7 composting mistakes to avoid

Compost heap
Compost heap (Image credit: Shutterstock)

Composting is a great, sustainable way to turn organic materials into nutrient-rich soil to feed our gardens and improve lawncare. Whether it be our food scraps or yard waste, composting is a more natural, inexpensive way to grow veggies and plants, but also helps to cut down on our kitchen waste. And there are benefits of composting that enrich more than our yard

While it’s hardly rocket science to throw in our scraps and waste onto the compost heap, you might be making these composting mistakes when doing so. In fact, just making one or two of these composting mistakes could prevent waste from breaking down properly, or worse still, attract rats, mice or any other unwanted pests to your yard. 

Essentially, composting is a process where organic matter is broken down (or ‘eaten’), by naturally occurring microorganisms like worms, sowbugs, and nematodes. These break down the waste, changing its structure to create a healthy nourishment for soil. 

However, for this process to work well, your compost heap needs the right components and conditions to produce healthy nutrients for your yard. What’s more, it will save you money on buying expensive fertilizers in the long-run! So, if you want to have nutrient-rich soil all year round, here are 7 composting mistakes to avoid.

Plus, check out these 7 surprising household items to help your plants grow. And 7 composting tips everyone needs to know.

1. Not having the right balance of green and brown waste 

Composting leaves in a bin

Composting leaves in a bin (Image credit: Shutterstock)

Similar to making a recipe, compost needs a mixture of green and brown materials to ‘cook up’ together. Typically, brown (dry) materials are high-carbon, such as dried leaves, tree debris, straw, sawdust or shredded paper. While the green (wet) materials contain high levels of nitrogen which include fresh grass clippings, food scraps or even coffee grounds. Without the right balance, the compost will not properly decompose, or lack the essential nutrients it needs for fertile-rich soil.  

Experts recommend to start making your compost pile by mixing three parts brown materials with one part green material. It’s also best to wait until you have enough organic waste to make a compost heap at least 3 feet deep with both the green and brown items. 

2. Compost heap is too wet or too dry 

Watering compost heap

Watering compost heap (Image credit: Shutterstock)

Although it’s recommended to sprinkle water over your compost pile, a common mistake is overwatering (or underwatering!). If there’s too much water in your compost, it will become waterlogged and potentially drown those beneficial microorganisms at work. Plus, not only will this cause your heap to smell foul, but it will end up rotting instead of composting. 

If your compost pile looks too wet or smelly, add more (dry) brown items to absorb excess moisture, or turn over with a garden fork to aerate the heap. Similarly, if your compost heap looks extremely dry and brown, simply add more green items and slightly water to make it damp.

This will also affect the temperature of your compost, which should be between 141°F to 155°F. If in doubt, you can monitor the temperature with a compost thermometer like this Compost Thermometer Stainless Steel Dial ($9, Amazon), to be sure the materials are at the right temperature and decomposing properly.  

3. Throwing the wrong things in the compost 

The peel of an orange, lemon and lime

The peel of an orange, lemon and lime (Image credit: Shutterstock)

Another composting mistake we often make is throwing the wrong things onto the heap.While you might think that all things organic are compostable, there are things you should never throw on the compost heap

This is mainly because certain waste materials can contaminate, slow down or even stop your compost's decomposition process. Also, you don’t want to add anything potentially toxic to the soil, which could be harmful to you, or your homegrown plants. Worse still, certain foods will release a foul stench over time, which could attract pests and all sorts of vermin to your backyard!

These things include dairy products, meat or fish scraps, onion and garlic scraps, citrus peels, coated cardboard and chemically treated wood or garden waste. 

It’s recommended to compost vegetable scraps, non-acidic fruit waste, eggshells, coffee filters, leaves, and any untreated wood or garden waste. 

4. Putting in diseased plants 

Wilting houseplant

Wilting houseplant (Image credit: Shutterstock)

Similarly, never throw diseased or dying plants in the compost heap. While it might seem like the ideal place for repurposing lifeless plants, this is a no-no.

Typically, diseased plants are a result of a fungal or insect infestation that could inevitably spread in your compost heap. Infected plants would affect the quality, and not make healthy compost material for your yard. 

And while it takes hot temperatures of 141°F to 145°F for at least several days to kill such fungi or bacteria, most home compost bins never reach those high levels. So if you want the best, nutrient-rich compost, avoid this composting mistake. 

5. You don’t cover up food scraps 

Food scraps in compost

Food scraps in compost  (Image credit: Shutterstock)

Another common mistake is to not cover up food scraps, which tend to get smelly or attract rodents and other pests.

Instead, experts suggest adopting a lasagne-style method of composting. Start off with a layer of dried leaves on the bottom and create a hollow nest in the middle to place any food scraps. Completely cover the food waste with another thick layer of brown material, making sure none of the waste is exposed. Then you can repeat the layering process, making sure you have a balanced composition of green and brown waste.

