Wood chips as supplemental media experiment

TCLynx

I wasn't quite sure where the best place for this thread would be. I guess here unless anyone else things we should create an experiments section.

Anyway, I already wrote of this experiment starting in my Pee Ponics thread since that is the physical system that I will be using for this experiment.

TCLynx wrote:

Pee Ponics is being temporarily hijacked for some other experiments.
There are now three tilapia in the tank and I will be seeing how they respond to a grow bed filled with wood chips hooked to the system.

This experiment is for a couple of reasons.
1-I have been told not to use wood mulch in a system with fish but when I asked what was bad about it, the only answers I got were that cypress pine would be bad for plant growth. I've done a little searching on the subject and I know that some woods contain resins that could be bad for the fish. Hardwoods would be safer for the fish. I do know from experience that cypress mulch does not inhibit plant growth since I have used it as a hydroponic medium. I have also used our run of the mill random wood chip mulch as hydroponic growing medium. I will run some wood chips in this system and report back how the fish respond.

2-I expect that wood chips will have an acidifying effect on the system. I have too many shells in my systems and would like to see if there is a reasonable way to bring my system pH down closer to 7-7.4 rather than the 7.6 and up I currently have.

If the wood chips turn out to be safe for the fish and can help bring the pH of the system down just a little bit, I might try using them in moderation to grow things like sweet potatoes.

Expected drawbacks of the wood chips, they will rot and need to be replaced regularly. This could also be thought of as a benefit since the rotted wood chip muck out of a half barrel will likely make really nice compost and soil amendment. Wood chips will stay really wet so only certain plants will want to grow in them. They are pretty coarse so probably not well suited to much direct seeding or tender small seedlings. Wood chips will tend to tint the water a tea color but the maxicrop does that too. The fish don't seem to mind a bit of black water so I guess I shouldn't either.

Anyway, we will see how it goes and I'll let everyone know.
My basic wood chip mulch (free from local tree trimming companies when they are chipping in the neighborhood and need to dump) is mostly live oak (and other similar southern oak varieties) along with some palm, palmetto, occasionally some other trees mixed in. Leaves and fronds shredded too. If there is a section of pine in there, it is usually easy to avoid as the pine needles mark those piles pretty well.

I figured this experiment needs it's own thread since it is not pee ponic for the time being.
Will link between the two threads though
http://backyardaquaponics.com/forum/viewtopic.php?f=18&t=2534&start=305

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I cleaned up most of the planting from the pee ponic system.
Plants still in the system as of the beginning of experiment,
In the half barrel still full of river gravel,
One cherry tomato plant wandering off around the corner of the compost bin
One basil plant
One strawberry plant
In the top bed filled with shells,
Some straggly mint plants coming back to life.
In the half barrel now mostly filled with wood chip mulch (still has gravel in bottom and around drain fittings), Sweet potato slips and vines.

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There are three smaller tilapia in the fish tank, I attempted to get two femals and one male so perhaps they will breed but I hope they don't hurt each other.

The water tests before the change read
pH 7.6
Ammonia 0
Nitrite 0
Nitrate really high at least above 80 probably above 160 but I didn't do a dilute test to be sure.

Water has gone a bit murky after the change but I expect it will clear to a tea color in a few days.

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TCLynx

swanberg wrote:

Oooh, good experiment. I have access to lots of woodchips, too. Are you worried at all about pesticides/herbicides that might have been on the trees?

pasted from the other thread

I suppose this is part of why I'm doing the experiment.

Most people down here don't spend lots of money to spray trees they are going to have cut down by a tree service though. Spraying large trees isn't easy either. If people in my neighborhood are spraying large oak trees with anything, I expect I'd be having bigger problems with direct drift of the spray rather than any residue that might have worked it's way into the wood and still be on the wood chips.

And the wood chips I have in a pile right now have been there aging, weathering, and composting for 5 or more months at this point. Leaves other than palm fronds are pretty much unrecognizable now.

TCLynx

As far as any pesticides go, the bugs, in the wood chip pile don't seem to notice any at this point. I sometimes wonder if pesticides are why Florida has roaches large enough to carry off pets and small children but I try not to ponder too much on that and we call them pawmetto bugs here anyway.

Dufflight

This will be interesting to follow. Oak is also a good choice because they use it for alcohol storage. But only for a set time. If that is because of something that comes out of the wood and then stops or because after some time it starts. I've heard of people using the wrong try of wood chips for there garden and nothing growing there. Not sure what trees they were. Probably a native to Australia. I've got one tree in the back yard that manages to kill anything in its radius thats not lawn.

TCLynx

There are several types of trees that can have an inhibiting effect on certain plants near it. Walnut is a major one that produces junglow (if that's how it's spelled?) or something like that anyway. I think magnolia might have a little bit of that effect too. At least I notice that only some stray weeds seem to thrive right under the magnolia tree by our shed.

As to the oak barrels for aging whiskey and burbon and such. They are charred inside and I think there is something to do with the charcoal and wood absorbing some negative things from the spirits as well as lending a nice smoked flavor to them. I suspect that using them more than once would cause a major quality difference probably more due to the charcoal already being impregnated with the impurities. The wood aging will also cause more varriation in the integrity of the barrels since it is the wood swelling that keeps them from leaking yet wood breaths.
I just saw a documentary on spirits on history channel a couple weeks ago so this is all pretty fresh in my mind after that.

