Top 8 Soil Inoculants for Plants (Editor’s Picks)

healthy roots inoculated

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Soil inoculant products are gaining popularity in organic, natural gardens as they are quick and effective in increasing beneficial soil microbes for plants.

There are many such products in the market.  Of the 8 most popular inoculant products in the market, we recommend Great White, Mikrobs, and Myco Bliss for different purposes. 

In this article, we will lay out the major factors you should consider when picking a microbial inoculant.  And we will also explain why we think the three mentioned are the best for your plants.

Quick Summary

  • We recommend Great White and Mikrobs as the best overall inoculant.  It fulfills all our criteria for a good soil inoculant with proven results from many users.  Great White is more expensive but with more strains and a higher concentration of mycorrhizal fungi, while Mikrobs is half the cost but has fewer strains and a lower concentration.  Other close contenders are Real Growers Recharge and MYCO+.
  • We recommend Myco Bliss as the best budget inoculant.  It contains 5 species of mycorrhizal fungi and is highly concentrated.  Most importantly, its smallest format (1 lb) is half the price compared to the other brands, and its largest format (20 lb) is one-fifth the price of other brands.  This product is the best for those who need to inoculate large lawn and garden areas.     

Soil Inoculant

Review

Editor's Pick

1. Great White

Pros

●     2 microbe types (14 species of mycorrhizal fungi, 2 species of Trichoderma)

●     highest concentration


Cons

●     Pricey

●     No Bacillus

Editor's Pick

2. Mikrobs

Pros

●     3 microbe types (4 strains of mycorrhizae, 3 strains of richoderma, 4 strains of bacillus)

●     High concentration of Trichoderma and bacillus

●     Macronutrients and growth hormone

●     Good value

Cons

●     Low concentration of mycorrhizal fungi

3. Real Growers Recharge

Pros

●     3 microbe types (4 strains of mycorrhizae, 2 strains of Trichoderma, 4 strains of Bacillus)

●     High concentration of Trichoderma and Bacillus

●     Key macronutrients


Cons

●     Low concentration of mycorrhizal fungi

●     Pricey

●     Available only in large formats (at least 16 oz)

4.  MYCO+ 

Pros

●     2 microbe types (4 strains of mycorrhizae, 1 strain of Trichoderma)

●     Macronutrients

●     Good value

●     Available in small packages (7 oz)

Cons

●     Low concentration of microbes

Best Budget Inoculant

5. Myco Bliss


Pros

●     1 microbe type (5 strains of mycorrhizal fungi)

●     Acceptable concentration of microbes

●     Cheapest and best value (for big bag)


Cons

●     Contains only mycorrhizal fungi

6. DYNOMYCO

Pros

●     1 microbe type (2 strains of mycorrhizal microbes)

●     High concentration of microbes


Cons

●     Contains only mycorrhizal microbes

7. Mikro-Root 

Pros

●     To supplement soil lacking in Trichoderma

Cons

●     Contains only Trichoderma

●     Pricey

8.  Botanicare Hydroguard

Pros

●     High concentration

●     Liquid form for hydroponics

Cons

●     Contains only Bacillus

●     Only 1 strain of Bacillus

●     Short shelf life of 6 months

Do mycorrhizae products work?

Mycorrhizal products or soil inoculant products are not fertilizers.  The products in the market generally contain three or one of the three major types of microbes, namely mycorrhizal fungi, Trichoderma, and Bacillus which are beneficial to plant growth.  

These microbes all form a mutually beneficial or symbiotic partnership with plants in improving the plants’ nutrition and protection in exchange for a sugary exudate secreted by the roots.   

In particular, mycorrhizal fungi improve the uptake of water and nutrients as their extensive network of thread-like hyphae can access faraway places in the soil that are beyond the reach of plant roots.

Trichoderma is a fungus that can stimulate root growth and serve as a fungicide to prevent pathogens from attacking the plant.

Bacillus is also called Rhizobacteria which can also prevent diseases and boost plant immunity.

The three microbe types can be used together to produce the best results in plant nutrition, yield, and plant health.

To learn more:  Top 3 inoculant types for plants (explained)

How to pick a good inoculant?

