How To: Culture Lactobacillus (LAB) for Horticultural use
How To - Culture Lactobacillus for horticulture

How To: Culture Lactobacillus (LAB) for Horticultural use

Generally when it comes to bacteria and microbes we’d be referring to the aerobic type you’d hope to produce in a Compost Tea (AACT) system, the reason being that the presence of anaerobic bacteria in these systems are nearly always ‘bad news’. However there are useful anaerobes out there and it is very much worth looking in to putting them to use in your horticultural endeavours!!

Enter Lactobacillus….

Lactobacillus is a facultive anaerobe that we are generally interested in for it’s ability to ferment a wide variety of things. It is this process that makes Lactobacillus or LAB the cornerstone of a range of processes the savvy gardener will find extremely useful. I’ll mention more about that later in this piece and in further blogs, but lets show you how to culture your own Lactobacillus first….

Step 1 – Rice wash

Technically you can use any reasonable carbohydrate source (preferably not simple sugars) but in this instance we’ll go with a Rice wash – I will be trying other more exciting things in the future, but until then…..
Well the title says it all really, wash some rice and collect the water. This milky wash will now contain some of the starches from the rice and provide a food source for your bacteria.

Step 2 – Collect your initial culture

Place your rice wash in a suitable vessel (a jar…) and protect the neck with some kind of net to stop anything random getting in. Ideally you’ll want to place this outside, in a garden, on a balcony ect away from the elements but open to the air. This will allow the bacteria to go to work on the wash. A day or so should be fine. You will notice a change in the wash as the bacteria start to work, it will start to smell slightly sour and three distinct layers should be visible. You now need to collect the middle of these layers – the best way is with a siphon, but a syringe or whatever you have to hand will work – just try not to disrupt the layers.

Step 3 – Feed the LAB

Now  it’s time to culture just the LAB that are present and nothing else. To do this we add milk to the liquid we collected at about 10:1, so for every 10ml of liquid you want to add 100ml of milk – You can use pretty much any milk as it’s the LAB in the wash we are culturing, however the least adulterated milk you can get your hands on the better. It’s probably worth saying you can’t use a lactose free milk for fairly obvious reasons….Finally we want to store this in an anaerobic state, so you have a few options – Ideally you can use a container with an airlock – the same as homebrewers use (or make one), you could use a bottle or jar and release the pressure every so often (not the best plan) or as I have use a heavy lid with a seal so any gas can escape but will then re-seal (not ideal to be honest….go buy some airlocks, you’ll want them for further projects!)

Step 4 – Prep & Store the LAB

After about a week you should notice a distinct change – You’ll have a layer of curds and a liquid layer – whey. It’s this liquid layer we want. Nothing too stressful here, just use a sieve and collect the liquid in a vessel – The curds can be put on the compost or whatever, it will be a great addition. Again your brew should smell sour (actually quite pleasant if you’re in to sour beers at all….) but not rancid, if it is bin it.
OK, now you have your liquid you have 2 options, store it in the fridge where it will keep for about a week or mix it with Molasses to stabilise the culture where it will keep for 6 months or more. To stabilise mix the culture 1:1 with molasses, so 1 litre culture to 1 Litre of Molasses gives you 2 Litres…’s worth airlocking this too until the mix stabilises.

What’s the point?

Excellent question :o)
The more mundane uses for LAB include using it as an odour neutraliser if you happen to keep chickens etc – Mix 30ml per litre of water and spray around the coop to reduce the smell – Unblock drains – 15ml per litre and let it go to work over night and many more!

For your growing needs however mix 30ml or so with every litre of your plant’s water. The microbes will help cycle the nutrients in the soil making them more available to the plant!
Add your LAB to compost – 30ml per litre and damp down every time you add to the pile or as you’re layering up. The Lactobacillus will speed up decomposition and start to cycle the nutrients!

Finally (and more excitingly), I mentioned earlier that LAB is the cornerstone of further processes that are highly beneficial to a gardener. For instance LAB can be used for Bokashi composting, no more need to buy bran for your indoor composting! If you’ve never heard of Bokashi, I’ll cover it at some point.
LAB can also be used to ferment plant material, for instance if you already add seaweed meal to your feeding regime, imagine if you could ‘pre-digest’ the nutrients held within the seaweed – making the non soluble elements readily available at application….with LAB you can.
If you’re a gardener familiar with the process of rotting comfrey or nettles in a bucket to annoy your plot mates, why not use LAB to break down the vegetable matter without the smell, and more importantly, without the risk of culturing the bad anaerobic bacteria.
Using these principles it’s basically possible to make your own organic liquid plant food for free and without losing friends or neighbours…..
The last point for this post is probably my favourite – With LAB it’s possible to create your own fish fertiliser (Fish hydrolysate) this in conjunction with your nettle/seaweed/comfrey/grass brews will give you the perfect base for making your own liquid organic fertiliser….

…that’s not bad for a little milk and help from a bacterium.

Foot notes – There should really be a sequence of pictures to go with this post, but frankly they weren’t up to scratch. I’ll re-do them and possibly put together a video to go with the text. If anything needs clearing up drop me an email or comment below.
– N.D

This Post Has 24 Comments

  1. Very helpfull post.Have already been using your Bactorr and wormcast in compost teas with great success. Now i can make some fermented botanical teas aswell. Thanks

  2. Love this. Ive been buying-in food for many years. Im 4 days into LAB cultivation process. 1:10 mix with milk, looking forward to seeing some curds.

    Wondering if the 30ml LAB (when added to regular feed) would work in coco coir as it does in soil?