6. Not turning it over enough 

Compost tumbler

Compost tumbler (Image credit: Shutterstock)

As much as we throw in our organic waste and let it ‘cook’ in the compost heap, we often forget to turn it over now and again. Just like growing plants, compost also needs oxygen and water to produce top, healthy soil.

As it’s decomposing, the center of the pile can become oxygen-starved, and would need aerating. Stirring the compost pile thoroughly will help it cook faster and prevent organic materials from becoming flattened and smelly.

Simply stir the pile around with a fork or spade to allow air to all parts of the compost. Just remember not to overfill your compost heap, as you won’t have enough room for the fork to turn it over properly. 

If you have a compact yard or new to the world of composting, you can invest in a compost tumbler. This rotating compost bin is easy to use, and features aeration homes allowing air each time you turn it. Tumblers available online like this FCMP Outdoor IM4000 Dual Chamber Tumbling Composter ($76, Amazon), are a great option for beginners. 

Ideally, turning compost should be done about once or twice a week; This will give it enough aeration to thrive. 

7. Overfilling your compost heap 

Compost heap

Compost heap (Image credit: Shutterstock)

You might want to speed up the process, but another composting mistake is to overfill your heap. If you add too much waste, it won’t allow enough space for everything to decompose properly.

In addition, overfilling your heap will make it tricky to turn over and aerate the compost thoroughly. Plus, it would most likely end up a messy task!

Depending on the temperature of your pile, it usually takes between three weeks and three months to get the right compost texture. And when you have more surface area, this allows all the beneficial microbes to do their work much faster. Ideally, you want an earthy, crumbly, dark texture before you can use it around your yard. So don’t delay the process by literally piling everything onto your heap.  

How long does it take to make compost? 

Depending on your materials, conditions, and method, it could take anywhere from a several weeks to several years to make compost. 

More from Tom's Guide

Cynthia Lawrence
Content Editor, Homes

As the Homes Content Editor, Cynthia Lawrence covers all things homes, interior decorating, and garden-related. She has a wealth of editorial experience testing the latest, ‘must-have’ home appliances, writing buying guides and the handy ‘how to’ features. 

Her work has been published in various titles including, T3, Top Ten Reviews, Ideal Home, Real Homes, Livingetc. and House Beautiful, amongst many.

With a rather unhealthy obsession for all things homes and interiors, she also has an interior design blog for style inspiration and savvy storage solutions (get rid of that clutter!). When she’s not testing cool products, she’ll be searching online for more decor ideas to spruce up her family home or looking for a great bargain!

  • TimGeho
    The things that make compost are mostly fungi and bacteria, not worms, sowbugs, and nematodes. A proper copost pile will get too hot for these to live. The heat is what makes bad things die, such as most diseases, seeds, critters, etc.
  • Dibbly
    This article has so much wrong with it that it's hard to figure out where to start.

    As the poster above mentioned, compost is NOT made by sow bugs. Moreover, a good compost pile will become very hot if it has sufficient materials in decent proportions. That heat helps destroy undesirable things as well.

    I have several citrus trees and compost a lot of lemon, orange, and lime rinds. They disappear in a matter of days and they cause no problems, In fact, generally I just bury food scraps in the garden and the tomatoes are quite happy with that.

    Meat and dairy products are actually fantastic for compost - they are "greens" in that they contain a lot of nitrogen. If you simply throw them on top of your pile, you will attract crows, seagulls, flies, rats, cats, and other undesirables. So don't put them on top. Duh. Bury them and they're fine. I compost shells from shrimp, lobster, etc., and fat trimmings from chicken, beef, lamb, etc. What exactly do you think happened to all the people who died over the centuries? They became compost.

    There is no need to turn your pile at all. And those rolling bins are too small to generate enough heat and rolling the compost around simply compacts it into a tight mass. Better to just do it on the ground somewhere. You CAN do it in a big garbage can, but then you'd have to dump it once in a while and turn it, because again, there won't be enough mass to generate the required heat and all the moisture will settle to the bottom where it will rot whatever is there. However, it will also attract a lot of flies and you will have hundreds of maggots and if you have chickens, they will be in heaven. If you're lucky enough to have them, they're excellent because their poop is full of nitrogen and they'll pick out bugs and parasites and their eggs will be superb.

    And finally, eggshells do not really compost at all. They get broken up but if you leave them alone, they will last for many many years. If you want to release the calcium they contain, which is good for preventing end-rot on your tomatoes, you need to crush them up and then add some vinegar and water. Let that bubble up for a while and then further dilute it with more water and use it to water your plants. You can throw those eggshell pieces into the garden as well, since they're partly dissolved at that point they will decompose much faster. And they will not prevent slugs or snails from eating your plants. That's another old wives tale.
  • Kaliska
    Dibbly said:
    And finally, eggshells do not really compost at all. They get broken up but if you leave them alone, they will last for many many years. If you want to release the calcium they contain, which is good for preventing end-rot on your tomatoes, you need to crush them up and then add some vinegar and water. Let that bubble up for a while and then further dilute it with more water and use it to water your plants. You can throw those eggshell pieces into the garden as well, since they're partly dissolved at that point they will decompose much faster. And they will not prevent slugs or snails from eating your plants. That's another old wives tale.

