill somewhere. And with an average of 30% of what goes into our trash bags each week being biodegradable material (source), it’s nice to know that this project has a positive environmental impact.
There are a couple of ways I do this. If I am digging where I have an established lawn (alternative for existing lawns is listed further down in this article – see “drilling compost holes”), I like to take my time and keep the grass sod intact. Then, I can simply lay it back over the organic material (I add a few inches of soil between the scraps and the sod) and it is hardly noticeable when I’m done.
If I’m working with a bare spot in my yard, I will bury the material and then use some form of bedding material such as a raised bed soil and mix that with the natural soil in my yard (which is mostly clay). This helps to improve the soil a little on the surface while the organic material works to provide longterm benefit deeper underground.
To learn more about dig and drop composting, read my article on this super-easy method of putting your kitchen scraps to good use!
Based on the same principle as dig and drop but with a little more work involved, this method involves literally digging a trench instead of a single hole. The advantage of this approach is that you can bury a lot more organic material at once. A disadvantage, however, is that it does require more shoveling in a single session. Some people believe that before you can cover up a trench compost pile you need to fill the entire thing. That’s not true. You can begin at one end, adding organic material and burying that section then moving down the trench as more material becomes available.
Trench composting is commonly used in the space between rows of garden plants (source).
Drilling Compost Holes
The two previous examples have the advantage of disposing of larger piles of organic material at once. And although they do provide deeper integration of soil improvement than topdressing and core aeration, they lack the ability to really take the organic material into the deeper layers of soil (that is unless you are able to dig really deep or use some form of machinery).
The other disadvantage to dig and drop and trench composting is that they are not always suitable for an existing lawn. They work GREAT when you preparing a yard for grass but what if you already have an established lawn? Chances are you are not going to want to go digging large holes all over it.
The best solution, in this case, is drilling. Using a special large drill bit designed especially for soil, you can drill deep into the ground and fill the hole with organic material with minimal impact to the aesthetics of your yard.
Does In-Ground Composting Attract Ants And Rodents?
I do occasionally notice ant mounds in areas where I’ve buried kitchen scraps and yard debris. I don’t worry about it too much since ants actually provide benefit to my clay soil yard. They will do their part in nature’s decomposition process when they show up. But the truth is I don’t see this happen that often.
As for rodents, I have never had a single compost hole dug up by any type of critter. I always cover my scraps with at least a couple of inches of soil, usually a little more. Despite an abundance of raccoons, armadillos, field rats, and countless other outdoor pests that roam Southeast Texas, I’ve yet to have any issue.
Active composting offers many advantages when it comes to quickly converting organic material into usable soil. If you are needing compost quickly for a garden, flower bed, or lawn top dressing, then this is the way to go.
On the other hand, if you are simply looking for a quick and easy way to put kitchen scraps to good use, gradually improve your soil in the process, and lower the amount of biodegradable material that you send to landfills, these in-ground composting techniques are excellent options.
Above all else, just remember that while there is some science involved in composting, you don’t have to be a scientist to be successful at it. Just do something!