Worms!

[Sylvia Bernstein]

There has been some (much?) chatter on other AP forums about using redworms in your media beds to "process" your solids.  I love this idea!  Not only are the solids removed, but the plants benefit from the vermicompost.  I added about a pound of worms in my six beds a few weeks ago, and I'm hoping that they are happily going to town in there.

So here are my questions...

Do you use worms in your system?  How many to use per square ft of bed?  When do you add?  Do you feed them something (food scraps) besides the delicious fish solids?  

[Daniel E Murphy]

So far so good with the worms. I have them in all my beds as well. I made a key observation while at TCLinx garden this weekend. She had a worm in her biofilter. She pulled it up to show me the beneficial nemetodes and here little snails etc and i noticed a good ole earthworm with that little white band just enjoying itself on the filter. Those little buggers seem to live anywhere in the aquaponic system they want to as its highly oxygenated. I suppose they get in the drains and then who knows where they end up and how they continue to benefit the system. I imagine as fish food sometimes.

[Sahib Punjabi]

Video from Murray Hallam - AQ Secret Weapon...Worms...in gravel :-)


Kobus Jooste said:

I have looked at the worm debate a few times, but have not added any in my systems yet. First, I will have to try and find the correct species down here. Second, due to the lack of volcanic rock and the robbery price of hydroton, my systems are entirely gravel. Can worms really navigate the heavier media?

[Murray Hallam]

Hi, Red wrigglers is the common name used I think....for the common type that does well in AP grow beds.
Re the gravel -v- clay pebbles. I have observed over a couple of years that there is a larger population of worms in beds that have the 3/4" gravel. The only factor I can think that will account for that is there are better pathways for the worms to move about in a 3/4" gravel bed, than there may be in a clay pebble bed. I should add, there are plenty of worms at work in our clay pebble beds. Use the media that suits your personal needs best. The worms will do their thing.
We have clients that have gone to the garden shop and purchased a box of 1000 "composting worms"....distributed them around their grow beds and they all report that the worms are doing well.
The worms need something to work on, so if you have a very new system you may need to install a worm feeding station right up at the beginning. (it is a good idea anyway) The size of the worm population will be regulated by the food available to them.
The video clip shown above is a "blooper" It was some film we did when making "Secrets" Frank filmed it using his digital SLR , not his proper camera, so that is why the focus is a bit "not good" , but the clip is very useful in showing worm activity in a mature grow bed. That particular place where we dug for the worms is beside the inlet to the grow bed where the water comes in directly from the fish tank, so that is the "best seat in the house" as far as the worms are concerned. The fresh fish poop arrives right there from the fish tank. The worms love it!!!

Kobus Jooste said:

Thanks a stack Sahib. Now, next question - does anyone (I do not have Murray's DVD, in case it was in there) have the species or at least genus name of the correct worms for the job?

Sahib Punjabi said:

Video from Murray Hallam - AQ Secret Weapon...Worms...in gravel :-)


Kobus Jooste said:

I have looked at the worm debate a few times, but have not added any in my systems yet. First, I will have to try and find the correct species down here. Second, due to the lack of volcanic rock and the robbery price of hydroton, my systems are entirely gravel. Can worms really navigate the heavier media?

[TCLynx]

A++ Kobus,
I so totally agree with you and I love the way you explain it. Good stuff.

[Daniel E Murphy]

Indeed great stuff!


Kobus Jooste said:

Being new around here, I keep on stumbling on topic's older entries that I feel I can add to. I have read through most of the buzz around "nutrients", but as ecosystem energetics is a focus area of mine, felt compelled to want to add something about this.

Whether you add or do not add anything other than fish food is your choice, but note that animals do not need all the elements required by plants, and thus the most expensive fish foods may still not do the job. That said, when I see an aquaponic set-up, I see an ecosystem. In energetics, we normally describe the passage of either carbon or nitrogen as it passes through an ecosystem. You have your introductions, or sources, you have your various trophic levels of users, and ultimately you have your exports and recycling pathways. It is in those pathways that aquaponics finds its strength. You do not want to export like the dudes at UVI. It is done in gravel, in net tanks, in biological filters and even on a dense mat of roots. The processes that we want to see happen in aquaponics all consume oxygen, but give us the nutrients in its most basic form, which can then be absorbed by plants.