The efficacy of an inoculant depends on the number and types of microbes, the number of strains of each type of microbe, the concentration of microbes, shelf life, and cost of the product.

When selecting inoculants for plants, you should consider:

  1. Various types of beneficial microbes:  A good inoculant should have at least mycorrhizhal fungi and Trichoderma fungi (and ideally, also Bacillus or Rhizobacteria), as they serve different functions in the uptake of nutrients, stimulating root growth and increasing the plant’s immunity against diseases.
  1. Multiple strains of a microbe type:  Although over 80% of plants form symbiotic relationships with the Arbuscular mycorrhizal fungi, some plants still may only work with certain strains of the mycorrhizal fungi.  

    Therefore, having more strains of a microbe type can increase the success rate of partnering up with the plant species. 

    Most of the commonly found mycorrhizal fungi species are from the Glomus genus.
  1. High concentration of microbes:  The concentration of fungi is measured by the number of propagules or Colony Forming Units (CFU).  For fungi, a propagule is a spore used in reproduction. 

    Inoculants with a high concentration of fungal spores or propagules will reproduce and multiply more quickly, thus more quickly colonizing the roots. 

    This number can vary between 2 to 200,000 propagules per gram on different brands, so one should pay attention to this detail.  

    However, it may not be easy to compare different products as some measure the concentration in units of propagule and others in units of CFU, and there is no direct way to convert one measurement to another.
  1. Long shelf life:  Inoculants in powder or granular form generally have a long shelf life of about 2 years, whereas inoculants in liquid form have a much shorter shelf life of around 6 months only.  

    It is better to have a product that can last longer than a growing season and be used in the next season.
  1. Plant nutrients and growth hormones:  This is especially important if you will use the inoculant on sterilized potting mix or soil with little organic matter.  Having only microbes (workers), but no nutrients (food) in the soil for the workers to bring to the plant would not reap much of a result. 

    Some inoculant products also include plant growth hormones from seaweed extract/kelp, and also macronutrients from humic acid, amino acids, and sugar from molasses to give a quick boost to microbes.
  1. Cost:  This may not be a factor for those with only a few houseplants.  But it is definitely a concern for those with large gardens or soil areas to inoculate.  The standard cost for most inoculants is around US$3 per oz for a 7-8 oz (200 g) jar or bag of inoculant. 

Soil inoculant recommendations

1.  Great WhiteEditor’s pick

Verdict: 5/5

Great White receives probably the higher number of reviews for soil inoculants and is indeed a quality product. 

It contains 14 species of mycorrhizal fungi (which is the highest number of species of all products) and 2 species of Trichoderma

It also contains the highest concentration of microbes (200,000 propagules per gram) among all 8 products reviewed (which are generally around 200 propagules per gram).

It has received many top reviews with proven results of explosive root growth.

But the trade-off is that this product is pricey.  It costs almost US$7 per oz, which is more than double than other brands for its 8-oz format. There were also some complaints about receiving the smallest bottle only 1/2 or even 1/4th full.

Second, it only consists of mycorrhizal fungi and Trichoderma, and no Bacillus.

And it does not contain macronutrients and growth hormones for plants as in the other products.

After all, the high cost of this product is justified by the numerous strains and high concentration of mycorrhizal fungi.

For people who can afford to pay for this product, this is definitely the best choice.

We give this product a 5 out of 5. 

2. Mikrobs – Editor’s pick

Verdict: 5/5

Mikrobs is another quality product for gardeners who would like to have all the 3 types of microbes and a cheaper alternative to the Great White brand.  However, the trade-off is a rather low concentration of mycorrhizal fungi.

It combines all the 3 types of beneficial microbes, namely mycorrhizal fungi, Trichoderma, and Bacillus rhizobacteria.

It also contains multiple strains of microbes to increase the likelihood that they will be able to partner up with a variety of plants.  Specifically, there are 4 strains of mycorrhizal fungi (Glomus intraradices, Glomus mosseae, Glomus Aggregatum, Glomus Etunicatum), 3 strains of Trichoderma (Trichoderma Harzianum, Trichoderma Viride, Trichoderma Longibrachiatum), and 4 strains of Rhizobacteria (Bacillus Licheniformis, Bacillus Pumilus, Bacillus Subtills, Bacillus Megaterium). 

