Vermiponics - Aquaponics Without Fish

[Sue B]

Hi

Hmmm ... yes there are traces of Cadmium ~ 0.65mg/kg, Lead ~ 0.61mg/kg, Zinc ~ 0.010% and Mercury ~ < detectable level.
Do you know if they, in the above proportions, will be harmful?

I will investigate using separate containers for tomatoes, using expanded clay balls. It will certainly free up the area for other plants. I will also probably also need to find another source of potassium and phosphorus.

[GaryD]

Hi Sue,

In my mind, there is no acceptable level for things like heavy metals in foods.

The other problem with the use of substances which contain such elements is that they will build up in the organisms housed in an aquaponics system because of the "closed loop" nature of the process.

You can add "clean" forms of potassium or phosphorus to offset any deficiency.......or you can run your system at around pH 6.5 so that what potassium and phosphorus is in the water becomes available to the plants.

There are various sources of such nutrients including Seasol.....or even hydroponic formulations made specifically for fruiting plants.

Gary

[Sue B]

Hi Gary

Thanks for that. I think I'll replace the water in the tank which will dilute the elements greatly and use Seasol in future. Fortunately here in Darwin there is no water shortage or restrictions.
I guess the potassium and phosphorous have been available to the tomatoes as they are now fruiting madly. I've removed some that developed black spots on the bottom - blossom end rot? Not sure what it is as the spots are not actually where the flower was.

One of the many reasons for using vermiponics rather than acquaponics is that I can change the water without any problems and continue on :-)

[GaryD]

Hi Sue,

One of the many reasons for using vermiponics rather than acquaponics is that I can change the water without any problems and continue on :-)

What are you feeding the worms? Your system will be reliant on nitrification to a greater extent than you possibly realise.

Any photos?

Gary

[Sue B]

Hi Gary

The worms are fed fruit and vegie scraps that are put through a blender, frozen and then thawed.
The system also still has a softball sized wad of vermi compost suspended in a stocking in the tank which is replaced approximately weekly.
Whenever I have had to change the water previously I have also added a concentrated bottle of Maxicrop.
I'm aware that my chemical knowledge is limited and have found it difficult to obtain any commercial method of testing for nutrients. It has very much been trial and error.

No photos yet but must do so soon. Actually we've eaten quite a bit of the produce already :-p.

Sue

[GaryD]

Hi Sue,

The worms are fed fruit and vegie scraps that are put through a blender, frozen and then thawed.

Do you bury the scraps in your grow beds?

I assume you have a "fish" tank (with no fish) where you source water for your grow beds.......correct?

Gary

[Sue B]

Hi

Yes, I have a 650lt water tank which cycles into the beds.
The scraps go into the worm farm suspended over the water tank which drips into the water.

I've also had a look at worm wicking beds after reading your post and might try that out too.

Sue

[GaryD]

Hi Sue,

The scraps go into the worm farm suspended over the water tank which drips into the water.

Are you pumping any water through the worm farm? If not, you're probably relying on the leachate that drips out of the vermicompost.......and that's of limited nutrient value. To get the best value out of your castings, you would be better off to put some castings into a bag and suspend it in the tank.

Even better, would be for you to take some castings and put them into an aerobic digester (a plastic drum in which you place an air stone). Aerate the castings for a day or two (adding anything that might be lacking) and then remove the air stone and (once the sludge has settled out) decant the nutrient-rich liquor and pour it into your 'fishless' fish tank.

We might need to see if we can dig mornings up.......he's doing what you do but on a commercial basis and I'm sure he'd have something useful to contribute.

Gary

[Sue B]

Hi Gary

Yes I do put castings in a stocking and suspend this in the tank. I also tip water into the worm farm from time to time - not pump. I thought pumping might be too much drainage/leaching of the worm's bedding. Softy that I am :-}.

Sue

[mornings]

It's been a while since I've posted on my system (been a busy summer with berry crops).

I'm in the process of converting my system to a constant flow pump rather than flood and drain. However, I'm keeping my gravel in beds. Most of this is in preparation to find out what my worms can actually produce in terms of nutrient and growing environment (including growth regulators). Once I know that it really will work, that the nutrient base is whole and I have the knowledge to manipulate worm feed to attain the ideal environment, I will likely tear the whole system out and start over again with contant flow, floating raft system. This last is purely for economics -- I don't find that gravel is better or worse than floating systems, it just has to do with what I want to grow and the costs therein.

Over the last months I've been besieged by a number of problems that have little to with the principles of "vermipomnics", but the problems of leaks, water temps, air temps, evaporation, and green house stuff. These factors are also affecting what my final system will look like.

I am of the opinion now that if vermiponics means keeping worms and plants in the same physical system, they are better separated. There are simply too many conflicts between worms and plants and too many compromises to make (and, I believe these are minor compared to fish and plants). None of is to say that there is any thing wrong small backyard systems having plants and bio-reactors together, they are still efficient in spite of these problems. But larger systems, in my view, should be separated.

I have in mind to have separate facilities for worms and plants. My plant system will look very much like a hydroponic operation where I will add my own organic nutrient from my worms. I find that hydroponic operations -- for growing efficiency -- beat aquaponics and vermiponic hands down. Too, there is a huge body of knowledge and decades of experience to exploit.

On the worm side -- obviously I still have a great deal to learn -- I intend to run water through a gravel bed with worms contained. I'll feed the worms inputs I grow on my farm. I'm going to experiment with using a reverse osmosis filter to take all nutrient out of the effluent water in a, more or less, concentrated form (which will be applied in the hydroponic system).

If this works out well (that is still a big "if" as I am once again plunging into uncharted waters) I may even consider bottling the vermi-concentrate to sell. There seems to be a world of people who are doing hydroponics (with chemicals of unknown or origin and even content . . ugh), people who would like to use organic nutrients, people who haven't the interest or inclination for fish or worms.

I assumed this would only make sense for a larger system but I've have two co-hort worm enthusiasts who have expressed interest in finding a way to do this separation on smaller systems, I guess to overcome some of the problems of growing worms/fish in the same system with plants. We'll see.

M