  3. There is no need for an air lock since LAB is faculative. Yogurt, for example, is made without an airlock.

    Also, in warmer weather, the curds will often separate from the whey within a day or two.

    Finally. Unstablized whey will last in the refrigerator for months, as long as all the curds are filtered out (use a coffee filter to filter them out). You can add few table spoons of molasses to it, and refrigerate it, and will last for at least 6 months.

  4. Is there a commercially viable alternative to making LAB? If I wanted to make that fish fertilizer, for example, what can I substitute for the LAB, without another science project?

    I have a freezer full of fish that’s about to go bad, and I don’t have time to wait to brew this.

    1. Ancient Chinese secret Find a pet order eliminator at ace or whatever. It has bacillus and other bennies in it. Look on the label to get the right one it’s organic. Mix that with the fish and brown sugar or molasses I don’t use the milk step but I’m gonna try it in the future. Been working for me my way. You could let your fish rot in a bucket if you run out of time. The micros will be living still. Just made a fermented yard manure type tea.
      Chicken manure coffe grinds egg shells whole fish and the pet odor spray. Used Foliar spray on yellow leaves turned green over night.

      1. Yes! They’re made in a similar way. You can use lactobacillus to eliminate odours too 🙂
        My two best examples are cleaning up after forgetting about a cabbage in the corner of the workshop and fermenting a carrot and cucumber feed in the office with no smell. Also great if you want to make comfrey tea on the allotment without smelling like a hero 🙂

  5. I just siphoned off my lactic acid and put it in another container with equal parts molasses and put an airlock on top. Should I let it stabilize at room temperature and about how long does this normally take?

  6. Hi!
    If I want to make a fermented extract of neetles, 1 kg neetle and 10 liters water. How many milliliters of LAB should I put in it?

    1. Hi Bernie, I’d say about 30ml per kilo of plant material, with enough water to just cover the nettles.
      You can add more after.
      Fermented Plant Juice article here

      1. Thanks Nigel!

  7. Hi I’m wanting to try this on a crop of sugarcane by injecting it into the soil while applying fertilizer. How much LAB should I use per hectare and how much water do I mix with it?

    1. Great question. I don’t know for farm scale. I’m sure a Korean Natural Farming resource would have the answer though Dylan.

  8. Hi. Instead of using a rice wash to produce LAB, what about using the whey from strained live yogurt?

    1. You’d have to give it a go! I presume you’re thinking of adding the milk back to the whey?
      Another idea would be to cut some of the whey with a little rice wash to feed it up, but continuing the culture….

      Give it a go and let us know how you got on!!

      1. Once I’ve made whey the remaining milk is in the form of curd, so I can’t add it back (it’s good breakfast food), but I can add fresh milk to the whey. I’ll do that for my greenhouse tomatoes, one of which just got the pip, as my ma would have said, collapsed completely over 24 hours and had to be removed. I immediately dumped some yoghurt on the place where it had been. Now have made some whey by warming some lightly pasteurised milk that was starting to turn, adding yoghurt and rennet to it, and keeping it warm for a few hours, straining it through several layers of muslin. Will add fresh milk and spray that on the undersides of the leaves of the remaining tomatoes. Thanks for being there.

  9. First of all , thank you very very much for letting this known to the world. I have a question. If I already have curd(home made from cow’s milk and little curd starter culture) which I use for everyday food, can I ferment it anaerobically for a week and sieve? Would you think this will work?

    1. I believe it will, however the starter culture will likely have a limited number of specific species.
      If you were to use this method “as-is” you will potentially get a more diverse culture

      1. Yes you make a lot sense. Tomorrow I’m getting my rice wash . There are few other beneficial anaerobic bacteria in the commercial EM. You have any experiments to culture those . With AACT, aerobic bacteria and fungi are doing okay. How will I get more anaerobic stuffs.

        1. Unless you add some commercial EM to your labs it’s a bit difficult to know exactly what you’re getting. But if you make good labs from different areas you can experiment at least.
          For me it’s mostly about experimenting, trying new things and testing. That’s half (maybe even ALL) the fun 🙂

  10. Hi, i have mixed in 120 litres carrel with ainairlock 55 and 55 liters of each.. molasses and labs from the cheese factory where they used a starter, i added some turba, ash, silts and bone meal. After fermenting it satarted to leave some funny smell with sulfidric acid.. after 8 days opened and the smell and the gas was clearly like rotting eggs.. i have another culture of labs plus bread yeast which smells so nice to see if they get rid of the stink.. any suggestions as to why that would be? Any microbes from turba( peatmoss)..or silts..?.

    1. Silts (in-particular) can contain many different types of microbes – some will be sulphur producing. I would guess this is the problem.
      Take a look at the Winogradsky column – you are likely re-creating some of these conditions in your mix.

  11. Hi there .

    How would i go about using LAB in hydroponics . I dont want to spend on a chiller so i keep getting pythium .

    1. It depends on your system. I believe Sub-irrigation planters (SIPS) are quite well suited to labs.
      But your average “Hydroponics” system is likely to be aerobic – So I would look more towards Aerobic bacteria and fungi
      Like Bactorr, Mycorr, Tricorr etc
      Ultimately improving your environment is the way to go – maybe look at other ways to cool the rootzone?

  12. Hydroton, the red clay pebbles, Made in kilnsm German, with a stone w/aerator pump water is 7 gallons, Is that aneorobic? Is anoerobic the sulfer stuff, and is it you right add Molasses and that causes fermentngf and that the smell get better after the sugar is added?

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