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The Miracle of Microbes!

The Miracle of Microbes!

Alex Grady

It’s easy to fear microbes. With the threat of bud rot, root rot and powdery mildew, it’s tempting to just sterilise everything!

Don’t do that! Here's why.

Plants have evolved to work alongside microbes to gain greater access to nutrients and fight off pathogens. Microbes even help improve quality and yield.

In Nature

In the great outdoors, plants depend on microbes.

In woodlands and forests, plants are surrounded by fungi, bacteria and other microbes that feed on organic matter - like leaves, sticks, dead insects and animals.

Doing this produces plant available nutrients – a process called mineralisation. Without this, plants wouldn’t survive.

In Nature

How To Use Microbes Indoors

Whatever your media, there'll be some microbial activity in your root zone, even if it’s not intentional.

After all, the microbes that flourish in natural soils are well suited to indoor potting soils, coco and even hydro systems. All you need to do is encourage their growth to ward off pathogens and improve plant growth. It’s a no-brainer.

The ‘beneficial microbes’ you need to think about fall into 3 groups; ‘bacteria’, ‘fungi’ and ‘mycorrhizal fungi’.


Bacteria are often the most dominant organisms around roots.

In a single gram of healthy soil, you’ll find around 40 million bacteria! Mind boggling, right?

Bacteria are so important that plants deliberately attract them with sugars.

When given simple sugars, bacteria grow and divide rapidly. So, plants produce sugars through photosynthesis, then push them out of roots as a sugary solution called ‘root exudates’.

This draws bacteria to roots.

Most are free-living, so can function in soil with or without plants. However, some only function when very close to plants roots.



As mentioned earlier, some bacteria feed on organic matter and convert it to plant available nutrients – this is called mineralisation.

You’ll find this type of bacteria in:

Azotobacter and Azospirillum

These types of bacteria convert nitrogen from the air into a form that the plants can use. You’ll find them in:


These are a group of bacteria that are great for degrading complex organic matter, pathogen control and keeping the rootzone healthy.

  • Mammoth P contains Pseudomonas putida and a few other species

Mammoth P, cleverly uses Pseudomonas putida to improve the availability and uptake of Phosphorus, which is key to plant growth, root growth and flower formation.

Regular use has been shown to dramatically increase yield by up to 16%.

Bacillus subtilis

This is another common species, which is mainly involved in pathogen control.

There are plenty of other Bacillus species with an array of uses – like making locked up nutrients soluble.

Plant Growth Promoting Rhizo-bacteria (PGPR)

These bacteria are known to produce hormone-like compounds that improve plant growth.

They can be found in:


Fungi are also very common in outdoor soils. But they’re slow to grow, so it’s a bit trickier to get high fungal numbers indoors.

Saprophytic fungi

These fungi help keep soil moist and support the growth of bacteria.

They grow root-like threads through the soil (called hyphae) and produce enzymes to degrade organic material.

These fungi are free-living, so can grow without being close to plant roots.

Saprophytic fungi


You must’ve heard of Trichoderma! It’s a fungal inoculant that lots of growers swear by!

This type of fungi is a furious pathogen hunter that’ll feed on pathogenic fungi. Use it regularly and you’ll really reduce the risk of fungal pathogens - like Fusarium and Pythium.

Products with Trichoderma include:

Mycorrhizal Fungi

Last (definitely not least!) in our list are the mycorrhizal fungi.

These clever microbes feed water and nutrients directly into your plant.

To do this, the fungi attaches to roots. They actually penetrate (and grow inside) root tissue, forming exchange sites – known as vesicles.

Outside of roots, they grow very fine fungal threads (hyphae). These tiny threads can access pores in soil that roots are too big to reach. The threads then transport water and nutrients absorbed (mainly P) into your plant. In return, your plant feeds the fungus sugars.

The result is a plant with far more access to the water and nutrients in your growing media.

Mycorrhizal Fungi

It does take time for mycorrhizae (the name for the relationship between the plants and fungus) to form. In some cases, it can be up to 6 weeks!

So, make sure you apply as early as possible. Products containing mycorrhizal fungi include:

Which Product To Use and When?

Most growers start in propagation, where microbes help create a strong and healthy root system.

Here’s how and when to use our bestselling beneficials.

Ecothrive Biosys

  • Add the powder to water to make a microbial tea
  • Use in propagation to soak plugs (jiffy’s, root riots and rockwool) and for watering cuttings and small pots
  • Use through veg and early flowering every 1-2 weeks by watering in to ensure a healthy microbial population
Ecothrive Biosys

Xtreme Mykos

  • Use to dust the roots of cuttings and seedlings when potting up
  • Dust the root balls when transplanting

Great White Mycorrhizae

  • Dust the root balls when transplanting

  • Use to dust onto the roots of cuttings and seedlings when potting up

  • You can also add to water and apply to the root zone every 1-2 weeks

Ecothrive Charge

  • Apply as potting mix at 1 – 2L / 50L of media
  • Water in plants at 90ml – 180ml/L of water
  • Apply top dressing roughly every 4 weeks (20 – 40ml per 10L pot)
  • Foliar spray at rate of 1 – 2g per L of water

Mammoth P

  • Use from 0.16ml -0.26ml L (propagation & veg), 0.4ml – 1.06ml/L (flowering) and 0.26ml/L (flush)

Guard ‘n’ Aid Healthy Root

  • Soak rockwool cubes at 3ml/L

  • Apply with every nutrient change or media flush at 3ml/L (soil) 25ml/40L (hydro) or 5ml/L (maturing plants)

Great White Mycorrhizae

  • Apply roughly 1 scoop per gallon of water (hydro)

  • Mix 1 scoop with 2 gallons of water (media)

Guanokalong Bat Guano

  • Mix 1kg of Guanokalong with 100 – 200L of media (week 1)

  • Water in 100g per plant (top dressings)

  • Add 100g per 15L pot (transplanting)

  • To reuse soil, mix 400g with 50L of soil or coco

Top Tips

  1. Always use dechlorinated water when using beneficial microbial products
  2. Use slightly less nutrient - microbes help feed plants, and too much nutrient will make them go dormant
  3. Use microbes as early as possible in your grow

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