6Harvest time
Your worm farm mainly provides worm wee — a nutrient-packed liquid “rocket fuel” for your garden that’s available on tap as you feed your worms. Solid worm castings can be harvested in small amounts or whenever you need to clear space for more food scraps.
Both worm wee and castings are packed with nutrients and beneficial microbes, making them a natural, zero-emissions fertiliser. Use them to boost soil health, grow strong plants, and keep your garden thriving all year round.
Worm wee is continuously collected in the pan under your worm farm. Before giving it to plants, dilute it with water about 10:1 to the colour of weak tea.
Once a tray is full of broken down food and worm castings, it's time to harvest your soil fertiliser.
Swap the trays so that the one with the most worm castings is on the top, then remove the lid and leave the tray in the sun for about an hour. The worms will burrow down into the tray underneath to avoid the light.
To get as many worms out of the castings as possible before harvest, gently scrape the worm castings to expose them to the sun, encouraging the worms to burrow deeper. You may want to remove castings one handful at a time to ensure you remove as many worms from the castings as possible. Just put the worms into the tray with food in it - it's ok if some castings go with them.
Once you have removed all worms and castings, you can store the empty tray underneath your working tray to save space. Or if the top tray is already close to three-quarters full, you can put the empty tray directly on top and start putting in food scraps.
Tips
- You can store worm wee in old glass jars or plastic containers. If you leave it in a dark, cool area, it will keep for a couple of months, although it’s always best to use it fresh.
- Spraying diluted worm wee on the leaves of plants make the leaves healthier and stronger and protects them from pests.
- You don't need to worry about emptying worm castings more than every six months or so. When you do, add some moist shredded newspaper in the new empty tray as bedding for the worms.
- Worm castings should be used soon after harvest, before they dry out.
Did you know?
You can mix your worm castings with soil in a 1:1 ratio and spread it around plants. To make potting mix, combine the castings with either soil, compost, sand or vermiculite at a ratio of 1:4, and mix well.
Note that sandy soils don't have enough structure or biology to retain many nutrients. To add structure to sandy soil, first use a large amount of compost or mulch, then combine with worm wee and castings. By doing this you'll quickly start to build up rich, dark soil.
Apartment Composting
Harvest time (worm wee): Apartments with lots of food scraps, but few plants can have more worm wee than they need. If you dilute your worm wee more than usual – to a pale yellow colour – then you can use it on most plants every water (rather than occasionally). If you still have a lot left over, you can bottle it up and give it to your participating residents, and even the ones who aren’t (as inspiration to join).
Harvest Time (castings): You can also harvest castings and provide them to residents in gift boxes to sprinkle on their indoor plants. Or simply sprinkle small amounts of castings on plants (or mix into the soil) in the common areas and watch as they blossom.
