Thursday, 23 July 2009

Wicking Worm Bed Questions?

I've recently received some questions via emails and in person about the Wicking Worm Beds beds.

Will the beds become waterlogged in heavy rain?

Remember this diagram from this link on The Basics of Wicking Beds (click it to see it better)
In the left hand, bottom corner is a tag called "Gap for Overflow".

If the wicking beds are built with an adequate drain hole (Gap for Overflow) above the bottom "pool" area they should not fill above that level. The excess will "leak" away.
As the growing area is raised there should be no chance of flooding, it will drain naturally.

Make sure the "soil" you fill the bed with has lots of compost in it. The plants will use the water as in "normal" beds, these raised beds will have better drainage that "normal" ground level beds.

In my "in ground" beds this drain point is at ground level (but doesn't have to be) and I can see the water escaping from that point so I know when the beds are full. This is also where any excess rain will escape.
If this point is lower in the ground the theory is that excess water will drain into the surrounding soil. That is providing the surrounding ground is not already saturated.

The only time I have noticed a problem was in some of the older Wicking Boxes.
The holes in the side had become blocked and were not draining. During a reasonable downpour the worms were escaping everywhere! I fixed this by putting a short piece of poly hose in the hole to drain them.

These older boxes were made with vegetative matter in the base, this has now collapsed as it has broken down and this seems to have caused the blockage.

The new boxes I've made this year have a 15cm piece of 13mm poly hose inserted through the hole in the side. They seem to be draining successfully now.
I'm also using a mixture of small gravel and sand in the bottoms of the boxes and 'stacking' some gravel around the outlet holes for drainage and to help prevent them clogging.

While it is raining regularly, even a little, you should find less need to water (filling the bottom pool area should not take long at all). One of the best things about these beds is that they make full use of any rain that falls on them.
I have only this week needed watered the beds since May.

Another question was about the size of the beds.
Basically you want them wide enough to be comfortable for reaching into the middle. You can not walk on these beds. Apart from squashing the worms you will compact the soil and reverse all of the good work they do aerating the soil.

The length of the beds would depend on how level your site is. The bases of these beds must be perfectly level for the wicking process to be uniform throughout the bed.
If the water pools at one end that is lower, that end will be wet but the other areas will dry out too much. It would be better to build smaller beds and 'terrace' them down the slope.

I did not remove the curtain covers from the beds this winter. This seems to have given the plants shelter from the cold as growth in these covered beds has been more successful than in others I have left uncovered.

It really is important to start growing winter vegetables during summer though. Most of the seeds for these crops were sown in early January. They need to be well grown before May when our cold weather sets in and growth slows down.


  1. Scarecrow, you are such an expert gardener! Your vege garden just looks great! :)

  2. Hi Scarecrow,

    I don't have any wicking beds but I do have wicking boxes (21 at last count!) and like you, I was finding drainage-hole blockages in some cases. I decided that my original drainage holes were a bit small and drilled them out slightly and that seems to have solved the problem. However, I regularly poke a large nail into all the holes to keep them clear. It's only really been a problem in the winter with excess rain. In the summer it's a job to keep up with adding the water!

    Bev (aka foodnstuff)

  3. Awww thank you SM
    You can leave comments like that one anytime :)

    Thanks for your feedback Bev!
    Wow you have been busy with those wicking boxes.
    I agree that they didn't have any problems during summer, maybe we are just not used to rain anymore! ;)

  4. Hi Scarecrow,

    I'm finally constructing my first wicking bed. I first heard about wicking beds on this site. The past few weeks i think i have looked at every wicking bed site google has to offer. A question for you though, as you have been operating your wicking systems for a while now i presume. I am concerned with what to put between the water resevoir and the growing medium. Do you think hessian bags would be good? It's just that i have access to some. But thought they may break down too quick. I also have a roll of frost cloth (white stuff, looks like interfacing)What would you use? We have chosen medium coarse sand for the water base.

    Apreciate your thoughts..

  5. Hi Robyn
    It's great to hear that you are trying this system!

    I have not used any barrier between the layers (or anywhere) of the in-ground beds. The ones I have needed to rebuild (for whatever reason) still have had sand evident in the base layer. I also found no sand/soil within the watering pipe so barrier cloths seem unnecessary.

    I don't think it would matter too much if this base layer did have some of the 'soil' mixed in with it as it is only a water storage area. Plant roots are unlikely to survive the repeated wetting that occurs at this level (only). The same would apply to the worms.