It contains a low concentration of mycorrhizal fungi (28 CFU/g), and high concentration of Trichoderma (15,000,000 CFU/g) and Bacillus (48,000,000 CFU/g).

The inoculant also contains key plant nutrients and growth hormones from seaweed extract (kelp), humic acid, fulvic acid, amino acids, and blackstrap molasses.

And it is good value, costing around US$3 per oz for an 8-oz pack.

For all these reasons, this product deserves a 5 out of 5.

3. Real Growers Recharge

Verdict: 4.5/5

Real Growers Recharge is a reputable brand for soil inoculants and is a close contender to Mikrobs. 

It is a blend of 3 types of beneficial microbes with very similar species type as Mikrobs.  They are mycorrhizhal fungi (4 strains: Glomus intraradices, Glomus mosseae, Glomus Aggregatum, Glomus Etunicatum), namely Trichoderma (2 strains: Trichoderma Harzianum, Trichoderma Reesei), Bacillus (4 strains: Bacillus Licheniformis, Bacillus Pumilus, Bacillus Subtills, Bacillus Megaterium), and mycorrhizae.

It also contains macronutrients and growth hormones from kelp, humic and fulvic acid, and molasses.

The product receives top Amazon reviews from customers who have reportedly seen noticeable results of robust, and healthier growth in their houseplants, lawns, and gardens after application.

It is also good value, costing around US$3.6 per oz.

However, this product contains a low concentration of mycorrhizal fungi (6.4 CFU/g for each species) and is more concentrated in Bacillus (100,000,000 CFU/g for each species) and Trichoderma (250,000 CFU/g for each species).

Another problem is that it is only available in the big format of 16 oz (454 g), which may give the impression that it is an expensive product.  The quantity may be too much for most home gardeners as each time you only use 1 tablespoon per gallon of water.

For these reasons, we give this inoculant a 4.5 out of 5.

4. MYCO+

Verdict: 4.5/5

MYCO+ is another top contender, and is less expensive than Real Growers Recharge.

It contains mycorrhizal fungi (4 strains:Glomus intraradices, Glomus mosseae, Glomus aggregatum, Glomus etunicatum) and Trichoderma (1 strain: Trichoderma harzianum). 

It contains macronutrients, namely nitrogen (3%), Potassium (3%), Magnesium (0.75%), Sulfur (1.5%) and Iron (0.1%).

The product has also received many positive customer reviews with proven results of increased root mass, better growth, and yield after application.

Most importantly, it is a good value (around $3 per oz for a 7-oz jar).  Also, it is available in small sizes (7oz or 200g), which is more convenient and suitable for home gardeners.

However, the major drawback is the low concentration of microbes, with only a total of 40 propagules per gram of the four mycorrhizal fungi strains.  And it does not contain Bacillus.

For these reasons, we give MYCO+ a 4.5 out of 5.

5. Myco bliss – Best Budget Inoculant

Verdict: 5/5

For people with many plants or a large lawn and garden area that need to be inoculated, we recommend Myco Bliss. 

This is a purely mycorrhizal soil inoculant. It contains five species of the mycorrhizal fungi, namely Rhizophagus irregularis, Rhizophagus aggregatus, Rhizophagus proliferum, Rhizophagus clarus, Claroideoglomus etunicatum

The concentration information of this product can be a little confusing because it states 175 propagules/g in the new packaging but 1000 propagules/gram in the old packaging.  In either case, the concentration is acceptable and not too low.

According to many customer reviews, the product results in a noticeable increase in yield and plant vigor, especially during and after transplanting seedlings.

Most importantly, this product offers the best value.  Their 1 lb bags cost only US$1.5 per oz, which is half the price compared to the other brands, and their 20 lb bags cost only around US$0.60 which is one-fifth of the price compared to the others.  And the brand is run by a small business.

Although there is only one type of microbe, for people who need to use a lot of inoculants, this would be an ideal budget product.  Its 2 lb bag can cover an acre of soil.