As those with gravel beds may know, you can run an AP system without fish for a long time, and the plants may still grow. That is because of the slow process through which solids continue to be broken down (mineralized) by microbes. At a far greater pace, bacteria can deal with dissolved nitrogen and give us nitrates in return. If you wanted to, you could take it a step further and denitrify, but then what would that help. So you have "fast" nutrients coming from bacterial actions, and "slow" nutrients coming from all the microbes dealing with the solids. The fast stuff is normally macro-nutrients, while the "slow" stuff is often a lot of the trace elements and micro-nutrients we all feel compelled to add. What the worms do, is speed up the mineralization of the solids - putting it through its gut and releasing a form of nutrients that is available to plant. Without the worms, the process will take place, but slowly - you also have the chance of "loading" faster than what you can break down, leading to clogged beds.

Worms therefore mobilize nutrients from a "sink" situation, where it is gunk in your gravel bed, through a fast nutrient recycling pathway back to a soluble state available to plants. Great stuff for AP. As a side, they do consume oxygen and part of the solids they chow becomes biomass, thus it is not all free for you, but it still helps a great deal.

[Joseph Orlando]

Wow! Thanks Kobus, I look forward to the results on your research with Lemna gibba, duckweed. In answer to your earlier question, the scientific name for Red Wigglers is "Eisenia fetida". However, I am going to use either my African Nightcrawlers "Eudrilus Eugeniae" or European Nightcrawlers "Eisenia hortensis" in my growbeds, and as a feed for the Tilapia. According to Dr. Lori Marsh, a professor at Virginia Tech., who recently sent me her papers regarding her own research on red wigglers, mentioned in a recent phone conversation that the "fetida" part of their scientific name refers to the distaste fish have for them. She said the Tilapia may eat them once but would probably avoid them a second time. Ha! Go figure...picky fish! Or, known in scientific circles as, "fishipicius"! heh... At any rate, she also mentioned that as I gear up my worm beds I would probably find that what I could get on the market for them as bait worms will probably convince me to sell them as bait and use the profits to buy fish pellets! Thars gold in them thar bins!



Kobus Jooste said:

I'm not sure if anyone else have replied on this. Duckweed (which species though?) and some source of insect protein such as worms or black soldier fly larvae has been proposed as a sufficient nutrient base for tilapia, but I have not tried it. I am working towrds creating a duckweed (Lemna gibba) aquaponic system for research purposes. The basis for my research is that Lemna, and most other duckweeds, can concentrate nutrients in their cells as far greater concentrations than in the water. Manipulate their water, and you may be able to grow a complete diet for tilapia. Mine (Mozambique tilapia) absolutely love the stuff. I supplement with it at the moment, but as the research matures, I'll do more detailed trials. Just for interest - most tilapia foods contain mid 30% protein of fish meal source. Lemna can be grown to have a more digestible (but very close to animal) plant protein concentration of over 40%, lipids up to about 9% and carbs of up to 43%. It can also absorb every trace element, metal and nutrient needed in aquaponics. Thus, grow it correctly, and my hypothesis is that it can become a single, or one of two dietary items needed in an AP system.

Joseph Orlando said:

[TCLynx]

The composting worms I got were a combination of eisenia foetida and lumbricus rubellus. We have occasionally fed worms to the fish and I've never noticed any of them being rejected. However, it can be a challenge to grow enough worms to really make a big dent in the feed requirements. Same as the situation with growing duckweed, I've never quite developed a method to grow enough easily.

Worms are generally quite easy when you are just running a small worm bin or worm farm you get to harvest castings and feed them your kitchen scraps and perhaps pull out a few worms to feed to the chickens or fish. But, when you are talking about wanting to harvest pounds of worms per day or week, you suddenly need a far larger feed stock for the worms than just some kitchen scraps or fish poo. Feeding enough to have a large volume of worms ready to harvest regularly requires a waste stream enough to feed them up as well as a ready supply of bedding material to keep things from getting nasty.

[Joseph Orlando]

TCLynx, You are absolutely right. As I grow my worm beds it's interesting to see just how much it takes in veggies. I have two supermarkets here in town that are happy to give me anything they have pulled from the counters for the day. The less they put in their dumpsters the less they have to pay to have them dumped. However, you may run into some resistance if you go to your supermarkets. It seems that insurance companies will not allow them to distribute any veggies or fruits they deem to be past selling point. I guess people have asked for these and then complained or even sued if they got sick. The supermarkets here have stainless steel shoots going from the building directly into the dumpsters to prevent anyone from even getting to them from the outside. However, since I approached them about the green aspects of feeding the worms they consented.

