Can You Compost Mushrooms? (And Cooked Mushrooms Too?)

Mushrooms are widely known for their great taste and amazing health benefits. They are a low-calorie food that packs a nutritional punch including many health-boosting vitamins, minerals, and antioxidants. They have long been recognized as an important part of any diet, making for an excellent addition to your diet, adding flavor to many different recipes.

Mushrooms are also known to lower blood pressure, boost your immune system, and promote weight loss. Being that they are a popular dish, eaten by millions of people all over the world, there are bound to have leftovers, the majority of which end up in landfills. However, can there be another use for the mushrooms, where they can be an addition to the garden? This article analyses composting mushrooms.

Can Mushrooms Be Composted?

Yes, mushrooms are compostable. In fact, put all the mushrooms you want in the composting pile. Whether wild or commercial edible mushrooms, they can all be added to the composter, along with other kitchen scraps like vegetables, eggshells, leaves and organic recyclables normally found in a heap.

Mushrooms peelings and stalks from the kitchen rot down pretty quickly, although whole mushrooms can take a bit longer to fully decompose. Random fungi from around the garden can take longer still if the caps are quite tough and woody, such as birch polypores.

To ensure they decompose a bit quicker, make sure they are wet. And since spores can also be a problem, pick the mushrooms early before the spores have a chance to accumulate to stop them sprouting babies in the compost heap. Given their special attributes, mushrooms add several benefits to a healthy compost pile.

For starters, they are high in potassium, copper and phosphorus. One portabella mushroom has more potassium than a serving of orange juice. Mushrooms are the only good source of selenium from produce although most selenium comes from grains or animal sources.

Add mushrooms to the pile and all of these mineral goodies become part of the completed compost. The compost then feeds your plants and garden all these essential minerals. They are also a fruit of a vast mycelium network and as the network expands, it releases enzymes that break down into basic sugars and nutrients that efficiently feed plants and help them grow faster.

As nutrition is returned to the soil, carbon dioxide is emitted for plants to breathe. In return, the plants give the fungi sustenance the mushrooms cannot produce on their own. When mushrooms are in your finished compost, the benefits go right to the vegetables you eat.

Mushroom composting takes about 3 to 4 weeks to process, during which it is monitored closely by mushroom growers to maintain adequate temperatures. After the process is complete, the leftover compost is disposed of and sold as fertilizer.

Mushroom compost is generally sold in bags labelled as SMC (spent mushroom compost) or SMS (spent mushroom substrate). Mushroom compost is also available for purchase by the truckload or bushel, depending on its use in the garden. Mushroom compost can be used as a soil amendment for lawns, gardens, and container plants.

However, this product should be used with caution due to its high soluble salt levels. These salt levels can kill germinating seeds, harm young seedlings, and cause damage to salt-sensitive plants, like azaleas and rhododendrons.

The beneficial uses of mushroom compost, however, far outweigh the downside of high salt levels. Mushroom compost enriches the soil and supplies nutrients for the healthy growth of plants. It also increases the water-holding capacity of the soil, which decreases your watering needs.

Its potential uses make it ideal for most garden plants. It supports various types of plant growth, from fruits and vegetables to herbs and flowers. To get the greatest results when organic gardening with mushroom compost, thoroughly mix it in with the garden soil prior to planting or allow it to sit over winter and apply in spring.

Can I Put Cooked Mushrooms in the Compost?

Yes, cooked mushrooms can also be composted. They add several benefits to a compost pile, like potassium, copper and phosphorous. Adding mushrooms to the pile invites all these mineral goodies to become part of the completed compost. The compost then feeds your plants and garden all these essential minerals.

However, be careful about the cooked mushroom, the primary emphasis being paid to the fact that they are cooked. For starters, cooked food tends to invite pests, primarily because as they decompose, they produce stinking odors that are attractive to the pests.

Secondly, the cooked mushrooms will contain traces of cooking oil, which can make the composting process go anaerobic, the archenemy of normal aerobic composting.

As such, be sure to compost the cooked mushrooms in a hot compost. A cold compost pile can be a bit complicated to decompose, especially when working with cooked mushrooms or other cooked foods. If you do not have access to a Bokashi or hot compost, try placing the cooked mushroom at the center of the composting pile.

It is where it is the hottest and can produce similar results. The increased heat also ensures the cooked mushrooms compost quite quickly and does not produce bad smells.

This means the nosy pests will not know of cooked mushrooms being composted anywhere and if they do, the decomposition process will be over and you will have gotten the best from the mushrooms. Make sure you also aerate the compost and water the compost regularly so that it decomposes in its entirety.

Will Mushroom Compost Burn Plants?

