Everything You Need to Know About MO Bacter For moss & lawns

Written by Daniel Woodley. Reviewed by Elizabeth Smith. Published to Lawn Care on: 24th March 2023.

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Who Should Use Mo Bacter?

Any gardener who has moss in their lawns can use MO Bacter but it’s particularly useful for those who:

• Don’t want to rake out or scarify the dead moss (MO Bacter breaks it down into nutrients for the lawn).
• Are organic gardeners who want to reduce their usage of harsh chemicals.
• Have pets and children that use the lawn.
• Have a patio that could be stained by iron sulphate (a popular alternative moss killer).

Who Shouldn’t Rely on Mo Bacter?

I’ve used MO Bacter in my own garden and in a professional capacity for past customers and the results have always met my expectation, but it’s not for everyone.

Here are a few drawbacks I’ve discovered:

• I’ve found that it takes weeks for the bacteria in MO Bacter to break down the moss and turn it into nutrients, so it’s not the best option for those that want quick results.
• During my tests, I noticed that it worked best when the lawn was kept moist, and it was less effective when I allowed the lawn to dry out.
• On heavily moss-infested lawns, I’ve discovered that it will require a second treatment after 3 months, and in such situations, I’ve found it easier and quicker to use iron sulphate and a lawn scarifier to pull out the dead moss.

Key Details

MO Bacter contains the following, derived from natural sources:

• Nitrogen 5%
• Phosphorus 5%
• Potassium 20%
• Magnesium 3%
• Added natural bacteria

Type: Granules.

Sold as: 10kg and 20kg bags.

Application method, rate and timing: MO Bacter can be applied by hand or spreader at any time between late March and late September, but I’ve found it most effective during the growing season in spring or autumn when the lawn is moist and warm but never dry, scorched or too cold (must be above 10°c). Based on my test results, one 10kg bag should cover around 60-100 square metres of lawn, depending on the amount of moss present. A 20kg bag should treat 120-200 square metres.

Longevity: Based on my experience with MO Bacter, I believe it kills the moss over several weeks, and the bacteria helps to break it down into nutrients over a 3-month period, hence why I suggest applying it twice yearly, in the spring and autumn.

Overseed: I overseeded twice, first one week after application and then again after 4 weeks. As the bacteria broke the moss down into nutrients, the grass seed fell onto the soil and germinated, but as the process was slow and erratic, many of the seeds were stolen by birds, so I had to overseed again after 4 weeks.

What’s in the Bag

Here are a few photos of MO Bacter that I took during my test of the product:

My Experience With MO Bacter

I started using MO Bacter several years ago as I have a north-facing garden that is prone to moss growth, and I was fed up with raking and scarifying the lawn, which often damaged it. As little sunlight gets into my garden, I found the grass took a long time to recover from aggressive raking and scarifying. 

I’ve also used MO Bacter in a professional capacity when I worked for a landscaping firm, and I’ve recommended it to another firm that cleared lawn moss around headstones that were at risk of damage from iron sulphate (a popular alternative).

In 2022, I tested MO Bacter on a patch of mossy lawn, here’s how I applied it and the results I saw:

1) I applied MO Bacter by hand in April, just as the temperature was warming up and there was enough moisture to keep the bacteria active.

2) By early May, some of the moss had turned a light brown colour and was thinning out, so I overseeded with a sprinkling of new grass seed for shaded gardens.

3) By June, much of the moss was gone, and the grass seed had germinated and was establishing itself well.

4) I repeated the above steps in the autumn and will probably do so each year moving forward as I have a shaded garden, and moss will always take hold if I don’t take steps to stop it.

Problems I’ve Encountered

I never encountered any issues with MO Bacter for moss control, as I’ve used it before and knew what to expect.

I can’t imagine gardeners would have any problems provided their expectations are realistic and they note:

• The ground must be moist for the bacteria to work.
• It’s slow to act.
• If your lawn is carpeted in moss, it will require a repeat application, probably yearly and maybe twice a year to get it under control to start with.

My Favourite Feature

My favourite feature of MO Bacter is the bacteria that breaks down the moss into nutrients; this means I don’t have to rake my lawn at all. I just apply the granules, keep the lawn moist and that’s it, MO Bacter does the rest.

I have a shaded garden and I’ve found that aggressive raking does more damage than good, as there isn’t enough sunlight to help the grass recover in time for summer.

Also, I like that it’s safe for pets and children.

For me, MO Bacter is a great product but whether it’s for you will depend on the condition of your lawn, what results you expect and how much time (if any) you are prepared to spend raking and scarifying.

Alternatives Products and Methods

MO Bacter does two things: 1) Kills moss. 2) Feeds the lawn.

Here are alternatives that achieve the same results:

Nearly identical products: Miracle-Gro has a similar product that does the same thing, and Vitax also sells a product with bacteria.

For moss control – I’ve used iron sulphate dozens of times on mossy lawns as it’s cheap and effective but it does turn the moss black within a week, and I’ve always had to rake out the dead moss. On larger lawns, I’ve even had to hire a lawn scarifier to pull it out, so if you have lots of moss in your lawn and you use iron sulphate, your entire lawn might look black. There are pros and cons of iron sulphate that I’ve discussed here. Beyond iron sulphate, gardeners can remove moss once or twice a year by raking and scarifying but if the lawn is in a shaded garden, it may take a while to recover.

To feed the lawn – There are dozens of lawn feeds and fertilisers on sale, and I’ve tested several of them over the years. In 2020, I used seaweed extract fertiliser exclusively on my lawn and was pleased with the results. While it doesn’t have any moss-killing properties, it greened up the grass and helped it to grow thick and lush which supressed moss growth.

Looking beyond MO Bacter and similar products, I’ve found the best way to keep a lawn looking lush and green is to:

• Apply a lawn weed killer in the spring just as the grass starts growing.
• Lightly scarify and sprinkle grass seed over the lawn in the spring.
• Feed and water regularly during the growing season.
• Apply an autumn lawn feed later in the year as part of autumn lawn care.
• Aerate the lawn once a year in the autumn with a hollow tine aerator and overseed if it’s looking patchy.

I hope you found this guide to MO Bacter helpful, I’ve been using it for several years and will continue doing so as I have a shaded garden where moss thrives.

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