Gardening With Red Worms – Additional Thoughts

Extensive Roots in Red Worm Habitat
Extensive network of roots growing through Red Worm habitat zone

As I alluded to in posts (and comments) from earlier this week, I wanted to share some findings relating to my trench and vermi-mulch gardening systems from this season. There is no doubt that I have been hugely impressed with both of these methods – clearly (at least to me anyway), they both offer real value in terms of helping crop plants to thrive without the use of any (off-the-shelf) fertilizers.

All along I’ve also predicted that they would be a great way to raise composting worms concurrently (especially in the case of the vermicomposting trench). I’m certainly not here to tell you that that is now 100% not the case, but nevertheless there are still some important considerations to…uhh…consider! (haha)

While the main root zones of plants growing adjacent to these systems are actually growing in ‘regular’ soil, what I’ve discovered is that the plants still send out a VERY complex network of superficial roots into these worm composting zones. I would imagine that in the case of the trench systems, this root network is even more expansive, since the compost-rich zone extends quite a ways below ground level.

Not too surprisingly, what this means is that the plants are constantly sucking water and nutrients out of these areas. Last summer this certainly didn’t make any difference because I was constantly adding heaps and heaps of water-rich food waste (from the restaurant I had teamed up with), but this year – now that I am using mainly manure, and have not feeding nearly as often – I have really noticed the sort of impact the plants can have – especially during extended periods of dry weather!

Composting worms (even more so than some other earthworms) rely heavily on relatively high moisture contents to maintain a given ‘normal’ size. They are basically little bags of water, thus when moisture is much more scarce, they can shrink greatly in size. What I’ve been finding during my recent surveys of various trench and vermi-mulch habitat zones is that many of them seem to now be loaded with zillions of teeny tiny worms! The areas when there are still lots of normal looking worms (such as in my big wooden worm bin), are also those areas that have received more wet food waste (and/or water) – or at least areas that have been able to retain moisture more successfully.

The material in some of my trenches has now sunken well down below ground level – certainly makes me realize that setting up some sort of a ‘batch’ (adding everything all at once then letting it sit) trench at the beginning of the season might not work as well as I had predicted (this isn’t what I did myself – but I’ve always thought it was an approach that might work well for others who didn’t feel like continuing to ‘feed’ their trench systems).

The vermi-mulch gardens seem to have been hit the hardest, especially now that we seem to be going through some sort of end-of-season drought period. I recently started cleaning up my bean and chard garden and noticed that the mulch zone was very dry, with seemingly few worms in it. Upon closer inspection I realized there were actually lots of worms, but they were very small for the most part, and seemed to be congregating in zones with slightly higher moisture content. I ended up raking up most of the mulch material in that bed and adding it my wooden worm bed and another garden bed where I’ve been consolidating groups of worms. I think it’s going to be fun to see what happens when these worms re-hydrate!

I am certainly not trying to suggest that composting worms can’t be raised in beds associated with gardens, but what I AM now much more aware of is the fact that these beds may need a fair amount of extra food/moisture if you want to provide the worms with anything close to ‘ideal’ living conditions. Obviously maintaining thick layers of straw etc over top can certainly help to reduce evaporation, but it doesn’t provide much protection against the water-sucking potential of all those roots and rootlets!

I suspect that if you maintain a decent sized windrow of good food/habitat material over top of your trenches, making sure to add new stuff at least once a week, you’d be fine. The vermi-mulch approach is obviously a lot more susceptible to drying out (since all above ground), but I’m sure that if you are diligent enough with topping the beds up with new material (and adding water), the worms would thrive there as well.

For all of you who may have experienced something similar, and are distressed that your worms have ‘disappeared’ – I highly recommend that you start by adding a LOT of wet food/habitat material, assuming you are still growing plants. If it is the end of your growing season however, you may want to try and consolidate your worm population as much as possible – perhaps setting up a new bed dedicated to concentrating (and fattening) as many worms as you can round up, so that they can then be moved to new indoor systems (or even ‘put to bed’ back in your trenches for the winter – something I will certainly be writing more about this fall).

I will be very interested to see what others have to say about this. Any similar findings? Contrary findings? It would be fun to get a discussion going.

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  1. Extrapolating from this, just how often should we be watering a bed?
    Perhaps some sort of combination of weather, cold, cool, warm, hot and
    indoor plastic, outdoor ‘bin’, mixed veg/worm bin, mixed veg/worm bed.

    I tend to only water my worms when I’ve noticed it has been dry for a long time,
    i.e. I’m even lazier than you! Perhaps a better solution would be to tell us the signs
    that we should be looking out for when the bed is too dry?
    I guess in my case (slatted sides) it’s when the sides of the bed have totally
    dried out, even if the centre is moist.

    Any advice please

    • Candin
    • September 21, 2009

    I too wonder how often an outdoor bed should be watered. I had read that if you are attempting to force breed, you allow the top few inches dry out and the worms will mass produce. I have open ground pits with good drainage so overwatering is not a real problem. Perhaps tomorrow I may go and add some more water to one of my beds. Plus using rubber gloves its difficult to check the moisture level of the beds.


  2. I’ve noticed that when I’m ‘curing’ castings and letting them dry a bit, the worms hatched out of the cocoons in the castings are much smaller than the ones in the worm bins themselves. I’ve seen mature worms (with good fat clitellum relative to the rest of their bodies) under 2cm long.

    • Bentley
    • September 25, 2009

    DAVE – it’s tough to provide any sort of concrete estimate for the amount of water (and how often) to add, since there are so many variables to deal with. I am definitely like you in that I usually only do something about it when I notice that things have really started to dry out.
    The beauty of outdoor systems that are open to the soil is that it’s tough to add too much water, so if you want to keep your worms really happy and ensure that conditions never get too dry, simply water every day or two.
    Materials with an ‘ideal’ moisture content for compost worms should look wet. As long as the worms were getting enough oxygen, they would more than likely be happy to basically live in materials with close to 100% moisture content (tough to achieve though since water can only hold so much oxygen).

    CANDIN – Forcing worms to breed by drying out is an interesting idea and does make sense since the worms will want to ensure the success of future generations. Cocoons are certainly a lot more resistance to drying out than the worms themselves. This is why people should never give up on a bed that’s dried out – there will still be LOTS of future worm potential in the material. As for checking moisture levels, while you certainly can do so with your hands, I generally look for visual clues (literally as basic as ‘does it look wet or not?’)

    CATHERINE – Thanks for sharing your observations. This is very similar to what I have seen myself. When I first started harvesting vermicompost from my backyard worm bin last year, I found a HUGE number of teeny tiny worms in the material. It was likely a combination of factors – primarily low nutritional content, and low moisture content – that caused this. Red Worms are able to adapt to pretty harsh conditions, and often this involves conserving resources by shrinking greatly in size.

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