Mushroom compost can burn plants, emphasis on the word ‘can’. In most cases, when you add mushroom compost to your soil, you might notice yellowish colourations on the leaves, also referred to as burning.

The truth is that there are a lot of things you need to consider before adding mushroom compost to your plants’ soil. You have to understand the nutrients that are deficient in your soil, before adding the mushroom compost.

In itself, mushroom compost is alkaline, meaning it will be deficient in some nutrients that your plants need. Therefore, test your soil to determine what nutrients your soil desperately needs. It will make it easy to determine if your soil needs the mushroom compost or if you will be better off with a fertilizer.

Burning occurs when you add too much mushroom compost, which has a high salt content. The higher level of salt can easily kill seedlings or burn your plants through dehydration.

According to the Oregon State University, “The soluble salts in undiluted mushroom compost are too concentrated for germinating seeds, young plants, and other salt-sensitive plants.” This is why you need to consider the soil test before adding compost or fertilizer to your garden.

Is Mushroom Compost Good for Roses?

Mushroom compost is good for roses. As already mentioned, mushroom compost comprises many valuable nutrients that can be passed on to the roses. However, be careful about how you add the compost. It is only recommended to put the mushroom compost in the bottom of the hole as fertilizer when planting the roses.

According to Heirloom Roses, they avoid recommending adding mushroom compost as a top dressing for the roses because some of their customers have reported problems with fungi being introduced into their rose gardens.

It has also been identified that mushroom compost is alkaline, at about 7.4, meaning it can neutralise overly acidic soils and alter their pH level. This is the main reason you should test your soil before adding the mushroom.

Unfortunately for this situation, roses prefer a soil pH close to the typical level for ordinary garden soil, which is slightly acidic to neutral, between 6.0 to 7.0. As such, the mushroom compost will affect the soil in which roses thrive.

You should therefore avoid using mushroom compost on roses as it might slow their proper growth and development. If you have to, then use the compost in minimal or manageable quantities.

Is Mushroom Compost Good for Fruit Trees?

Exactly, mushroom compost is good for fruit trees. It has high calcium levels, making the mushroom compost excellent for growing vegetables and fruits that thrive with a good calcium supply.

This type of compost is especially beneficial for growing tomatoes, as tomatoes often suffer from a blossom end rot as a result of having too little calcium available in their soil. However, be careful about using mushroom compost on small fruit trees. They are better off with organic fertilizer or a combination of the fertilizer and mulch or compost.

The compost alone can be too much for small fruit trees, as well as any other small plants and trees, as its high salt content will burn the trees and easily kill the seedlings or burn the fruit trees through dehydration.

Also, avoid using mushroom compost on fruits that prefer acidic soils like berries. They include blueberries, cranberries, lingonberries and heathland bilberries, all of which grow naturally in acidic soils, somewhere between 4.0 and 5.0 on the pH scale.

Mushroom compost is slightly alkaline, with a pH of about 7.4. this means that the compost, especially when added in large quantities or for a considerable amount of time, will slowly neutralize the soil and will eventually kill the acidity in the soil.

Consequently, the berries will not produce at their optimum levels. Excess mushroom compost will also burn the roots of these acid-loving fruits. For citrus fruits, just mulch the mushroom compost before the hot summer months arrive, to provide the soil with excellent moisture-holding capacity.

Is Mushroom Compost Good For Clay Soil?

Mushroom compost is good for clay soils. Clay is the densest, most compact soil type. It contains nutrients and has good water retention, but its compact nature makes it difficult to work in and difficult for plant roots to spread through.

Amending the clay soil with organic matter can help improve the workability and drainage properties of the soil and the one type of organic matter that is useful for this purpose is mushroom compost. It improves their texture and the compost should be mixed well with the clay soils.

Also mixing the topsoil with the mushroom compost will increase its organic content and will avoid any chalk build-up. Oh, and the mushroom compost is not composted mushrooms, but it is the leftover material that mushrooms were grown in.

Mushroom compost, in particular, made from well-rotted natural materials recycled from a mushroom-growing medium, is a good choice to amend clay because of its light, airy composition. It can, however, take some effort and time for the clay soils to become rich and fluffy.

Just carefully incorporate lighter materials that can transform even the heaviest soils in a relatively short amount of time. Just amend the soil in the spring or fall when the ground is not too wet. Fixing your clay soil with mushroom compost will also add the nutrients present in the compost to the soil, a property your crops will be grateful for.


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About Rinkesh

A true environmentalist by heart ❤️. Founded Conserve Energy Future with the sole motto of providing helpful information related to our rapidly depleting environment. Unless you strongly believe in Elon Musk‘s idea of making Mars as another habitable planet, do remember that there really is no 'Planet B' in this whole universe.