Worm Farm Series – Part 6 – Harvesting Your Vermicast (And Worms)


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This is the sixth and final article in our Worm Farm Series. Throughout the series we’ve covered all the basics of worm farming along the way so, if you missed any of the previous parts of this series, check them out below:

Part One – The Benefits Of A Worm Farm
Part Two – Setting Up Your Worm Farm
Part Three – Moving In Time
Part Four – Feeding Your Worms
Part Five – Maintaining Your Worm Farm

With your worm farm busy processing your organic waste, there’s going to come a time when you can finally reap the rewards of all the hard work your worms have been doing, and you can start harvesting the vermicast that has been created in your worm farm.

What Is Vermicast?

Vermicast is a wonderful, nutrient rich and beneficial fertiliser that is created as a by product of the activity in your worm farm. It’s a big part of the reason gardeners decide to set up a worm farm, as well as the added benefit of easily getting rid of organic waste.

Vermicast is essentially the droppings of the worms, excreted as they eat their way through your organic waste.

When you have a happy healthy worm farm your worms will produce a dark, soil like vermicast that you can then harvest and use in your garden to condition your soil, or fertilise your plants.

harvesting vermicast

How To Harvest Your Vermicast

How you’ll harvest your vermicast depends on the type of worm farm you have.

Some farms, like the Hungry Bin or the Can O Worms worm farm, are designed so that the worms slowly move their way up through the farm, away from the vermicast towards the fresh food, leaving a bin or section of the worm farm with just the castings ready to harvest.

Generally with these worm farms you either release the bottom of the bin and let the castings fall out or you remove the lower bin where the processed castings have been left and let the worms continue their way up through the upper bins.

Single bin worm farms can take a bit more work to harvest.

With these worm farms you’ll still have the worms working their way up through the bin (from the bottom to the top) for the fresher food, which means that your castings will all be at the bottom of the bin and you need to remove all the fresh food and worms from the top of the bin first so that you can get to the castings.

To harvest your castings you’ll need to prepare an area to separate the vermicast from the rest of your bin.

Then there are a number of ways to separate the castings from the unprocessed waste, and the worms.

Bin Shuffle

A quick way to move your unprocessed waste and get to your vermicast is to start up another worm farm bin that you can transfer all the ‘working’ material to, digging your current bin out until you reach the castings.

By removing the top, unprocessed layers of the bin (along with worms), you essentially set the worms up in their new home and then have access to the castings they have left behind.

Just make sure to lay some new bedding down before you do the move.

If you don’t have a spare worm farm, you can lay out a tarpaulin or large plastic bins and take out the top material, then reintroduce it your worm farm once you have removed all the castings.


Another way to harvest your vermicast which can speed things up is to use a soil sifter.

A sifter can be made with a simple timber frame and a small grade wire mesh. Small amounts of the vermicast are then put into the sifter and as you shake out the fine worm castings, you are left with any unprocessed organic waste and any stray worms on the sifter.


You can also take advantage of the worms natural desire to migrate towards a new food source. This is a similar concept to how the tiered worm farms work, but in a single bin (if you have enough room) you can start to supply just one side of the farm with food, and leave the other side to finish processing. Once the worms have completed their work on one side of the bin, they will naturally move across to the other side of the bin where you are supplying fresh food, leaving the vermicast on one side of the bin, ready to be harvested.

Save Your Strays

Regardless of which type of worm farm you have, when you remove the castings you’ll likely find a few worms left behind.

It’s really simple to extract these strays so you can put them back into your worm farm. Simply spread out your castings on a tarpaulin or a plastic lid, somewhere in bright sunlight. The stray worms will retreat away from the light, deeper into the castings. When they have, the top layer of castings can be removed worm free. Continue to take off the top layer until you have just a thin layer of castings and all the worms collected together at the bottom.

Then just drop your worms back into their home so they can keep working!

Harvesting Your Worms

If your worm farm is working well, you may find you soon have an over abundance of worms.

You can use these to either start an additional worm farm, or you can sell them or share them with others.

To harvest your worms you basically follow a similar process to the way you remove stray worms from your vermicast.

First dig out a portion of the working area of your farm, choosing an area where the food is being processed and the worms are happily doing their thing.

Lay this portion out on a tarpaulin or plastic lid, in the sunlight. Again, the worms will retreat away from the light, into the depths of the material you’ve dug out. Remove a layer at a time from the top of the pile until you end up with just a thin layer of waste and the collected worms. Obviously you don’t need to fuss too much about removing every last bit of organic waste as the worms will appreciate being left with something to keep munching on when you give them away or introduce them to your new worm farm.

Well, we’ve reached the end of our Worm Farm Series. With the last 6 articles you should have a pretty good understanding of how to set up, maintain and harvest from your worm farm. BUT, if you haven’t had every question you have answered, then just ask via the comments section below each installment of the series and I will do my best to help you out : )

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4 thoughts on “Worm Farm Series – Part 6 – Harvesting Your Vermicast (And Worms)”

  1. Given the worm farms are above ground, can the worms survive freezing temperatures during the winter? If not, how does one protect them from freezing? Thanks.

    • Thanks for your question 🙂 Even in a raised farm the worms will burrow right into the warmest parts of the farm to survive, but it’s still a good idea to insulate your worms against freezing temperatures if you can. One way to do this, and the method we use, is to wrap the bin in either an old blanket, bubble wrap or some other insulating product. Keep them wrapped until those frosty nights have passed but also take the insulation off during warmer days to let the farm warm naturally when it can. Hope this helps.

  2. Hi there
    A few weeks ago our worms produced 18 litres of fertiliser one morning (when it was snowing).
    Since that extravagance it has been varied in amount and colour. Is the darker stuff better than the light?
    And why the sudden production rush? Also we have more in winter than the other seasons.

    Thanks for your time

    • Hi Leslie

      Is there any snow melt/rain getting into the farm? 18 litres is definitely a lot for one morning so it sounds more like it was ‘dirty’ water than actual worm tea. You’re right in assuming that the darker tea is better than the light, and if it’s worm tea you’re getting it should be darker. Don’t worry though, the lighter run off will still have some nutritional value so certainly add it to your garden.


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