Worms,

[bigdaddy]

I'm not sure if this is the right section to put this but here goes,

Hi Crusty,

I noticed on Gary's 3 mega bin thread you mentioned you were speaking to a commercial worm grower and the theory that some people spruke about using worms in a media filled grow bed is flawed.

I'm interested in why you say this,and what this commercial worm grower says about it?

I certainly have not made mind up that it works,but I have a relatively open mind if people can explain to me the reasons why.

As you may be aware I am a member of PAP,BYAP,AND APHQ forums,so I like to think I have a relatively open mind on some subjects.

I have a barra system with 1000 litre media filled grow bed,and people suggested to put worms in my grow bed,so I was happy to give it a go.

I have grown worms for a few years and I love them,so I had 2000 spare and added them to my grow bed,about three months ago,and have not seen them since,not in the grow bed nor in the fish tank.

It was suggested I put a feeding station in for the worms but I don't understand why? there is plenty of food in the grow bed for them as it is.

When I pull up some old plants I do not see worms in the root mass or the grow bed from where the plant came from.

So yes,I would be interested what you have to say about the theory of using worms in your grow beds.

Cheers.

[Crusty]

Worms are not my specialty but I do know a few people that are specialists. While they acknowledge the benefit to plants, nutrient requirements are not met by the fish alone. In a soil based culture as apposed to a clay media based culture, the worms stand to benefit due to the higher carbon content. We know the soil benefits but they can not enrich an inert media like expanded clay. Which means they can only enrich the water that goes back to the fish.

If you can keep them in your bed I think they most certainly have benefit to the plants, though to use them or even suggest they can be used as a solids filter is folly. My comment was directed at those that propose worms provide adequate solids processing within the same system through mineralization.

It was suggested I put a feeding station in for the worms but I don't understand why? there is plenty of food in the grow bed for them as it is.

I think the reason for the feeding station is, the worms can not process the liquid waste all that well, if at all and will soon vacate the grow bed (have a dig under the grow bed in the ground see what is there) without additional food source, especially a carbon source. I believe the "feeding station" is the brain burp of those that think worms are a solids filter, but is now suggesting feeding them more in a balanced system. Why anyone would put waste scraps in a "feeding station" in their beds to attract unwanted bugs to their growing plants is an interesting concept. The constant contradictions are mind boggling... popcorn anyone?

We have used worm tea (also used the black soldier fly liqueur) in floating rafts (pouring it in by the liters) and as a foliage spray with no obvious benefit to the plant growth outside what good stocking of fish and feed rates were already providing.

So if you can get great plant growth in a floating raft system that has absolutely no worms and even better growth than adding worm or BSF tea to that system, I see no logic in claims worms provide more benefit, especially in an inert clay media based system. In my opinion it is better to have good fish densities and feed rates which is the point of aquaponics rather than muck about with all these other diversions.

I would have to do more reading on worms, but some points that I can make out are:

• They require some form of bedding and poo is the preferred choice though not in liquid form such as produced by the fish and definitely not fresh poo. The clay media in the beds is not ideal.
• Temperature between 15C and 30C, which would not be much of a problem in grow beds, though winter would be somewhat slow but so in the metabolism of the fish.
• They don't like urine at all, which makes me think they are not fond of ammonia, which is ever present in aquaculture, especially in non bio filtered water to grow beds. They don't like salt or acid media.
• The carbon to nitrogen ratio (C:N) is prefered at 20-40:1, which is interesting as fish systems generally run from 5-10:1 which appears to be a much lower then an ideal carbon source for the worms.
• They can eat half their body weight per day of solid waste. Important to know the difference between solid and liquid wastes. If the waste from your fish was "dewatered" it would prove suitable to the worms but constantly suspended in water, I doubt would be much use and they don't filter the water to get nutrients.
• They do not like disturbances to their bedding at all which the flooding and draining would pose some problem. I am not sure about the excessive moisture or how this effects them.
• You could be lead to believe you would only need to seed a grow bed with 500grams of worms (2000 worms) to take care of the 250grams of waste from the fish as it sounds reasonable. On the other hand, the worms also produce solid waste of their own (castings). The only info I can find on the casting production is 2-3 per week. However, it will have a detrimental effect on water quality without a doubt.
• Worms also produce a liquid waste, for which I have the chemical break down here. It looks to be really great for the plants and I see no risk to the fish, so there is a direct benefit. The difficulty with this reading is the worm tea has been bio activated prior to the testing. This means, the direct excretion of the worms would me much different to this sample. My readings of commercial worm tea shows really high levels of ammonia, which from memory is the limiting factor in worm colonies. This sample contained E.coli as well but I do not know what the farm was feeding...
• They can be of definite benefit to your plants but to rely on them as your solids processing within the system will not work to the level you will need with reasonable stocking densities of fish.

Perhaps, bag filter and dewater the solids, feed that to the worms outside the loop and bring back the tea..water and bio activate the castings and bring back the juice from that or use it as part of your planting pot compost. Personally, I would concentrate on just growing the worms in the usual way and use the nutrient created from there. At least you then have somewhere to process your veggie waste from the kitchen. Grow beds are best not used as a dumping ground for rubbish, unless they are not connected to fish.

By all means, as I said, if you can keep them in your bed use worms as they do no harm but worms are not a solids filter.

[Rew]

I have seen obvious benefits to plants in media based growbeds when adding worm casting tea. Very quick results. More in the fruiting type vegies than the greens.

I have worms in my grow beds, but would never think of adding rotting food to feed them there. Worms help many nutrients to become water soluble. That is why the tea works so well. It can't hurt to have them in your beds and they don't try to leave. They find plenty to eat, even with filters in place. This is only based on 6 months experience, so take it as you will.

