How to Build a Worm Farm with Polystyrene Foam Broccoli Boxes


If you’re thinking of trying out worm farming but don’t want to go out and buy a worm farm, you can always build your own DIY worm farm instead.

Construction is really easy, and only takes a few minutes, and it can all be done using recycled materials, costing nothing at all.


To build your worm farm, you’ll need the following items:

  • two polystyrene (foam) broccoli boxes with lids
  • a piece of plastic shade cloth that is longer and wider than the base of the broccoli box
  • a few newspapers to use below the bedding material and as a ‘worm blanket’ cover sheet
  • a short piece of 12mm (1/2”) black polypipe irrigation pipe or any other narrow plastic pipe around 20cm (8”) long
  • a Philips head screwdriver #1 and #2 to punch small and big holes in the polystyrene
  • some bricks or other supports to stand the worm farm on
  • a small bucket to sit under the pipe to collect the liquid
  • a coconut coir block or other suitable bedding material

Basic Worm Farm Layout

The diagram below illustrates the basic design of how the worm farm is put together, and how it works.

Worm Farm Design

Worm Farm Construction, Step by Step

The following instructions demonstrate how to build a worm farm in 11 simple steps.

  1. Take two polystyrene foam broccoli boxes with lids, put one lid aside as you’ll only need one lid.
  2. Take one box for the upper tray, and using the #2 Philips head screwdriver, punch a two row of drain holes in the bottom. Punch the holes from the outside of the box to the inside, so they’ll appear neater on the outside, as the foam breaks out a bit and looks messier on the exit side the screwdriver hole.


  3. Cut a piece of shade cloth which is both wider and longer than the inside of the upper tray foam box, and place it in the bottom, so it runs up the sides. This will prevent the bedding and worms falling through the drain holes.bbwf04
  4. Take a few whole newspapers and sit them over the shade cloth, fold and overlap them to neatly fit the bottom of the upper tray foam box.bbwf05
  5. Take the lid, and using the #1 Philips head screwdriver, punch a two row of smaller air holes in the top of the lid. Punch the holes from the outside of the lid to the inside, so they’ll appear neater on the outside, as the foam breaks out a bit and looks messier on the exit side the screwdriver hole.bbwf06
  6. Put the upper tray foam box and lid aside, the top half is now completed.
  7. Prepare your bedding material – if using a coconut coir block, soak it in a bucket of water until it is soft.
  8. Take the other foam box for the lower tray, and on one side of the lower tray foam box, make a hole level with the bottom of the box and push the short section of black 12mm irrigation polypipe into it so it extends about 5cm (2”) inside the box.bbwf07
  9. Sit the lower tray foam box on bricks or other supports so it is high enough to sit a small bucket under the drain pipe, and place the bucket underneath the drain.
  10. Sit the upper tray foam box on top of the lower one, and then pour in the coconut  coir or other bedding material. Any excess liquid will run into the lower tray and out of the drain pipe into the bucket.bbwf08
  11. Add worms to the bedding, cover the bedding with a damp newspaper ‘worm blanket’ and put the lid back on.

That’s all! Congratulations on building your own worm farm!

If you’d like to learn more about worm farming, please check out the following articles:


  1. Hello sir,
    Nice article. Just two days back I built a similar kind of worm farm with broccoli boxes and I found this article today. I didnt use a clother underneath, but teared lots of newspaper and dipped in water and squeezed excess water out and to that added little shredded cardboard and dried leaves , all dipped and drained. Also I added little compost.. Will my babies like this bedding?? I am always worried about the moisture level of my bedding. How to know if my bedding’s dampness level is correct?? Will small ants in my farm hurt the worms? Your time and help would be greatly appreciated.


    1. If you have ants in your worm farm it is an indication that it is too dry. Ants do not like high moisture levels, and prefer dry places to live.


  2. It was nice to read your article, it re-enforced that the way I am work my 2 worm farms is correct. I have to say I am pretty excited with the way the worms have multiplied and the amount of liquid gold and castings I am getting.


    1. Polystyrene (Styrofoam) is a technically expanded polystyrene foam, regular polystyrene is a common hard plastic used for CD cases and lots of plastics you find on appliances, etc. Polystyrene is a polymer of the styrene monomer, meaning styrene molecules are linked together to make polystyrene.

      While going into the technicalities of polystyrene foam toxicity is beyond the scope of this article and deserves an article of its own, I can say that Styrofoam (expanded polystyrene foam) under certain conditions leaches out styrene, a neurotoxic chemical which is also classified as a possible human carcinogen by the EPA and by the International Agency for Research on Cancer (IARC), it’s a compound that causes cancer in animals. The risk with Styrofoam is when it’s used in food containers, where it leaches out toxic styrene when in contact with hot, acidic or oily food or alcohol, causing a human health risk. Never microwave food in Styrofoam containers or eat oily food from them either, and don’t ever drink tea or coffee, fruit juice or alcoholic drinks from Styrofoam cups! Alcohol dissolves polystyrene foam to release toxic styrene.

      It would be much safer when used as a worm farm container due to the lower temperatures. The high bacterial activity in a worm farm would most likely break down any styrene released, here’s an extract from a scientific publication on bacterial degradation of styrene:

      Fron the book “Microbial Degradation of Xenobiotics, Environmental Science and Engineering” by editor Shree Nath Singh, Springer Science & Business Media, 2011 ISBN 3642237894, 9783642237898 is the chapter Microbial Styrene Degradation: From Basics to Biotechnology by Dirk Tischler, Stefan R. Kaschabek, from which is the following summary:


      Styrene, the simplest representative of alkenylbenzenes, is one of the most important monomers produced by the chemical industry today. The compound shows a distinct toxicological behavior and is classified as a possible carcinogen due to its metabolism in human via a highly mutagenic epoxide. Considerable amounts of styrene are released by emissions and effluents during production and usage in polymer manufacture and by deposition of industrial wastes. A high chemical reactivity as well as its natural occurrence are reasons for the ubiquitous presence of styrene-catabolic activities among microorganisms. Rapid breakdown of styrene occurs in soils and aquifers under aerobic as well as under anaerobic conditions. As a consequence, styrene can be classified as readily biodegradable. Furthermore, a high volatility and susceptibility to photooxidation prevent bioaccumulation of styrene.”


  3. I have been growing my worms in plastic worm containers now it is getting cooler they have been escaping so I have built foam boxes to keep them in they will be warm in the winter and cool in the summer


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