    Egg shells and other calcium sources do not prevent blossom end rot in most cases. Several Universities have done their own studies and experiments along with other sources that found soil tests of locations with end rot including tomato gardens were rarely deficient in calcium. The problem is calcium uptake.

    One issue is the use of epsom salt in gardening. Magnesium prevents the use of calcium in plants and most soils aren't low in magnesium. Epsom salt is magnesium sulfate and even the amounts used to try to benefit plants can reduce calcium. When people try to use it in DIY herbicide mixes at high concentrations it's practically a guaranteed problem for some plants. Along with some concerns of run off. Magnesium doesn't get bound up in the soil so high concentration areas will steadily rinse out to other areas and eventually the water table or storm drains if applied frequently or in high concentrations. Overall it is bad unless used carefully and preferably accompanied by a soil test.

    Excessive ammonia levels will also reduce calcium usage and can also be the fault of gardening practices in an attempt to improve plant growth. Heavy applications of high nitrogen fertilizer has multiple negatives that can contribute to end rot. A lot of rich compost is actually a bad thing in many situations. Although not as bad as attempts to use concentrated fertilizers whether commercial or DIY options when you don't actually know your soil conditions or time their usage correctly.

    Plants also need a good root system and enough water to move calcium. Concentrating on fertilizing for top growth, flower, and fruit production instead of making certain the plant puts energy into a large root system can reduce nutrient uptake. Diseases like end rot can occur from improper fertilization and even high nitrogen compost applications. Any resulting food items are also lower in useful nutrition.

    A final potential cause is that failure to maintain adequate water will reduce all nutrient usage including calcium needed to prevent end rot.

    Unless you've tested your soil to know otherwise most ag extensions, university horticultural programs, and botanists point to other gardening practices and improper fertilization or management of plant growth and soil conditions as causes of end rot. Not a lack of calcium in the soil. High magnesium, high ammonia or nitrogen, high potassium, high salinity, rapid growth, drought, low humidity, and excessive heat are known to contribute to end rot by interfering with calcium uptake or transport throughout the plant. Since all stressful conditions, negative impacts on root development and improper water can potentially lead to end rot there is no single solution for it.

    It has been proven calcium can be absorbed by the leaves and fruit of tomatos to target the problem area and potentially bypass whatever issue is reducing how much calcium reaches the fruit. Most end rot sprays attempt to deliver calcium more directly into the needed area. Overall though you need to look at all the possible causes to determine what you are doing wrong or what is wrong with your soil.

    Egg shells are a more balanced source of minerals with actually quite a few different minerals in them. Including them instead of more concentrated sources like epsom salt and chemical fertilizers can avoid over fertilizing the wrong minerals and reduce end rot. Only if you don't also overload your soil with other sources of those minerals and ammonia or nitrogen containing fertilizers.

    Egg shells do provide some food to beneficial soil organisms and can increase microbe population and diversity in compost bins and soil. They contain about 5% organic matter and the rest minerals. Otherwise they wouldn't be so prone to attracting pests and a potential concern for salmonella even when the egg contained inside has been put to other uses. A hot pile should eliminate salmonella risk but those with small piles or turners are sometimes advised to at least make sure all shells are heat treated before crushing and adding to compost containers.

    Majority of the shell is very stable calcium carbonate so after the organic part is eliminated rapidly the rest of the shell will slowly dissolve rather than decompose. It does help to make the pieces smaller and keep compost piles from excessively drying out.

    Egg shells also aid worm digestion (I never looked up why) and have been shown to sometimes deter slugs and snails so may be of more benefit applied directly around plants in garden soil than add to your compost bin.
  • TimGeho
    If you use egg shells consider doing what I do. I heat treat small bunches of shells in my microwave to kill any unwanted pathogens. I then store them in an airtight jar until I have a good sized bunch. Then I use a coffee grinder to render them into tiny bits. It helps the organic part to get composted easier and the rest can be used by the bacteria as discussed in the prior post. It is more spread out in your soil than large bits Use the coffee grinder just for egg shells or crab shells. It can produce dust so I do it in an open garage.

    Another tip when making compost. Save some good compost and use it to introduce the proper bacteria and fungi into your new pile. Layer a bit along with your other ingredients.
    Many bacteria use a coating on the fungal filaments to move from organic bits to other bits since they can't jump open spaces. The coating on fungal hyphae is called glomalin. Glomalin has been estimated to contain 1/3 to 1/2 of all soil based carbon that has been sequestered by plants. Fungi are what transfers most of the nutrients that most plants use from the soil to the plant.