[GaryD]

Hi,

Here's my two cents worth on worms in aquaponics:

• Worms will eventually find their way into a grow bed......whether we introduce them or not. Whether they stay, or not, is determined by a variety of factors, not the least of which is that the environment is to their liking.
  
• Rather than eat large amounts of organic waste (as most people believe), worms eat mostly bacteria and similarly microscopic organisms. While solid organic waste may pass through their systems, it's the tiny organisms that largely comprise their diet.
  
• Worms will reduce the overall volume of solids in a grow bed. For every kg of food that is feed to fish, we end up with 250 grams of solids. I've read that worms will reduce the overall volume of solids by 60% so, for the purposes of this discussion, we'll end up with 100 grams of solid waste left in the beds. From this, we might assume that having worms in the bed is useful but hardly the complete answer to solids management in an aquaponics system.
  
• Biological filters (including aquaponics grow beds) are intended to process dissolved solids. The presence of sedimentary or suspended solids inhibits their function so they should not be allowed to enter the bio-filter/grow bed. Processing solids in the grow bed is the aquaponic equivalent of closing the gate after the horse has bolted.
  
• The more sedimentary and suspended solid waste that we can remove from an aquaponics system, the better.......so having a feeding station in an aquaponics system grow bed is a very bad idea. To convert kitchen or garden wastes to a form that will eventually be useful to plants (by way of the aquatic nitrogen cycle) in an aquaponics systems will require huge numbers of heterotrophic bacteria. Heterotrophs breed much more quickly than autotrophs (nitrifying bacteria) and will, in the right circumstances, overwhelm them - the exact opposite of what we're looking to achieve in an aquaponics system.
  
• If you want to feed supplementary organic waste to worms in a grow bed, consider Vermiponics - and take the fish out of the system. The fish will be much better off.
  
• Worms will mineralise solids.....which is a useful thing. The worm tea that is a product of this mineralisation makes for a valuable foliar spray for plants. This function, however, should be performed outside of the aquaponics system.

To summarise......left to their own devices, worms will perform a useful function in harvesting dead bacteria in grow beds, however, deliberately allowing solids into a grow bed with the idea that worms will adequately (for water quality purposes) deal with them is utter nonsense.

Gary

[bigdaddy]

Thanks for your replies folks,

I will have to think about what has been said and let it digest for a while.

The figure of processing solids of up to 60 percent was also quoted to me.The reason why I had concerns was I did not know (and still don't) where my worms went and why,so I am not keen on adding any more to my grow bed until I am certain they will stay.

The reason why people suggested a feeding station be attached or added to my grow beds,was the people were thinking the worms were searching for food,thats why they disappeared,and if you provided food for them they will stay in the bed.I still question that theory and am not at all convinced about that.I am more inclined to go along with what Crusty was suggesting ,that the environment was not comfortable for them so they packed their bags and left.

The good things about worms is you do not add rotting food to them to process and if you do you will find they will give it a wide berth,but you do add a layer of fresh scraps for them to process and if you keep it balanced,not to much nor too little for them they process the scraps well.

I will still stick to keeping my compost worms in my worm farms until I am convinced I can keep them in my grow bed.Once again having said all that,I am still open to advice on how to keep them in.

Cheers.

[Ravnis]

I run my worms (eisenia Hortensis) in a trickle filter that is just after a tube within a tube solids filter. The solids filter catches some solids and some makes it out.

I notice they tend to congregate at the top of the trickle filter. My current guess is because the water has more oxygen at the top than toward the bottom as surface tension is broken when it hits the filter media. They have never tried to leave it and have gone from a handful to a small trashcan full in less than a year.

I also had put a air stone at the bottom of the trickle filter to attempt to supply more oxygen to it and improve its effectiveness. When I harvested the fish plant growth continued for some time(about 2 weeks) before defciency showed up. This is probably due to excess nitrate stored in the water as well as continued solids processing by the worms.

I do know that worms produce ammonia as a waste product and that if it gets too high they suffer just like fish do. They also definately have lower tolerance to dissolved oxygen than a tilapia does. A sudden algal bloom killed my worms, but I did not lose a single fish.

[bigdaddy]

Hi Ravnis,

Thanks for the info

Do you know what caused your algal bloom?

From what I've read Tilapia would have to be about the most tolerant fish around to poor water quality,Is that correct?did you have any other fish species in your system?

That's interesting,your worms died and your fish did not.What you are saying about the ammonia... makes sense.

Cheers.

[Ravnis]

I have been experimenting with greenwater, but it has been 100F + temperature and the algae growth expanded exponentially and then suddenly died off depleting the water of oxygen. I had to run the pump continously to bring the oxygen levels high enough that they did not float at the surface.

I personally think tilapia are the ideal beginner fish. Really dont have to even cycle the water with them. Just have to be careful not to base all your information on their performance and understand that they are kind of unique in the fish raising. Not worth a fine though.

Barramundi have started to show up in grocery stores over here. I'm keen to try some after reading about them on this site.

[bigdaddy]

Hi Ravnis

When you try your barramundi,let's know what you think of it.

How much does it run over there?here it runs about $17-$18 a kilo(roughly2.2 pounds)

Unfortunately tilapia are illegal to raise over here,in most parts of Australia,large fines apply(up to $10,000),if you are thinking about raising barramundi the water quality needs to be very good.Jade perch are often recommended as a good beginner fish over here with tropical water temps.

Where are you? I'm in South Australia and it's freezing down here, about 9C wet,windy and miserable.Going for a top of 13 C Brrrr.We have a temperate climate with temps well over 100 F in the summer on quite a few days,generally dry summers and wet winters.

Ha Ha I just read your signature I must be very,very wise then.

Cheers.