My Favourite Biological Brew

bed of spring salads at edible backyard

The health of all life above ground – you, me and our crops included, rests on the shoulders of the trillions of tiny organisms – the bacteria, fungi, protozoa, nematodes et all that inhabit healthy soil. These microscopic critters are in constant motion performing checks and balances that counteract our often diabolical actions and restore equanimity and bring best health. You cant see them but you see their handiwork in the health of your crops. They are the key to an abundant garden.

leaf mulch in the winter greenhouse
Leaf mulch

Create the ideal habitat for soil life with natural, simple soil kai like compost, seaweed, leaves, green waste and rotted manure. Soil knows and understands these things – they’ve been working together a long time aye. Keep the soil covered in either plants or mulch, water wisely and plant in guilds.

There after, put the cherry on top with a monthly biological feed to keep the life humming above and below ground for strong growth and immunity. Biological life is the perfect antidote to pesticides, herbicides and pollution. Lets bring it – less killing and more life!

Here’s my favourite 2 ingredient, biological brew.

Make it

Em molasses and fish to make a biological brew for the soil

Half fill your watering can or sprayer with water then add in one biological ingredient + one packed lunch from the lists below. Dilute each to the recommended rates then top up with water. This mixes the feed through the water better than adding it first or last.

  1. EM Garden 1 or homemade activated compost tea are liquid biological brews full of beneficial fungi, bacteria, yeasts and actinomycetes – all the good guys. Use one or the other you don’t need both.
  2. Send this living liquid out into your garden with a packed lunch to kick start it. Add either worm wees or liquid seaweed or liquid fish or molasses.
  3. Neem is an optional third addition if sucking pests populations are booming.

(I’d love to claim the phrase “packed lunch”, but they’re Cherryle Prews words, not mine.)

Use it

liquid feeding the vegetable garden with a biological brew

This one brew does everything – vegetables, fruits, roses and pasture.


Spray or pour over all your edible crops, once a month as maintenance to keep everyone in good heart. Foliage, leaves, bark – the lot! Spray in the cool of the evening or early morning. If you’ve added Neem, you’ll need to do an evening spray.

Biology slows right down in the cold, so if plant growth comes to a standstill at your place in winter – when soil temps dip below 10°C, stop with the biological sprays until things warm up again and get moving.


You can use this brew more often – as much as weekly, when pressure of one kind or another is high. For example in new gardens, in the greenhouse during the peak summer, on any crops burdened by disease or pest, where soil is tired, weather is far from ideal or weed pressure is through the roof.


Pour on newly made compost and kick start new crops by saturating the soil with it pre planting.

Biological brews are the perfect weekly booster during autumn for strong growth before soil cools.


  1. Garth Guptill says

    Kath can we use borage in the same manner as we do for Comfrey… as a liquid fertiliser…
    I also make my own liquid seaweed but I’m unsure of what strength I should put it on at,any ideas,cheers Garth Guptill

    • Oh yes to borage – go for a mix of mineral rich herbs – eg yarrow, comfrey, borage, parsley. As for seaweed, dilute to the colour of weak tea is best, ratios only work where production is standardised. Less is more in the case of liquid feed. The power is in the regular usage. Enjoy! Kath

  2. Christine Koeleman says

    Katch, have you ever used rue in your brew? I have this herb in my garden and the smell is just awful. It stays with you for a long time. I understand it is an insect repellent. You use neem in the soil. I have grapes in a glasshouse (they won’t grow outside with a huge amount of fungicides) and I have a HUGE problem with mealy bugs in my glasshouse. I have used everything, from soap, pyrethrin, oils, neem, alcohol, garlic, chili, but nothing works except picking them off by hand. I thought a rue treatment might help, or have a rue plant in the glasshouse. Maybe I should water the roots with neem. What are your thoughts? Many thanks for your blog, It is so good to see how you get the most out of your garden and how your share all your knowledge with us.

    • Hey Christine, I have good news for you – my advise is to eschew the sprays and focus on beneficial insect control. Epidemics of pests are best managed by calling in the predators – in this case mealy bug ladybird, steely blue ladybird and parasitic wasps – there are heaps which is good news. It takes courage to let the pest go in the beginning but is so very thrilling once it starts to work. Do you have plenty of fodder in the greenhouse for beneficials? Check in with the health of your soil – what are you feeding your plants? Over feeding, over or under watering and artificial fertiliser all contribute to sucking insects. This tag team of soil health and beneficial insect power is the ultimate and will in the future have you relaxing back into paradise with less and less insect issues as the years roll on. Keep handpicking but leaving most about will encourage the predators. Dont spray – no herbicide around the edges outside etc spray will put the beneficials right off. Basically follow along as per this article – Enjoy!

  3. Christine Koeleman says

    Hi Kath, thanks for your reply. I looked at it a week or 2 ago. To buy mealy bug lady bird cost me 15 dollar +GST for 10. I was thinking, they will fly out of my glass house in no time. I can open the door in the hope they come in? I did not see that one in my garden when I tried to look for them. I have heaps of flax also covered with mealy bug. The steely blue one I find in my garden on citrus. I can give it a go and move them actively in the glasshouse. The surrounding area have heaps of beneficial plants (vegetable plot). There are no beneficial plants in the glasshouse. It is a grape only. I can grow something underneath, that might be worth trying. It might be nasturtium and leave the door open? Do you have a suggestion what to grow underneath? Many thanks, you just gave me the nudge to try and give it a go.

    • beneficial insects will come of their own accord if you provide the right environment and ongoing food for them. Focus on this first and soil health. I cannot emphasise soil health enough here. Weekly biological sprays will boost plants at a cellular level making all the difference to pest levels – more so than insecticides – it doesn’t happen over night but eventually instead of drowning in them they abate. In the article I sent you theres is a link to beneficial plants also use the search bar on my website and put greenhouse in. Google up mealy bug predators also to learn specific food. This approach will bring you long term solution otherwise you’ll be ‘fighting’ them forever. There is a period in the beginning where its hard to keep going as you await the arrival of the benies but they will come when all conditions align. Putting them there wont cut it if theres no food available – they’ll leave. Love to hear how you get on.

  4. Christine Koeleman says

    Okay, thanks. Let’s open up the doors and see what comes in. I don’t fertilise the grape plant. There is a layer of mulch and a sprinkle of water on a timer. The plant is very healthy, and I have to prune lots out. The mealy bugs are brought in by ants I suspect. Let start by doing this and adding some other beneficial plants.