The potato plants are thriving in this vermicomposting bed
One month ago I wrote about some experimental grow boxes I had set up to see how well potatoes and bush beans would thrive in an active worm composting system (see ‘Worm Bed Potato Gardens‘). I was initially a little pessimistic about my chances of success, since unlike the vermicomposting trenches – which are essentially separated from the actual main plant growth zone – the potatoes would actually be growing right in the composting mass. My worry was that the volume of material in the bin would not only continue to decrease, but would also be unstable in general – due to all the activity of the worms down below.
In all honesty, the bush beans have not really thrived at all. My suspicion is that this has something to with the fact that, as legumes, these plants rely on a symbiotic relationship with Rhyzobium sp – the specialized group of bacteria that help them fix nitrogen. Given the fact that there is no soil in these boxes, and that it is a microbially-competitive environment (likely favoring those species adapted for life in a compost heap), it’s not really all that much of a surprise. Interestingly enough, aside from showing fairly poor growth, the bean plants have been quite yellow in color – often an indication that a plant is deficient in nitrogen. I did attempt to inoculate the plants with some soil (and plants) from patch of Black Medic (Medicago lupulina) – another legume – growing in my lawn, and it actually seemed to work (it worked very well in some other bean grow boxes I will write about in another post). I think it was simply a matter of being too little too late however.
As for the potatoes…
One look at the picture above should tell you just how well they are doing! I am starting to think this method may actually be a REALLY great way to grow potatoes! Of course, the real test will be to see how the potatoes look once it is harvesting time, but I’m certainly feeling optimistic! One or two people mentioned (in comments after the last potato post) the fact that it actually helps to continue mounding up material around the stem of the potato plant as it is growing, since this can lead to the formation of more tubers. As such, all the sinking and layering of materials taking place in these boxes may actually be exactly what these plants need to produce more spuds.
Essentially, what I’ve been doing is adding aged horse manure then covering it with straw. Once the level sinks noticeably, I add more manure (on top of the straw), along with a new layer of straw over top.
Aside from seeing how the potatoes would grow, I also obviously wanted to see how well the system would function as a worm bin. Initially, I was a little worried that the worm habitat would overheat by sitting out in the sun all day long. I’m sure our relatively cool summer has helped, but in all honesty I think my fears were unfounded. The worms seem to be doing extremely well, especially now that they have a nice canopy of foliage to shade the bin.
All in all, I am super excited about the results of this experiment since it has far exceeded my expectations…so far!
Stay tuned. More updates on the way (I will write more about my other vermi-gardens as well)
It has been a very long time (almost two months) since my last dryer lint worm bin update, so I figured I should check on the bin the other day to see how things are shaping up. It’s funny – a lot of people seem to stress out about making sure they don’t starve their worms, but the fact of the matter is that it is a LOT harder than you might think. I have tested this (without really thinking about it too much – haha) on many occasions – this lint bin being a prime example. Apart from the food that was added when the bin was set up initially (at the beginning of April), and the odd batch of coffee grounds since then (I think I’ve added about three coffee filters with grounds), this bin has received nothing in the way of inputs – yet the worm population seems to be thriving.
When I last wrote an update, it looked as though most of the lint was still intact. Well, it definitely looks like a lot more of it has decomposed now! There didn’t seem to be much in the upper few inches of the bin that looked like lint. Further down in the bin was a different story however – near the bottom on the bin I found layers of wet, compacted lint that looked as though it hadn’t undergone much decomposition at all.
Much of the original lint seems to have been converted to rich vermicompost
This is not surprising at all – I have seen this many times in plastic tub worm bins, and it is almost certainly due to the lack of oxygenation in the lower reaches of the bin (I don’t have holes down there).
All in all, I must say that I’m pretty impressed with lint as a worm bin bedding material. I think it would be especially valuable in a bin that also contains other bedding such as shredded cardboard, since it provides a bit more of a wet ‘habitat’ zone, while the cardboard etc would be valuable for soaking up moisture and more quickly balancing the C:N ratio in the bin. I think the next step will be to test this on a larger scale – perhaps I will try adding a bunch of lint to my big outdoor bin, or my trenches.
Anyway – I will certainly keep every one posted!
50 Cocoon Challenge – the Next Generation!
Just thought I’d provide a quick (but important) update for everyone today. I had a look in the original 50 Cocoon Challenge bin yesterday to see how things were coming along, and not only did I notice that almost all the worms in the bin are now mature, but I actually found some new cocoons!