    I do think that hessian would break down quite fast not only from the water but I should think the worms would eat it! :)

    The best way to get to know this system is to try it. What works for me in our very dry climate here may not work as well in wetter more humid areas.

    When you do experiment please share you knowledge either here or on your own blog as others may find the information useful.

    I hope this helps and please don't be afraid to experiment!

  6. Would roses grow successfully in wicking beds/boxes?

  7. Hi Anonymous
    I should think they would grow OK in a deeper in-ground bed. A box setup would probably not hold enough soil/growing medium for their root system.

    Give one a try!

    I don't grow roses as I am allergic to them and I prefer to grow food! :)

  8. Hi Scarecrow, just starting out with wicking beds. They seem awesome and really so simple. I do have a question though. I have recently been given 3 apple crates (and will be getting heaps more soon) and am going to turn them into wicking beds. Each of the three I have done slightly differently. They are all lined with plastic, but the rest is differnt:
    1) Straight garden soil with drainage slits halfway up the crate on all 4 sides. Handfull of compost worms thrown in.
    2) bottom half filled with straw and then soil on top. Handfull of compost worms thrown in.
    3) (still in construction) will put slotted pipe down, fill to the drainage slits with sand/gravel mix (left over from concreting and I am assuming salt content is minimal to none) and then top up with garden soil, making a worm bin in one corner, full of compost worms. The worms will make their merry way out through holes and I will feed them kitchen scrapes through this bin.
    Given that the crates are 700mm deep, do you think these 3 systems will work?
    I am hoping that the first two will not get water logged (I have made three other beds the same way at 750mm high and so far they seem fine). Your thoughts are more than welcome!
    Here is my blog:

  9. Hi Quachy
    I hope my email answered your questions.
    Good luck growing your food, the garden looks great!

  10. Just dropping in to say 'hi'.
    I'm researching wicking beds as I've heard they produce fabulous results, and I came across your blog.
    I'll probably be back a few more times to check out ideas before setting up our own system.

    Thanks for all you've written so far!!

  11. Hi Alecat
    There's loads of wicking bed info around now it can become confusing.
    Go with a method that feels right for you and you won't regret it.

  12. Hi scarecrow! I want to try your beds. From what I gather from your site, in a nutshell, you use foam boxes (from grocer?), drill holes in base and a larger hole in side and angle a short bit of tubing. You then fill the base with sand/gravel - do you fill to below or abo e the drainage pipe? - and top the rest up with soil/compost and then plant and mulch. Is this right?


  13. Hi Mrs Bok
    The boxes I use are Broccoli boxes (with no holes in them) we actually got ours from the local pub...they get their veg delivered in them and can't send them back!

    NO holes in the bottom/base.

    One hole about 10cm up from the base for drainage. We are making a reservoir for water in the base here, this hole is to ensure the box doesn't fill with water.

    A length of hose with holes in it (drainage pipe or other large hose with holes cut or drilled into it) this sits at the base of the box (inside it) and comes up the side to allow water to be added to the base.

    The tubing (at the side) is not at an angle it just helps to keep the hole clear of potting mixture. You can wriggle it if you think the hole is blocking up.

    I now use sand/gravel mix in this base area but others have used straw and other compostable material with success. I prefer one that doesn't break down but mine are now very heavy and can't be easily moved.

    I fill the sand/gravel mix to cover the drainage pipe. Up to where the drainage hole is.

    Top up with compost/soil/potting mix/coir (coconut fibre peat substitute) add compost worms and mulch well.
    You'll need to feed the worms occasionally or they will try to escape. I do this via a feeding tube or just tucking finely chopped veg scraps under the straw mulch.

    I hope that has cleared things up for you.

    BTW I have been experimenting with large pots (with a plastic liner), big buckets and other large containers too.

  14. Hi Scarecrow. I have studied your raised garden beds using the wicker system and am excited. We live in hot Perth and have tried unsucessfully to grow vegies... our summers are tortuous on plants but I have hope that this time it will work out as....well you live by a desert and if you can do so can I! Thank you for the inspiration SC.

  15. Hi Laneypoo
    Good luck with your wicking beds. Just remember mine are covered with shade cloth on polypipe/hose structures. It helps to keep the hot winds off the garden too!

