Is Mushroom Compost Good For Gardens?

Due to its unique combination of ingredients and low acidity, mushroom soil has become popular among gardeners. It helps because it is incredibly cheap to make. Because of this, a lot of people wonder whether mushroom compost is good for gardens.

Mushroom compost is good for gardens. In most cases, but mushroom compost should be used on seedlings with caution.

You should also avoid using it on plants that are very sensitive to salt, or those that demand very acidic soil. 

Let’s explain this in a bit more depth.

Mushroom compost is a very complex soil, and there are a few things that you should know before you decide to sprinkle it all over your garden.

What Is Mushroom Compost? 

Contrary to popular belief, mushroom compost is not made from mushrooms. Instead, it is a by-product of the mushroom farming industry. Mushroom compost is essentially ‘spent’ compost.

Once the mushroom farmers are finished with it, they bag it up, and it gets solid.

The ingredient list for mushroom compost can vary slightly. It all depends on the farmer and the type of mushroom that they were growing. However, mushroom soil is likely to include:

  • Manure (chicken and horse)
  • Hay
  • Gypsum
  • Straw
  • Sphagnum Moss
  • Lime
  • Corn

A few other organic materials may be mixed in, but those are your basics. The result is a very nutrient-rich soil that provides everything that mushrooms need to thrive.

There may be some mushroom residue left over, but the compost will have been sterilized, so this shouldn’t grow.

Mushroom compost is loved by gardeners for a few reasons.

The main being the nutrients.

Because mushroom compost has been used before, it won’t have the same number of nutrients as it did when originally used, but there are still some there, and your plants will love them.

Because this is a slow-release fertilizer with a lower number of nutrients than other fertilizers, it does discourage weed growth a little.

So, if you normally have issues with weeds, spread some mushroom compost around. It could help. Slower-release fertilizers also put less stress on weaker plants.

Mushroom compost also retains water incredibly well. This means that you’ll need to water your plants far less if you have porous soil.

Is Mushroom Compost Good For Gardens?

For the most part, mushroom compost is great for gardens. There are a few exceptions (see the next section).

Mushroom compost works best when you have plants that love alkaline conditions, but when your soil may be a touch acidic.

Mushroom compost is somewhere between 6.6 pH and 7.0 pH, although it does become more alkaline with repeated use. So, take care with more sensitive plants.

Since most plants and crops crave non-acidic soil, mushroom compost is ideal for use in the garden.

It especially comes in handy when you are growing most vegetables. Spread a thin layer over your crops, and it could protect them from certain diseases such as clubroot.

Mushroom compost is good for gardens when:

  • Your garden has acidic soil, and you want to plant things that want something more alkaline.
  • You are planting a lot of vegetable crops.
  • When your plants need a good slow-release fertilizer i.e., the plants are overly sensitive to rapid growth conditions.

Do bear in mind that while mushroom compost is nutrient-dense, there are better fertilizers if you have particularly nutrient-hungry plants.

Mushroom compost is, mostly, loved because it is cheap. As it is a slow-release fertilizer, the mushroom compost doesn’t put a huge amount of stress on the plants. This can give them more natural growth.

We can also recommend using mushroom compost if you have porous soil. Mushroom compost, due to its high salt content, retains water very well.

This can keep the plant’s roots well-nourished, and there is less of a need for you to constantly water them.

When You Should Avoid Using Mushroom Compost 

Avoid using mushroom compost on any plants that need acidic soil.

This rules out pretty much every type of fruit, but you’ll have to do your research on plants.

As we said, mushroom compost is between 6.6pH and 7pH, so can easily ‘convert’ acidic soil to something more alkaline.

You may also want to avoid using mushroom compost if your plants are especially sensitive to salt.

Mushroom compost is incredibly high in salt and with each reuse, the salt content climbs even higher.

Finally, avoid using mushroom compost on:

  • Seedlings
  • Any potted plants

Neither of those can deal with the high salt content of the mushroom compost, and the compost will kill them.

If you need to use a fertilizer, choose something designed especially for plants with weaker root systems.

Final Thoughts

Mushroom compost is good for most gardens. If you’re growing plants that favor alkaline soils, then mushroom compost is perfect.

I would not recommend it when dealing with plants that crave more acidic soils (including most fruits), or on seedlings.

Nadine is a passionate gardening writer sharing practical tips, innovative ideas, and valuable insights on plant and soil care, In her spare time, she tries to convince her plants to grow by singing them catchy tunes.

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