We give this product 4.5 out of 5.

6. DYNOMYCO

Verdict: 4/5

DYNOMYCO is a quality product for its value.

It contains only mycorrhizal fungi (2 strains: Glomus intraradices, Glomus mosseae) but in high concentration (900 propagules per gram). 

The product receives positive reviews from customers reporting improved plant growth.

Its cost is around US$4/oz, which is similar to most other inoculant products in the market.

Considering all aspects, we see this as an okay product, but we think that there are other better ones in the market.

We give this product a 4 out of 5.

7. Mikro-Root

Verdict: 3.5/5

We give Mikro-Root one of the lowest ratings among the 7 products reviewed.

The major flaw of this product is that it contains only the Trichoderma fungi (2 species: Trichoderma harzianum and Trichoderma viride).

It is also quite pricey, costing almost $8/oz considering the quantity of the product in only 2oz (56 g) and 4 oz (110 g) formats.

This product may be good for those who specifically know their soil lacks the Trichoderma fungi and want to supplement it with only this fungus.

We give this product a 3.5 of 5

8. Botanicare Hydroguard

Verdict: 3/5

We give this product the lowest rating among the 7 products reviewed.

This is a liquid inoculant designed primarily for hydroponics systems, but it may also be used for soils and potted plants.

The product features a high concentration of microbes (1000 propagules per gram) but in only one single species of Bacillus known as Bacillus amyloliquefaciens. This microbe stimulates root growth, breaks down organic matter into nutrients for the plant, and kills pathogens.

Although the product receives good reviews with proven results, there are also complaints about its short 6-month shelf life.  There is no specific reason why inoculants in liquid form have an advantage over powdered form because you can always dissolve the granular or powdered form in water to use it in hydroponic systems.  Therefore, in general, we recommend inoculants in granular or powdered form.

We give this product a 3 out of 5.

How to apply inoculants?

Inoculants can be applied to seeds, seedlings, mature plants, the lawn, and any plants including orchids.

You take a pinch of the product in powdered form and sprinkle it directly over the seeds or near the roots of seedlings. 

You can also dissolve 1 teaspoon (around 2.5 – 3 grams) of the product in 1 gallon (4.5 liters) of water and use that to water your seedlings or mature plants (dosage may depend on the specific brand) once every week for at least 1-2 months.

It can also be put in a hose-end sprayer Each tablespoon of a soil inoculant product covers roughly 350 square feet of area.

If you use more than the recommended dosage, it would not burn your plant because it is not a fertilizer (except for some inoculants that may also contain plant minerals).

When to inoculate plants?

The best time to inoculate plants is before germinating the seeds so that the seedling or plant becomes inoculated as soon as possible.

Applying an inoculant to seeds allows it to start working as soon as the seed germinates.

Another good time to inoculate plants is when they’re still seedlings and during transplanting. At this point, the plants have smaller root systems that can be easily colonized by the microbes.

Applying inoculants before transplanting can also reduce the effects of transplant shock,

How to know if an inoculant is working?

There will be obvious physical signs to tell that an inoculant is working, such as bigger foliage, stronger roots, taller plants, and more blooms.

To confirm that an inoculant is working as advertised, it is advised to leave a small number of plants untreated with the inoculant to serve as a control in the comparison.

How often should I add mycorrhizae?

We recommend once a month during the growing season.

In fact, most annual plants only require one application of mycorrhizae during the first weeks of the growing season.  

Frequent applications have no negative effect on plants.

Does temperature affect inoculants?

Extreme temperatures can affect the performance of mycorrhizal fungi.

The optimal temperature range for mycorrhizae is about 64 to 77 °F (18 to 25 °C), but they can tolerate a range between 0 to 140 °F (32 to 60 °C).

Are inoculants compatible with fertilizers and fungicides?

Most soil inoculants are compatible with fertilizers, fungicides, and pesticides.

Related:

Top 3 Inoculants for Plants: More Than Just Mycorrhizae

8 Ways to Cultivate Beneficial Microbes (Effectively)

Carol loves to garden and research to help others grow their green thumb.

She is working towards her dream of living close to nature.

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