  16. Greetings from Southern California, Scarecrow! I am very excited to put together a front-yard lettuce and herbs box on the Friday after Thanksgiving, in a few days. Question, please: Is the worm can/pipe (which I gather accepts kitchen scraps) essential for the success of these? I suppose they need to eat something... If it's a pipe, which I'm inclined to do, does one simply drop the scraps down it -- is it that simple? Also, given that the box will be visible from the street, would wood rather than metal or styrofoam be an acceptable material for the structure? Thanks! Living in LaLa Land

  17. Hi Anonymous
    Wood would be fine as long as you can make the bottom 'pool' area sealed. Make sure the wood hasn't been treated with toxins.

    As for the feeding tubes, this post will give you some hints on making that easier.
    I now use the pulp left over from our morning veg juice and the worms love that.
    Yes you put the food scraps down the tube.
    It is best to cover the food scraps with a lid or mulch layer to stop flies getting it. Yes it is that simple really. They don't need feeding everyday.
    Sometimes I just tuck soft leaves or flower debris under the mulch layer for the worms to eat too.

  18. This is fantastic -- thank you SO MUCH!

  19. Hi there SC, love your site. Being a novice and actually understanding the methods being described by you is really liberating so a big thankyou for your practical explanations.
    I live on the Eyre Peninsula and we have crazy snail and millipede problems so just wondering if you had any suggestions r.e keeping them out of garden beds. (The boss has forbidden us to have chooks).
    Many thanks

    1. Snails I can cope with as they are easy to see and on a damp night we collect many and squish them. Coffee grounds are supposed to help deter them as is a coffee spray...I am still testing this as the slugs keep climbing over coffee grounds but I am yet to actually spray the coffee solution. Rain would wash this off but it is supposed to be the caffeine in it that actually kills the slugs and snails.
      This is an interesting note about farmers using caffeine against snails.

      As for those pesky millipedes I know that they love mulch so clearing the bed at planting out time will help, as it does with earwigs, then putting the mulch back but carefully sifting through it to get them out. This will cut down on the numbers but I am investigating a couple of traps that rely on a light source to attract the millipedes here's a link with some more info. I am thinking of trying this around the strawberry patch with a cheapo garden solar light for the light source.

      Keep pushing for those chooks!!!!

    2. Thanks for the prompt reply SC. Unfortunately the boss says chooks = rats = snakes and when her minds made up......
      So when we build on our own10 acre block later this year I am going to have a go at building one of these with the help of a few mates and use a combination of wicking beds and aquaponics (both really affordable) which will hopefully allow for better pest control as there's nothing more disheartening than actually getting something to grow only to have it ruined before it gets on the dinner plate!
      Thanks again for all your advice in this blog.

    3. Wow! Good luck with the move...what you are planning with the dome sounds fantastic!! I reckon the combination of wicking beds and aquaponics inside a green house type structure will be great. The water in storage within the systems will help with heat retention. Win-win situation and fewer pests!

  20. Has anyone heard of using polystyrene balls instead of gravel or scoria in wicking beds ? I have a few old bean bags about the place and it would save money if they can be used. My only thought is that they may not be absorbant but would this matter?

    1. I did think of this but didn't have a supply of the balls just old boxes that would need to be broken up. I think they should work OK.

      The only concern with using them in the base is that some people don't like to use polystyrene at all. These people wouldn't be using these boxes either. If you are comfortable using polystyrene then try it.

      Other than that you may find that the balls squash down after a while, maybe an issue, might not.

  21. I am thinking of using an icecream container filled with sand in it placed in the bottom of a bed. Fitting a garden or polly hose from the inner container sloping down to a drain hole at the side of the bed. The rest of the bed filled with soil. If including a water filling system maybe place slotted tube with a tee piece directly down into a second sand filled icecream container.
    Possible advantages
    1. Minimal sand required meaning minimal total weight.
    2. If the drain hole is sealed properly, the height of the inner container should determine the reservoir height of the bed.
    3. The sand with a bit of mesh at the start of the drain tube should stop soil and sand getting in.
    4. The slope of the drain hose should prevent water pooling in the hose to avoid mosquitoes breeding.
    5. The slope of the drain hose should also help to drip any excess water away from the side of the bed.
    6. To be water wise, any excess water could be collected in a plastic container or bucket and reused before more water is required to be added. (Empty water storage container regularly to avoid mosquitoes breeding.)
    7. Using the filling system should prevent overfilling of the bed as the filling tube will start to overflow.
    Cheers Greg

    1. Hi Greg
      Sounds good...I would be interested to know how it turns out.


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