RupertofOZ

Here's a paper about a study done to measure the effectiveness of (white) cypress pine as an insecticide... particularly against termites.... (cypress pine posts are often used for this reason).... definitely seemed to have some affect...

http://www.wipo.int/pctdb/en/wo.jsp?IA= ... SPLAY=DESC

hydrophilia

Very interesting experiment.

Black walnut does inhibit a lot of plants from growing nearby, as you pointed out, TCL. An extract of the hulls (as my brother and I discovered as kids while washing walnuts) will drive worms out of the ground. Supposedly something in the leaves will drive out parasites: I did not believe this alternative medicine, but our horses drink from a trough under a small walnut and have no worms and have not been wormed in over a decade. Possibilities for ich?

Oleander is nasty: the honey is toxic, the leaves are toxic (at least to cows). I wouldn't use those chips.

I'll corroborate your info on oak barrels: I've heard similar info from winemakers around here. Some who have switched to aluminum (aluminium to some who aren't so lazy!) barrels for red wines use toasted oak cubes for the flavor.

TCLynx

The sweet potato vines in the wood chips have perked back up after their transplant but it's supposed to be really hot again today so I expect several parts of the garden to be a bit droopy.

The water is still really dark so I can't see the fish. No floaters at least.

Of note, the chippings I've usually gotten are from when people call in a tree service to deal with large trees that they could not cut up themselves. Most oleander can be dealt with had clippers and tied up to put out by the curb, I doubt people would spend big money for the tree service to come in and do that. If I ever notice anything that looks like oleander in the mix, I'll mark that part of the pile for some other purpose.

The chips I put in the barrel looked mostly to be from oak and palm.

A few things I expect in this experiment, the wood chips will probably break down rather rapidly and I'll have a grow bed that is more like filled with chunky compost and stays really wet. I expect any bed using such media will need have the chips replaced each crop or so (depending on the length of time the crop takes.) I chose to put sweet potatoes into the half barrel since they like wet and I figured the chips would be softer on the tubers.

Will take a sample of the water and test shortly though I don't really expect much change yet.

AlexP

you might end up with some interesting fungi growing.

TCLynx

I already get that with the chips on the ground, especially where they get mixed with the mushroom compost.

TCLynx

Ok, to update on the chip experiment.
The water is still very dark. Can't see the fish but no floaters and the food I've been putting in has been slowly getting eaten. (luckily this food is the kind that will float for days.)
The Ammonia and Nitrite tests still seem to be coming up 0
The pH tests are kinda tricky since the tint to the water could be skewing the reading or the pH could have dropped a little. At this point, I think the pH is still pretty close to 7.6 and the tint of the water is just making it look like 7.2.

TCLynx

Thought I should do a bit of an update about the progress of the experiment.

The water is a pretty dark brown color so it is very difficult to see the fish. It is already hard enough to see fish in a barrel on it's side tank in the first place but now add water that looks like weak coffee and you only see what floats.

This brown tint to the water has also had the effect of making pH test results difficult to trust. This system still has one bed full of shells, one bed full of river gravel, and one bed mostly full of the wood chips. I think the pH is still some where between 7.2 and 7.6.

I started with 3 fish in that tank. One was a rather small male like maybe 4-5" and the other two are probably 6" females. The small male is dead. I can't say for certain that it was not because of water quality (something in the water from the wood chips) but he looked rather beat up like perhaps he had mated with one of those females and she got aggressive before releasing them.

I drained the tank down a bit so I could net the other fish out and take a look at them. They seem ok. One looks a little beat up but they really don't look any worse than any of the other females I've put into tanks to breed. I topped the tank back up with clearer water from the main system. The water has remained a bit clearer than it was before but is still quite dark.

This morning I added an air stone into the tank. It will be really hard to tell if either of those females had been holding babies since they could very easily get sucked thought that small pump and I'd never know.

TCLynx

Here is a pic of the dead fish from that system. About to be buried in the compost pile. Had been dead a while as I of course couldn't see him till he floated up.

hydrophilia

TCLynx wrote:

It will be really hard to tell if either of those females had been holding babies since they could very easily get sucked thought that small pump and I'd never know.

How about a strainer at the outflow to catch any babies? I know it wouldn't keep them alive, but you could at least find out there are some in the tank.... I realize this is not a long-term solution, but it might be good as a temporary measure.

I wonder if the dark stain will eventually leach out with water changes...

TCLynx

I suppose I could just look and see if any body pars appear up where the water pumps into the top grow bed. Problem is the really tiny fry are almost impossible to see even when intact.

As to the color leaching out. Yes, it probably would in time, a very long time and very lot of water changes. I suppose one could pre-soak wood chips before use but I suspect that no matter what, they are going to tint the water through most of their usefulness in a system since they will decompose.

My tentative early conclusions about the wood chips. They stain the water too dark to be satisfactory in large quantities. They do not seem to create a strong enough acid effect in the short term to counteract strongly buffering limestone, marble, or shells as the other media.

I will continue the experiment for a while to see how the other fish survive so we can know which of the reasons not to use wood chips in the system are the best ones to site.

Backyard Aquaponics A place to discuss aquaponics

Wood chips as supplemental media experiment

Backyard Aquaponics
A place to discuss aquaponics