Fish and seaweed as soil amendments.

[TeamTeke]

Hello,
I am a Florida Keys home grower with a few limited beds and 20-30 large containers (average 10-15gal). As a very active fisherman here I have an almost unlimited supply of fish, fish carcasses and sargassum seaweed. How can I use any to this for my gardens without a stinky mess?

Is the sargassum in any way beneficial to the soil.

[tuk50]

Hello, TT.........
I'm also an avid fisherman and use fish scraps ...
As far as I can tell there is no way to compost fish without smell.. so I usually just bury it at least a foot or so in my garden. As you may already know the fishbones are also very beneficial.
Another issue is to not put a lot in one hole.. I try to scatter it in trenches when I have a lot to deal with. As for seaweed I have no experience with the type you mentioned, but I use any and all excess plants from my koi pond and it is very good and buy gallon jugs of liquid seaweed as soil ammendments. Hope this helps somewhat and Welcome to tv.

[RayR]

Sargassum is used as soil amendment/fertilizer but like all ocean kelp, it contains high levels of salts which need to be leached out with fresh water/rain.

[Douglas14]

I don't know what kind of animals you have down there, but a neighbor buried fish scraps near his house, and had a serious skunk problem. I imagine other animals such a racoons would be attracted to it as well. Something to consider.

[Redbaron]

Hello TeamTeke,
I am in Oklahoma now, but I have lived and gardened in Florida and have tried both Sargasso and fish heads. They work incredibly well.

Make a fairly deep trench between your rows and fill the bottom of the trench with a thin layer of sawdust (3 or 4 inches), then with fish heads, then sawdust again. Fill the trench back in with soil, then a layer of newspaper or cardboard and lastly pile on the rinsed and dried sargasso really thick as a mulch. I also would throw grass clippings through the year on top of that and around my plants. (optional but it works)

The following year plant in what was between the rows and do the same on the area plants grew the year before. If you alternate like this back and forth in a few years you will have some unbelievable soil. I mean soil that puts the best TV Victory garden soil to shame.

[bower]

hi TeamTeke,

For growing in containers, fresh chopped kelp has turned out to be a great amendment to improve the soil moisture retention. I got this idea from a UN FAO page and tried it last year in my greenhouse containers and it really did the job. Also at greenhouse temperatures, those raw pieces of kelp broke down and were consumed during the same season, so this time I will use somewhat more kelp sushi in my mix, to try and keep the benefits going longer.

As regards raw fish waste, I agree it is best buried fairly deep and covered well, should not come in contact with the plant roots until there's been time to break it down, no good for containers. The cooked bones can be crushed or mixed in to container soil without any smell or bad effects. I also throw cooked fish bones into the compost with other kitchen scraps and it's not a problem, just cover the scraps with a layer of soil, fresh clippings etc.

[b54red]

I was once an avid fisherman with too many heads and guts to get rid of both fresh and saltwater. I experimented with burying them deep and planting tomatoes and peppers in the same spot but not so deep. The plants I did this with were somewhat stunted and didn't grow as well as the others in soil with the regular amendments of compost, manure and cottonseed meal. I did this many years and the results were almost always the same. The next year those spots were great so I think you should follow Redbarons' advice and let them breakdown well before planting directly over them.

[nativeplanter]

Originally Posted by b54red

I experimented with burying them deep and planting tomatoes and peppers in the same spot but not so deep. The plants I did this with were somewhat stunted and didn't grow as well as the others in soil with the regular amendments of compost, manure and cottonseed meal. I did this many years and the results were almost always the same. .

Interesting. I have planted right on top of the carcasses, and they have done the best out of the garden. I wonder what the difference is.

[b54red]

Originally Posted by nativeplanter

Interesting. I have planted right on top of the carcasses, and they have done the best out of the garden. I wonder what the difference is.

I probably had way too many carcasses in the holes. When I said I was an avid fisherman I wasn't kidding. I would usually be putting nearly a full 5 gallon bucket of fish remains in a nice hole and then filling it in and planting over it shortly thereafter. I was usually too tired after a long day of fishing and then cleaning the fish to dig multiple holes for the remains. I think it just took too long to breakdown and pulled too much nitrogen from the soil with so much fish guts in one spot. These spots would be very fertile the next year.

[Redbaron]

Originally Posted by nativeplanter

Interesting. I have planted right on top of the carcasses, and they have done the best out of the garden. I wonder what the difference is.

