Boost your plant and soil health: homemade LAB fertiliser
- Room to Be
- Mar 23
- 3 min read
LAB stands for Lactic Acid Bacteria and it is an amazing soil amendment; it breaks down organic matter in the soil and releases nutrients, making them more accessible for plants. This also means it works well as a compost accelerator. LAB can also be used as a foliar spray that helps make plants more resilient to disease or to help boost growth by watering around roots and stems.
It is really easy to make.
EQUIPMENT | INGREDIENTS |
1 x empty 0.5 litre jar | Week One: |
2 x empty 1 litre jars | 500g Rice |
Cloth (eg. cheesecloth, muslin, something breathable) | 1 litre rainwater / distilled water |
Elastic bands / string | Week Two: |
Big mixing bowl | 1 x pint whole milk |
Sieve and muslin cloth for lining | |
Label and pen | |
Spoon for stirring | |
turkey baster (optional) |
METHOD:
WEEK ONE:
Put the rice and the rainwater in the mixing bowl and stir until the water is powdery white.
Pour the water through a sieve into one of the empty 1 litre jars.
Cover the jar with a cloth (instead of using a lid) and secure with an elastic band or a piece of string.
Label the jar 'LAB STOCK' and include the date it was made.
Leave for ONE WEEK somewhere out of direct sunlight at room temperature.
WEEK TWO:
There should be a film of scum on the top of the water and sediment at the bottom of the jar. The liquid we want to use is the stuff in the middle. You can use a turkey baster to extract it, or simply scoop of the scum with a spoon and then carefully pour out the middle-liquid in the other 1 litre jar, being careful not to pour out the sediment with it.
This liquid or 'stock' is what contains the Lactic Acid Bacteria. It will last up to six months in the fridge in this highly concentrated state.
To turn LAB into a fertiliser for the garden we are going to add milk. How much you make very much depends on the size of your garden.
Mix the LAB stock with 1:10 ratio of stock to milk in an empty 1 litre jar.
Stir the milk and the stock.
Place a cloth over the top of the jar instead of the lid (as before) and secure with elastic band or tie with string.
Label the jar LAB STOCK 2 with date it was made.
Leave for ONE WEEK.
WEEK THREE:
The contents of the jar will have separated into three layers. Curds at the top, whey in the middle and sediment at the bottom. It is the middle liquid you want (the whey).
You can use a turkey baster to extract this liquid or alternatively sieve the contents of the jar so the curds and sediment are caught. If you line your sieve with a muslin cloth (or similar), you will achieve more purity.
Pour strained liquid into 0.5 litre jar.
Label and date the LAB SERUM. This must be used within TWO WEEKS.
Compost the curds and sediment.
USING YOUR LAB FERTILISER:
Your LAB serum is highly concentrated and MUST be diluted for use on your garden.
For watering on your beds before the beginning of the growing season. Roughly 1 teaspoon LAB per 5 litres of water is enough. Do this once a week before planting and then water plants once every two weeks around roots and stems to help boost healthy plant growth.
The same dose can be used as a foliar spray and is good for seedlings to help with disease resilience. It can also be used at the first signs of powdery mildew. If you catch this in time, the bacteria will colonise the leaves and the pathogen won't spread.
For a compost accelerator you can double this dose. On a dry day, water any new or incomplete piles with 10 litres water to 20ml LAB. You will find this will greatly enhance microbial activity.
