How to increase mycorrhizal fungi in soil? Garden Tips 2024

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Inside your soil are tons of microorganisms that you can’t see but are working hard. Mycorrhizal fungi are one of these and are incredibly important if you want healthy plants.

How to increase mycorrhizal fungi in soil: Even though your soil will have mycorrhizal fungi already in it, you can also purchase more fungi from online stores to increase the levels. To allow for the best circumstances for mycorrhizal fungi to grow, add mulch in the fall instead of tilling in the spring. Plant multiple types of plants for more varied root systems and don’t add pesticides, which can inadvertently kill the fungi.

What are mycorrhizal fungi?

It’s okay if you’re slightly confused by this term. After all, the fungus is usually seen in a negative term but here we want to explain how to increase mycorrhizal fungus.

Mycorrhizal fungi exist in soil but you can add more to improve your garden. They are readily available online and are a new and exciting element to modern gardening.

What do mycorrhizal fungi do?

There are many benefits of mycorrhizal fungi. They help to naturally increase the nutrient levels in your soil and your plants, resulting in larger, healthier crops.

They also help with water absorption which means you don’t have to water as often or worry if you are in drought conditions.

Finally, mycorrhizal fungi can help protect your plants from certain diseases. They have a symbiotic relationship with your garden, meaning they thrive in certain conditions and help keep your garden alive and thriving.

Where do you get mycorrhizal fungi?

The best way to get mycorrhizal fungi for your garden is by purchasing them online. This is a live organism and you need to prep it a bit before adding it to your garden.

There will be instructions on any packaging but basically, you should mix some of the fungi from the package with water. Then, you can add it to your garden.

Along with the instructions for mixing, there will also be a chart of how much of the new liquid you should use for the size of your garden. For example, if you are adding it to a 4-inch pot, then 80 millimeters is recommended whereas if you want to add it to your lawn, then 10 liters of water with 30 grams of fungi mixture will do for 1,000 square feet.

Why adding in manufactured mycorrhizal fungi can be useless to your soil

Even though you can purchase mycorrhizal fungus online, you might have better luck simply helping the fungus that is already in your soil. Store-bought mycorrhizal fungus is not always regulated so you don’t always know the quality you are receiving.

Ways to increase mycorrhizal fungi in soil

Right now, you have mycorrhizal fungi living in your soil. You can add more or work hard to increase what is already alive.

For the best results, both actions are recommended. Whatever you choose, however here are ways to increase these beneficial fungi.

Don’t till your soil

Even though many people have been regularly tilling their soil every spring, the practice is not actually as beneficial as was once thought. Inside this soil is a network of mycorrhizal fungi and if you disturb it, then you need to start all over again to have it grow.

The blades of a tiller can break apart the mycorrhizal fungi and the shorter this microorganism is, the less beneficial it is.

Add mulch

An alternative to tilling is adding mulch. Add a layer of bark mulch, straw, and leaves to your garden in the fall.

If you have trees in the area, leave the fallen leaves and if they are too large, mulch them with a lawnmower to break them up.

This decomposing organic layer will create a warm, inviting environment for the mycorrhizal fungi. They will continue to grow, even during winter, and the soil will be ready for planting in the spring without you having to worry about tilling.

Don’t add too much phosphorus

Most gardens need some ratio of nitrogen, phosphorus, and potassium. But adding too much of one can harm the balance that already exists.

Plants need phosphorus but if it is too much, they can’t regulate themselves and will take in too much.

If you aren’t sure about the phosphorus levels in your garden, a simple soil test will help you out. Aim for no more than 200 ppm of phosphorus although the ideal amount to encourage the growth of mycorrhizal fungi is between 50 and 100 ppm.

Don’t use pesticides

Yes, pesticides provide a necessary function. They get rid of weeds and insects that can damage or even destroy crops.

But pesticides can cause more damage than good. These pesticides can inadvertently attack mycorrhizal fungi, leaving your soil off-balance and deficient in nutrients.

Look for more organic methods, such as planting companion crops and using natural defenses such as ladybugs.

Add diverse crops

Instead of planting only one type of crop in one area, try to mix things up as much as possible. Underground, the different root structures will provide more variety and will help increase the growth of mycorrhizal fungi.

The fungi want to be exposed to different root structures. Planting different types of plants is the easiest way for this exposure.

Plants with extensive root structures will break up the soil naturally so that the soil isn’t too compact. This will allow the mycorrhizal fungi to grow and move around easier in the soil.

Water regularly

Mycorrhizal fungi need the basics to survive, including air and water. While you should water the soil regularly, you don’t want to flood it.

Aim for moist soil that has enough moisture in it to sustain the fungi. However, don’t over-water as the water will plug all the air holes in the soil, which will lead to the fungi dying.

Overwatering can also lead to soil erosion. As the top layer of soil washes away from too much water, mycorrhizal fungi will go with it.


Mycorrhizal fungi are common microorganisms in your soil. Keep the soil moist, add diverse plants, and don’t till your soil so that the mycorrhizal fungi will retain their symbiotic relationship and improve the health of your plants.

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