Mycorrhizal fungi are microscopic soil organisms that form mutually beneficial relationships with plant roots. These symbiotic fungi enhance nutrient and water uptake improve soil structure, and bolster plants’ defenses. While mycorrhizal inoculants are often applied at planting time I frequently get asked – can I add mycorrhizal fungi after planting?
The short answer is yes! Adding mycorrhizal fungi after planting can have many benefits as long as you follow a few important rules. This article will talk about what mycorrhizal fungi are, why they are good for plants, and the best ways to add them to gardens and landscapes that are already there.
What Are Mycorrhizal Fungi?
Mycorrhizal fungi live in symbiotic relationships with more than 90% of plant species. This word comes from the Greek words for “root” and “fungus.” These helpful fungi live in plant root cells and send out thread-like hyphae into the soil around the plant.
There are several types of mycorrhizal associations. The most common are:
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Arbuscular mycorrhizal fungi (AMF): These fungi get into root cells and build structures called arbuscules that help nutrients move between plants. AMF associate with most vegetables, herbs, grasses, and flowering plants.
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Ectomycorrhizal fungi (EMF) – They form a sheath around root tips and connect with the roots between cells. EMF are found with trees like pines, oaks, birches, and firs.
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Ericoid mycorrhizal fungi: These fungi work best with heath plants like heathers, blueberries, azaleas, and rhododendrons.
Benefits of Mycorrhizal Fungi
When mycorrhizal hyphae grow into the surrounding soil, they greatly expand the surface area for absorption of water and key nutrients like nitrogen, phosphorus, and micronutrients This leads to benefits like
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Improved nutrient uptake – Mycorrhizal fungi are especially adept at absorbing phosphorus and transporting it to the host plant.
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Increased drought tolerance – The extensive fungal network also improves plants’ ability to access soil moisture.
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Enhanced pathogen resistance – Mycorrhizal colonization triggers increased production of plant defense compounds.
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Improved soil structure – Fungal hyphae and secretions act like a biological glue to stabilize soil aggregates.
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Greater plant growth and yields – With enhanced nutrient and water uptake, mycorrhizal plants typically show increased vigor and productivity.
When to Apply Mycorrhizal Fungi
Ideally, mycorrhizal inoculants should be applied at planting time so fungal colonization of young roots is immediate. But you can still derive benefits from adding them after plant establishment.
Newly planted specimens – Mycorrhizal inoculation at planting helps reduce transplant shock and supports quick establishment.
Existing vegetation – Established plants grow new roots each year that can host new mycorrhizal colonization.
Anytime fertility is low – Mycorrhizal fungi are great for boosting nutrient absorption in deficient soils.
How to Apply Mycorrhizal Fungi Post-Planting
When adding mycorrhizal fungi to already existing plants, the goal is to distribute inoculant into the root zone. Here are some effective application methods:
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Root dip – For new plantings, dip bare roots in mycorrhizal powder before planting.
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Soil inoculation – Sprinkle fungal powder around drip line of existing plants. Mix into soil 2-4 inches deep.
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Liquid application – Water in mycorrhizal spores suspended in water around plants.
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Tree injection – Inject liquid inoculant into root flares of mature trees using specialized equipment.
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Seed inoculation – For lawns or seed beds, mix dry inoculant into seeds before sowing.
Follow label rates for amounts to apply based on plant types and areas covered. Water thoroughly after application to disperse fungi into surrounding soil.
Timing of Post-Planting Applications
When during the season you apply mycorrhizal inoculants after planting can impact how quickly the fungi colonize roots and impart benefits:
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Spring – Favorable cool, moist conditions allow fungi to proliferate.
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Summer – Hot, dry weather may inhibit fungal establishment. Focus on keeping soil moist.
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Fall – Moderate fall temperatures support mycorrhizal spread prior to winter dormancy.
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Winter – Avoid frozen soils, but an early winter application allows fungi to colonize roots before spring growth flush.
Factors Affecting Success
Several factors influence the efficacy of post-planting mycorrhizal applications:
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Soil pH – Most species prefer a pH between 5.5 and 7. Extremely acidic or alkaline conditions inhibit fungi.
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Soil disturbance – Tillage and cultivating destroy fungal hyphae. Limit soil work after inoculating.
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Soil nutrients – Very high phosphorus can hinder mycorrhizal colonization. Avoid over-fertilizing.
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Plant/fungi compatibility – Match inoculant with appropriate host plants for best results.
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Watering – Adequate, consistent moisture supports establishment in dry soils.
