Compost bin/Worm farm in a bath tub.

Discussion in 'Building DIY, Machinery & Tools' started by ClissAT, Aug 10, 2017.

  1. ClissAT

    ClissAT Valued Member Premium Member GOLD

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    My compost bin is working really well & I am harvesting compost for my container garden top ups already.
    So far I am not harvesting worms although I'm sure there are some ending up in the compost I take out.
    They are working really hard turning litres of F&V scraps into compost in a matter of days.

    I started with the bath tub sitting up on 2 stacks of free old pavers to bring it up to my waist height so I didn't have to bend over. I half filled the tub with course cane mulch (from a bale not the stuff used to mulch pot plants & small garden beds).

    I seeded it with the last of the compost from my Mothers raised garden bed & compost bin which was thick with worms. Then added some bags of goat manure & various green waste from the garden. The tub still has it's drain pipe plughole so rodents cant get in that way but by placing a container under it, I harvest off the juices to pour onto my tomatoes which are growing in an adjacent bath tub.

    About every second day I add around 2-3lt household fruit & veg scraps (not chopped or put in the blender). I don't add all the other household organic materials that other people add like vacuum bag waste, etc...YUK!
    I don't add heaps of paper although I will add a few sheets of used kitchen paper sometimes. Once a week I sprinkle on the dried & crushed egg shells from previous weeks cooking.
    I mix the fresh scraps into the next portion of the old compost. So I am making my way from one end of the tub to the other progressively. It takes me around 6wks to work my way along & back to the beginning.

    Then to make room for the next round, I take out the oldest compost which works out to be about half the length of the tub but I leave some in the bottom ontop of the old cane mulch filler which is where the worms live.

    This gives me the room to begin adding all the new scraps. Each batch of scraps is mixed into the remains of the old compost in the bottom of the tub. I top up with a bit of blood & bone & some green or brown garden waste depending on what the compost needs to keep it in good health. Once a month I am adding a thick layer of goat manure which the worms go crazy for & turn into the lower compost layers overnight. Over that is course cane mulch or dead garden waste as an insulation layer.

    Once I get the half of the tub filled it is time to take out the second half of the tub of compost left from the last round of filling. The worms mostly live in the bottom layer of cane mulch which is nicely moist.

    After I started making the compost I soon found rats moved into the nutritious feeding resource. So I had to make a heavy wire lid that fitted neatly inside the rim of the bath tub. These photos below is the result. There is a sheet of corrugated iron as a rain cover but allows good air flow.

    I made the lid out of scraps of verandah flooring. It is a fairly heavy untreated old hardwood that is dressed all around & painted with a stain & weatherproofing.

    I used my old shade house potting table which was around the right size to square up a template on, so my lid would fit properly into the top of the tub. Luckily I have a big old steel workers metal square so the process was easy.

    I used 10mm square wire netting which I also know of as Budgie or Bird Cage Wire. It came in 60cm wide rolls & I had a few scrap pieces which I just overlapped rather than cut when I screwed it to the under side of the lid frame.

    All screw holes had to be clamped, predrilled & countersunk to prevent cracking of the wood. I was lucky enough to find screws just the right length so their sharp little points didn't stick out the under side.

    compost bin rodent lid.jpg

    compost bin & rodent exclusion lid.jpg
     
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  2. Steve

    Steve Valued Member Premium Member GOLD

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    I like it @ClissAT. It's a good idea to use the bath tub.
    Hmm I wonder if the wife will let me use our brand new tub.....:clip:
     
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  3. stevo

    stevo Backyard Farmer Premium Member

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    Looks good Clissa, does it work ok?
    I'm wondering, most compost bins we see are sealed, covered or closed in. I assume to retain moisture.
     
  4. ClissAT

    ClissAT Valued Member Premium Member GOLD

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    Yes Stevo it does work remarkably well.

    The tub is up off the ground so air moves under it cooling it somewhat & the plug hole still has its fitting so nothing other than ants can get up the pipe into the compost but it lets out any excess moisture which drips into a bucket.

    On top of the compost I have 2 layers of hay, the first is fine aged & crisp lucerne straight off old bales left out in the sun that crumbles to very fine fragments which the worms love & the second is a layer of very course dead leaves. The only purpose for the leaves is to exclude some light & insulate the top of the compost from the radiated heat off the sheet of corrugated iron I use as a lid. If I used a lid made from some insulated refrigeration panel for example, I wouldn't need that second layer but I wouldn't have such easy air flow enabled by the corrugations.

    In summer I may find there is too much heat coming off that iron so I will have to cover the iron with hessian bags or other such material but not down the sides which would prevent the air flow under the iron across the top of the compost.

    In my experience it is the sealing off of the compost using bags that can cause it to go sour. It needs to breathe. The bags placed immediately in top of the compost are supposed to allow it to breathe but often that doesn't happen enough.

    Yesterday I took out 10lt compost but because there were so many worms, I struggled to get them to move elsewhere in the tub. I didn't want so many worms in the compost I used to plant a tree. These are compost worms not ordinary earth worms so they'll die once their ready source of food is eaten. Better that they stay in the good stuff.

    There is a process of baiting them to move along in the tub by clearing the surface of the area you want to harvest from, then placing fresh 'food' in another place to get the worms to move away from the compost you want to harvest.

    However, I think mine has already reached a point where I have to duplicate the system & hive off half the worms because there are just too many worms in the given volume of the tub. Also I need to fluff up the bottom layer where the cane mulch was because new cane mulch needs to be added before summer to allow better drainage & living conditions for the worms. Its during that process that hiving off is easiest.

    But I really don't need 2 complete worm farms. Anyone want half my worms?:idea:
     
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  5. Ash

    Ash Valued Member Premium Member GOLD

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    That's a lot of worms! Just doing it with one small worm farm and it's enough for us to manage feeding them and watering them. What a set up you've got!
     
  6. ClissAT

    ClissAT Valued Member Premium Member GOLD

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    thanks Ash :D

    I harvested off another 20lt of compost on Thursday last, then replaced new cane mulch in the bottom of a third of the length of the tub before placing the worms back ontop of that mulch ready for a new round of scraps. They seem happy enough with that setup!:)
     
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