What Is Mushroom Compost Is It Good For Gardening?

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There are many different fertilizer options out there, each of which has its own purpose.

One such option is mushroom fertilizer, which has begun to see increased usage in gardens over the years.

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But what exactly is mushroom compost, and how do you use it in your garden?

What Is Mushroom Compost For Gardening?

Mushroom compost isn’t actually made out of mushrooms.

Instead, it’s a special composted fertilizer developed for growing mushrooms that can also be used in gardening

Note: Mushroom Compost Isn’t Fresh

When you pick up a package of mushroom fertilizer, it generally isn’t fresh.

Instead, you’re buying the used soil left over from the mushroom-growing industry.

Fresh mushroom fertilizer is too potent for most plants, as fungi normally grow on decomposing matter.

In essence, the mushrooms rely on nutrients from the soil to make up for their lack of chlorophyll, breaking down the special fertilizer mix into proper compost in the process.

This compost is high in organic matter and is one of the closest fertilizers to natural forest soil.

What Is Mushroom Fertilizer Made of?

The exact makeup of mushroom fertilizer varies from one farmer to the next.

In general, however, most mushroom composts are made of the following:

  • Chopped straw (especially rye)
  • Various compounds high in nitrogen
  • Gypsum
  • Horse or poultry manure
  • Water

Some other common ingredients include:

  • Ammonium nitrate
  • Canola meal
  • Corn cobs
  • Cottonseed meal
  • Grape solids (a byproduct of winemaking)
  • Lime
  • Peat moss
  • Potash
  • Soybean meal
  • Urea
  • Used horse bedding

Regardless of the individual ingredients, the resulting blend provides mushrooms with all the nutrition they need.

Meanwhile, the aid of the mushrooms in the composting process, during which the composting soil reaches high temperatures.

This means the resulting soil is naturally free of seeds and pathogens.

What Are The Benefits Of Mushroom Compost?

Mushroom compost is quite high in organic matter and can be used as an amendment in garden settings.

Depending on the recipe, the compost has an NPK of 1-0.2-1.3, although the nitrogen can be as high as 2% percent.

The compost can improve the overall quality of clay soils over time and replenish other soils.

It improves the water capacity of the soil, as well as invites plenty of beneficial microbial life.

Furthermore, the organic material is unstable, making it easier for your plants to process.

This attracts earthworms, which help to aerate the soil and further break down the compost.

When used as a mulch, it keeps plants warm and feeds them.

Finally, it’s a slow-release fertilizer and naturally high in calcium content.

The Drawbacks Of Mushroom Compost

Before using mushroom compost in a garden, it must be aged at least 2 years.

Most store-bought compost has already been aged, but this is something you mustn’t forget if you plan to make it yourself.

Additionally, you cannot use this compost with any plants sensitive to salts, such as azaleas, blueberries, camellias, and rhododendrons.

Due to its high organic nature, mushroom compost can interfere with water drainage, leading to a higher risk of fungal infection or rot for water-sensitive plants.

In fact, using this compost as a top dressing can often create soggy soil no matter how well-draining the underlying soil is, meaning special care must be taken to pick application methods suitable for a given plant’s needs.

Avoid using mushroom fertilizer directly on seedlings and other young plants, as the combination of ammonia and salts can easily kill an immature plant.

Oddly enough, mushroom compost can often be alkaline despite the organic content, especially if the chalk was an ingredient.

Be sure to test the compost’s pH level if you aren’t sure and compensate as needed to ensure a resulting pH level your plants can tolerate.

Finally, keep in mind that mushroom compost is generally sterile when you buy it (unless noted on the package), meaning it will attract microbial life but doesn’t come with any out of the bag.

You’ll have to introduce beneficial nematodes and other life by adding them to the fertilizer or having colonies already present in the soil.

Mushroom Compost Tea: The Safest Method

Making a compost tea is perhaps the safest way to apply your mushroom fertilizer, as it dilutes the compost and helps it absorb into the ground easier.

Just mix 1 part compost to 4 parts water and spray it as you would any other liquid fertilizer.

The dilution will also help prevent plants from getting a big dose of salts all at once.

Amending Soil with Mushroom Compost

As we mentioned earlier, mushroom compost can be harmful to young plants.

However, if you thoroughly blend the compost into your garden’s soil before planting, this risk is mostly mitigated.

Many gardeners prefer to amend the soil during the winter, which not only allows the compost to break down partially, but will also reduce water retention when planting season arrives.

To amend potted plants, you’ll want to blend 1 part compost with 3 parts soil.

However, you should generally blend 3″ inches into the top 6″ inches of soil for gardens.

Using Mushroom Compost as a Mulch or Top Dressing

You’ll need to be careful when using mushroom compost as a top dressing, but it can be quite effective if done right.

Sprinkle a light layer over your lawn to boost the grass gently.

To top-dressing your garden, you’ll need to get down and dirty.

Add 1″ to 2″ inches around each plant, leaving a gap between the stems and compost, so there’s less risk of damage.

The rain will slowly dissolve the compost, which will also serve as a barrier against weeds.

Can I Make My Own Mushroom Compost?

It’s a bit of a complicated process, but it’s entirely possible to make mushroom compost at home (with or without the mushrooms).

One of the more basic recipes is as follows:

  • Soak 5 bales of straw in water, then allow them to drain for 24 hours.
  • Take the straw to your composting area and spread out one bale.
  • Top the straw with 2 ¼ pounds of gypsum and 77 pounds of horse (or poultry) manure.
  • Repeat until you’ve gone through all of the straw.
  • Allow the compost to reach an internal temperature of at least 160° degrees Fahrenheit for several days straight.
  • Be sure to turn the compost occasionally, so the outer materials spend time in the middle of the pile and dampen as needed.
  • Once the compost surface is no longer warm to the touch (generally after a few weeks), divide some into a smaller pile.
  • The second pile is for aging and will still need to be kept moist but doesn’t need to be turned.
  • When the second pile has aged several weeks and turned dark and rich, it has become a slightly richer version of spent mushroom compost.
  • Note that you’ll want to scale this recipe down for smaller-scale use and can add in other materials to achieve specific nutrient goals.

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