Most likely quantity. If what our Florida friend is describing is like I had in Florida, it is one heck of a lot of fish heads. So when all that protein starts decomposing it releases a LOT of nitrogen. Way too much, way too fast, for most plants. So to keep all that nitrogen from burning the plants, and also keep it from leaching away, you use sawdust to absorb it like a diaper. The wood decomposes slower and will release it at a more controlled rate the following year.

The only plant I ever grew personally that liked that much nitrogen right away was corn. I have just buried fish heads and then planted a hill of corn over them. That worked. But most other plants it would be too much. Remember he is talking saltwater fishing in Florida. The heads alone can sometimes weigh more than any whole bass or crappie or even most catfish whole. It can be a LOT of nitrogen and other nutrients released very quickly!


PS Looks like we both posted at the same time!

[Hotwired]

The indians used to toss a dead fish in with the Maze seeds. Bet they didn't have the amount of Mercury and heavy metals in fish that we have nowadays. The same with Kelp. I read a study about the chemical composition of kelp.... (found it). In 100 grams of Kelp there is 12mg of Arsenic (0.12%), 2.1µg of Mercury, 30µg of Lead, 21mg of Aluminum (0.21%), and 3700mg of sodium (3.7%). Altogether, 4.1% of the chemical composition of Kelp is either harmful or not beneficial to your garden. I personally won't use kelp or organic fertilizer containing kelp. For me it’s an issue of long-term accumulation of contaminants. Adding a continual supply of tiny problems will eventually yield a large problem.

[bower]

Hotwired, I could understand the concern if you were sourcing kelp from a contaminated source. I don't think it is correct to generalize that kelp is a risk to the soil. I'd be interested in seeing the article you mentioned, since I didn't find it.

As regards arsenic, organic forms of arsenic occur in all seafood including kelp, but these forms of arsenic do not have the same toxicity profile as inorganic arsenic.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2137100/
In parts of the world where lots of seafood including seaweeds are eaten, there's no evidence of chronic arsenic toxicity in those populations.

I also looked into this last year for a friend who was assessing the risks of arsenic uptake by crops in soil where treated wood had been used. Organic arsenic is not taken up as readily as inorganic (such as leaching from treated wood). When arsenic contamination is a problem, it is a highest risk to be accumulated in root crops, followed by leafy greens, with the lowest or none detected in fruit crops such as peppers or tomatoes. Uptake of inorganic arsenic was minimized by enriching the soil with a lot of organic matter.

As regards other metals, it might depend where you are sourcing your kelp. For example:
There was transient radioactive iodine accumulation in California kelp after Fukushima:
http://www.scientificamerican.com/ar...alifornia-kelp
In Korea, kelps tested acceptable for the usual level of consumption as a food:
http://www.tandfonline.com/doi/abs/1...40040903532079
This company in Maine gives test figures for various seaweeds harvested wild for their food products:
http://www.seaveg.com/shop/index.php...d=21&chapter=1
The highest lead level detected was 1.7 ppm.
According to US standards, uncontaminated soil contains lead levels less than 50 ppm. http://www.atsdr.cdc.gov/csem/csem.asp?csem=7&po=8 There's no way adding kelp with 2 ppm of lead would be causing lead to accumulate to toxic levels in the soil. If the soil has 50 ppm lead, you would be diluting it with the kelp and making it less contaminated....

[Cole_Robbie]

Originally Posted by bower

assessing the risks of arsenic uptake by crops in soil where treated wood had been used.

The one study I read about that grew root crops in a media of treated lumber sawdust was able to just barely get the arsenic level above government recommended safety levels in the very tip end of the carrot or radish, the part that people typically cut off and do not eat. I think the sawdust they used was from the old treated lumber that had actual arsenic; the new stuff is arsenate.

[Tonio]

Hotwired, I would appreciate the source of your information.

RayR, interesting info/link - thank you.

T

[RayR]

Hotwired, you can't make a generalization that because Kelp contains things like Arsenic, Mercury and Lead that means it is poisonous to you or your garden since all those things are naturally occurring in even uncontaminated soil. A lot depends on how much in ppm's, but more importantly in what form, whether organic or inorganic.
The Arsenic found in Kelp is in organic form which is considered far less something to worry about than the man-made inorganic forms of Arsenic that are poisonous.
Inorganic forms of heavy metals or other minerals that are considered poisonous don't occur very often in nature because they end up bound in compounds that are pretty harmless in the concentrations they are found.

Sometimes man even mimics natural processes to neutralize the inorganic poisons that he creates. Here's a good example of how lead contaminated soils can be remediated with phosphate minerals turning lead into a harmless compound.
Remediating Soil Lead with Fish Bones