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Competition – Other soil microbes may compete with introduced fungi for root space and nutrients.
Observing Results
Don’t expect immediate dramatic changes after applying mycorrhizal inoculants. Fungal colonization is a gradual process, so be patient. Noticeable benefits like improved transplant success, increased flowering and fruiting, and greater drought tolerance may take one to several growing seasons to observe.
Signs your plants are partnering successfully with mycorrhizal fungi include:
- Extensive root development with abundant fine feeder roots
- Dark coloring and sheathing on roots (with EMF)
- Increased plant vigor and yield
- Enhanced fruiting and flowering
- Heightened resistance to wilting
- Reduced need for fertilization
The Takeaway on Post-Planting Inoculation
The key points to remember about incorporating mycorrhizal fungi after plant establishment are:
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Mycorrhizal inoculation after planting is beneficial and feasible.
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Use proper application techniques that deliver fungi to the root zone.
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Time applications for optimal growing conditions.
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Monitor soil nutrients, moisture, and plant health when using fungi.
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Allow time for colonization to occur and benefits to accrue.
Employing some basic best practices will set your mycorrhizae-infused plants up for success! Your existing vegetation will reap nutritional and protective advantages from partnering with these remarkable root symbionts.
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Empathy’s rootgrowTM Mycorrhizal Fungi comes as a granular additive that should be added to the planting hole when planting in open soil or containers. Make sure the plant’s roots touch the rootgrow, then backfill and water as usual.
Rootgrow™ Gel has been specially developed for bare root plants and trees, simply add the solution to water and dip the roots before planting as normal.
Garden Hack: Add Mycorrhizal Fungi to your Garden with MycoMaxx #ecofriendlygardening #gardenbed
FAQ
What are the disadvantages of mycorrhizal fungi?
stramonium, positive associations between AM fungi and plant fitness may not be proportional and, that at high colonization densities, mycorrhizae may have detrimental effects, perhaps by competing with plants for nutrients, or by interfering with other essential interactions.
Can you sprinkle mycorrhizae on top of soil?
Mycorrhizal products are often used by gardeners when sowing seeds, when transplanting, or to inoculate a bed before planting, working them into the top 4-6 inches. Inoculated soils will actually improve year after year, so it’s a sustainable product.
What plants don’t like mycorrhizal fungi?
In total, mycorrhizal fungi benefit 80 to 90 percent of all plant species. Plants that do not respond to mycorrhizae include azalea, beet, blueberry, broccoli, Brussels sprouts, cabbage/kale, carnation, cauliflower, collards, cranberry, heath, huckleberry, mustard, protea, rhododendron, sedge and spinach.
Can you use too much mycorrhizal?
You can’t use too much mycorrhizae on your plants. If you use more Big Foot Mycorrhizae than what the package says, it won’t hurt your plants or the soil. However, over-watering plants with any additive can lead to the soil and the plants’ roots not receiving enough oxygen.
Are mycorrhizal fungi good for plants?
Mycorrhizal fungi connect with plant roots and help them take in more water and nutrients. They work best when added when the plants are first planted, but you can also add mycorrhizal inoculants to plants that are already established.
How do I use mycorrhizal fungi?
Applying the right amount of Mycorrhizal Fungi or other plant biostimulants, like our GreenEden biological amendments, to the plant, soil, turf, etc. is important. will guarantee maximized results. When you apply Mycorrhizal Fungi, the aim is to make direct root contact.
When should I add mycorrhizal fungi?
Whatever the form of mycorrhizal inoculant, it is best to add it while the root is still young. The early plant roots colonization will allow the plant to benefit from the association maximally. The goal when you apply Mycorrhizal Fungi is to make direct root contact.
What is the relationship between mycorrhizae fungi and plants?
Plants for millions of years have depended on the mutually beneficial association with the mycorrhizae fungi. This symbiotic relationship has been observed for almost every plant in its natural habitat. The association has been known to aid plants in water and nutrient absorption from the soil.
How do I inoculate plant roots with mycorrhizal fungi?
Inoculating plant roots with mycorrhizal fungi can be approached in various ways. The goal is to ensure that the fungi come into direct contact with the plant roots for successful colonization. I’ve found that adding granular inoculant directly into the planting hole or mixing it with the seedlings’ potting soil can be effective.
Can I buy mycorrhizal fungi?
You can also buy mycorrhizal fungi and add it to the planting hole when planting new plants. This can help plants establish more quickly and boost healthy growth by supplying additional water and nutrients.