In building this worm farming business I have graduated to larger and larger bins having started out with plastic storage tubs. I am now talking to the county about their used beyond use dumpsters to adapt to even larger bins. You can build a large population of worms rather quickly. Prolific little buggers, but you have to be patient and let those populations grow out first. It is quite possible to create a system that is producing however many pounds of worms you need a day.

As I said in my last post, it was pointed out to me that the worms are probably much more valuable in the bait market than as fish feed. The castings they produce are even more valuable.



TCLynx said:

The composting worms I got were a combination of eisenia foetida and lumbricus rubellus. We have occasionally fed worms to the fish and I've never noticed any of them being rejected. However, it can be a challenge to grow enough worms to really make a big dent in the feed requirements. Same as the situation with growing duckweed, I've never quite developed a method to grow enough easily.

Worms are generally quite easy when you are just running a small worm bin or worm farm you get to harvest castings and feed them your kitchen scraps and perhaps pull out a few worms to feed to the chickens or fish. But, when you are talking about wanting to harvest pounds of worms per day or week, you suddenly need a far larger feed stock for the worms than just some kitchen scraps or fish poo. Feeding enough to have a large volume of worms ready to harvest regularly requires a waste stream enough to feed them up as well as a ready supply of bedding material to keep things from getting nasty.

[Natalie Desrosiers]

So we have established that worms can be fed to fish and worms can be put IN the plant beds to break down solids. I have also heard of having a seperate compost bin and then adding the worm castings to the plant bed. Does anybody know more about this? Any thoughts on amounts? Doesn't it make the water dirty? Just like adding dirt to the water?

[Joseph Orlando]

Natalie, Actually, in my opinion it would be better to have separate wormbins. With enough space and solids in the growbeds the worms are likely to prosper and propagate, however, if you are looking for enough worms to use as feed worm bins are the only way to go. The worms in the growbeds will eventually produce enough castings to make a significant contribution to nutrients, but if you have spearate wormbins you can start adding castings right away. I think they might cloud the water a bit in the beginning, but eventually as you balance the system to the additional castings, ie. more dense plantings. the plants will absorb enough of them to keep the water clean.

Remember, the worms will also make cocoons and hatch new worms. They will continue to reproduce until they reach some kind of critical mass which is determined by the amount of space, food and whatever the worms consider comfortable. They will not over populate their area. The only over populations occur when too many worms are introduced to too small a space. In which case the surplus population will leave, if they can, or die off until their sense of population is reached.




Natalie Desrosiers said:

So we have established that worms can be fed to fish and worms can be put IN the plant beds to break down solids. I have also heard of having a seperate compost bin and then adding the worm castings to the plant bed. Does anybody know more about this? Any thoughts on amounts? Doesn't it make the water dirty? Just like adding dirt to the water?

[TCLynx]

When starting up new beds, I always add a hand full of composting worms and a hand full of worm castings. The worms are to populate the bed and take care of the solids (I don't usually worry about adding them right away because my gravel usually gets washed from a pile right out side and there are usually some leaves and debris that make it into the bed to break down right away and I generally add plants right away too so figure there will be food quick enough for my worms.) And the worm castings are added (usually just a hand full right under the water inlet to the bed) to provide a sort of worm tea to help boost the bacteria available to colonize the bio filter right away. Since I have worm bins, it seemed like the easiest kick start method.

I don't know that I would add worm castings to the beds regularly, seems the worms in the beds will be doing that as they expand their population but I suppose if you are feeding your worm bins a good variation of foods to make sure they get all the trace elements and extra potassium, well maybe castings or worm tea could substitute for the seaweed extract many use in the first year of their systems. Growing Power is a firm believer in worm castings.

[Brent Zionic]

My home aquarium system (10g tank) is pretty small, with a 1:1 ratio for the grow bed that is 12" deep.

I added a worm cage just in case I wanted to add them later, but I've wondered if my system is too small to warrant them?

Any thoughts on # of worms to add in ratio to grow bed depth and volume? I'm slightly worried they'd get sucked through my bell siphon and tossed into the aquarium, where they're probably too big for the white cloud minnows I'm using to cycle my system, currently.