I tracked down at least a few just to make sure that I wasn’t finding old cocoons that didn’t hatch. Aside from the fact that there were multiple cocoons (that hadn’t been noticed the last time I looked in the bin), I am quite confident these are new ones simply based on the appearance. Recently laid cocoons definitely look different than those that have been sitting for awhile. Generally they are firmer and lighter in color, and the ‘neck’ zones (where clitellar mucus ring becomes constricted and closes) tend to be more pronounced.
Just as an aside – I also quickly checked the manure bin yesterday and was not able to find any newly hatched worms. I’ll be sure to let everyone know when that happens.
I should also mention that I’m thinking about starting up yet another 50 cocoon challenge – this time using only moistened cardboard. This was a suggestion from one of our readers, and I think it will be a fun one to test out as well! These cocoon challenges are getting addictive!
I received an intriguing email recently from Janet Walker, who is a member of the Earthworm Interest Group of Southern Africa (a group I am now actually an ‘international member’ of), and a vermicomposting professional in South Africa. I asked if I could share what she wrote, and she happily obliged.
One of my worm clients recently came to see me at our Organic Market to tell me that she had gone on holiday having fed her worms well to make sure they did not starve. She was away for ten days, and on her return she did not find any worms in her system. On asking what she had fed to her worms, we have now discovered that leaving a WHOLE pineapple, cut in half, is a worm digester. I did not know that pineapple contains one of nature’s best digestive enzymes, as does papaya and the poor worms got completely digested.
This is really interesting, and not something I was familiar with. I know that pineapple is extremely acidic and have always basically considered it in the same category as citrus as far as adding it to worm bins goes (ie only in moderation). I have never heard of it completely wiping out a population of worms however, nor was I aware of the fact that it contains digestive enzymes. I have heard that Papaya can be good to eat with meats for this reason, but again haven’t really thought too much about the potential dangers of adding it to your worm bin – it definitely does make sense though!
Anyway, I will be curious to see if anyone else has experience with these two potentially-dangerous worm foods.
Thanks again to Janet for sharing this info with us!
An interesting question from Jake:
I am confussed. I see people s[ell] worm tea and stuff and
that is the reason i bought a [w]orm factory thing. But the other day i
drained a little bit of the worm tea mixed it with a little bit of
water and sprayed it on my plants. My pomagrante tree it seemed over
night got these yellow color to some of the leafs?
Is there a wrong way to use the worm tea? i even saw one website that
said it was toxic and not to use the worm tea liquid on plants. What
is the deal?
This is an excellent question – thanks for writing in.
I’ve written about this topic numerous times, but it’s definitely one that deserves to be revisited from time to time.
Unfortunately there seems to be misleading information provided by some worm bin manufacturers (and website owners). The terms ‘worm tea’, ‘worm compost tea’, ‘castings tea’, or ‘vermicompost tea’ should actually refer to the liquid fertilizer created by steeping (soaking) quality castings/compost in water (often aerated) for a period of time. The problem is that many people refer to the liquid that drains out from a worm bin as ‘worm tea’, when the proper term for this is actually ‘leachate’.
Obviously, we’re only talking about words here so it probably seems like I’m splitting hairs, but keeping the distinction between these terms is actually quite important. While leachate can certainly have value as a liquid fertilizer (especially when drained from a mature worm bin), it should be treated with a lot more caution than good quality worm tea. As water passes down through a worm bin it can pick up all sorts of unstable metabolites (various products/intermediates of the decomposition process) – if for example, you can some fairly anaerobic zones in your worm bin, you can end up with various phytotoxic (plant harming) compounds in your leachate.
Finished composts are much better to use for worm tea creation because they are much more uniform in composition, and the vast majority (if not all) the potentially harmful compounds have been converted into something more stabilized. The microbial community present in these materials tends to be more beneficial as well.
Again, I’m not trying to say that leachate is “poison” and should never be used – I just recommend taking some extra steps, or at least using it with caution. I would probably dilute it and aerate with an aquarium air stone before using it myself. You can probably get away with using it outdoors and with hardy plants, but I certainly wouldn’t recommend putting it straight on houseplants or using with plants that tend to be a little temperamental.
Anyway – I hope this helps to clarify things for you a little, Jake.