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Hi Edd, when you say ready for harvesting what do you mean? How do you separate the compost from the worms?
This is the difficult part Ashleigh. I have several methods depending on how much compost i have.
The one i use the most is called the light method. I tip the compost onto a table i have outside and pile it into a cone shape. (just a pile really) Then i leave it for 1/2 hour in the bright light so the worms move to the bottom of the pile in the middle. They hate sunlight and try to get as far away as possible, into the dark. Then you just scoop of the top and leave for a while and keep doing this until you are left with a ball of wriggling worms to put back into the new bed. You can do this in a garage with a bright spot light.
I will get some pics for the barrel method that i use when there is a larger amount of compost to be sieved.
DIY worm harvester. There are several different system but this one is the best and the one i use.
The plans are here. courtesy of Washington State University website.(freely) available
I really want to have a go at this, if you keep your container outside how much longer does it take compared to indoors?
The temperature indoors is constant so they are happy all year. Once the temperature outside gets to about 12 degrees everything speeds up dramatically. It all depends on the amount of worms and if they are happy with the conditions they are in. If they think there is enough food then they will reproduce at a astounding rate. Each worm can produce its own body weight in compost each day, in the right conditions.
I artificially raise the temperature of my outside bins by adding lots more coffee grounds as they heat up.
Thank you, Edd. Lots of info there.
Let me know how you get on after you have mixed in the new bedding materials, please.
Separating worms from casts. Continued.
Most composting worms will not move away from the finished compost immediately unless you entice them to (although Eisenia Fetida are more likely to roam around). Slowly through time, the worms will move out to look for more food, but this can take many months.
It is really hard to create a 100% worm free worm cast product because there will always be some baby worms you will have missed out, or cocoons where new worms will hatch out from in the future. However there are effective ways to remove most of the worms from the compost to give you a good quality final product (and you will want as many worms back to start your next batch of vermicomposting).
Having a small number of worms in your final worm compost is not a problem at all!
In fact if you spread some of the worms with the worm cast in your garden it will be a bonus for your garden soil. Composting worms will not survive for very long if there is not a lot of dead organic matter around the surface, but for the time it is there it can help aerate the surface of the soil and continuingly add fresh worm cast in to the surround garden soil.
You can use food to entice the worms to move, and this can be done in two ways.
The first way is horizontal separation. This will be the best way to separate worms if your worm system is a simple tub or box. Imagine splitting your worm box in half down the centre. Feed on one half of the worm box only and leave the other half to rest. Very soon the worms will all migrate to the half with food leaving the other half without food to mature and harvest. Now once the other half is ready for harvest, swap the halves and repeat the process.
The other way is vertical separation, and is used for vertical stacking wormery systems.
These are boxes with perforated bottom trays which stacks on top of each other. As one tray is finished with the composting process, you will need to add another tray on top filled with food and new bedding. The worms naturally migrate upwards looking for food, and will crawl up through the perforated base into the new tray, leaving in the old tray harvestable cast free from worms.
Another method to separate worms from cast is to use the light method as I have mentioned in my previous. This is also a great method to use to further separate any worms which may still be in the cast after vertical or horizontal separation.
Worms are sensitive to light and will try its best to get away from it.
Grabbing a handful of the cast, create a pile on a covered surface and use a lamp to shine on to the cast pile or just use bright sunlight. Any worms will start burrowing down to the lower surface. You can now remove the top surface of the cast pile revealing the worms. With the detection of light, the worms will again burrow further down the pile allowing you to remove another surface of pure cast.
Repeat this process until you end up with a ball of worms.
You have successfully separated your worms from your cast!
Just to clarify, worm bin reservoirs catch what’s known as ‘leachate’ – basically liquid (mostly water) that has drained down through the worm bed. Some mistakenly refer to this liquid as ‘worm tea’, and while it CAN be used in this manner (best if diluted though), it is definitely not as high quality as genuine worm tea. The best way to make worm tea is to soak high quality worm castings in aerated water. I will go into greater depth on producing worm tea later .