Use of soil in substrate..

[Samala]

Has anyone here previously tried to supplement their substrate with regular potting soil? Mind you I am suggesting the type of soil that can be had from the garden center, high in organics, low in that terrible perlite stuff that floats and causes a total mess.. no additional fertilizers. I'm wanting to try adding it to the substrate of my tanks to increase organics in the substrate and improve root growth. I'm particularly concerned about my turtle grass. Its growing, but not at the rate I was expecting after the length of time it has been in my tank.

I was thinking of getting the soil and soaking it in saltwater for an unknown amount of time to liberate any potential problem molecules from the mix. Any suggestions on time frame?

Any long term problems that could come up that I should worry about now? Beyond soil clouds of course after planting and such.

Ideas, criticism, 'you must be crazy' all welcome.
>Sarah

 

[Triterium]

Sarah,
In my mangrove tank, I added about 3 or 4 5-gallon buckets of garden soil. It is garden soil that i add a lot of peat and manure to every year. I mixed about half soil and half silica sand to a depth of about 6". I then covered it all with maybe 2-3" of oolitic sand.

I tried something similar in my indoor seagrass tank. The manatee grew very well (18"+) and the turtle grass did pretty well but i was far from impressed.

 

[Samala]

Peat, garden soil.. and manure...?! And I thought that I liked to play with fire. Manure Triterium, really?? If thats not organic I dont know what is. You must really have a big ol green love fest going on at your house with the greenhouse and all the, um, poo and such.

Um, anyway, thanks for the bits of advice.

I was just wondering.. what does it take to get turtlegrass happy enough to reproduce?! Its growing sooo slowly I want to pull my hair out. Light levels of 7 and 10wpg dont seem to impress it. Were you keeping it under MH? Maybe there's something other than light and substrate we're mising out on?

Time to go consult the mad scientist cook book.
>Sarah

 

[Triterium]

The turtle grass that i have that is doing the best is in filtered sunlight and a fairly new oolitic sand bed with nothing added. It has at least 6 leaves but they are only about 4 inches long.

 

[bigben]

hey sarah,

if i go this route and can't get a hold of some collected salt marsh mud or sediment from turtle grass beds, i'd probably only go with potting soil that does not contain any miracle grow or similar product, as that will obviously make it's way into the water column. i'm guessing the best bet would be a mix of pure soil, somewhat rich in clay, a small amount of biodegradable material, and possibly some laterite.

i'd be careful on the laterite, though, because as i told you before, i thought i remembered reading somewhere that iron diffuses from laterite much faster in high alkaline saltwater than in freshwater.

maybe someone can comment.

triterium, have you had any issues with algal blooms as a result of using that much organic material in your substrate?

everyone, perhaps the substrates we are using do not have the necessary bacterial symbiotics that these grasses require for successful growth? maybe the light intensity, water movement, oxygenation, alkalinity are all bigger issues than we really think? just tossing some ideas around that i know have been addressed to some depth already.

edit...i wish i still had the email that eric borneman sent me last year on this subject. we had some discussion on this subject, and he's been keeping seagrasses long-term for several years, though i'm not sure of he's currently still keeping them. unfortunately, i crapped my hard drive and lost the info.

 

[Triterium]

Ive had some diatom blooms but I had those before i set up the refugium with the manure. Since i added a big skimmer, the diatoms have not been a problem. Oh i almost forgot. I also stuck a bunch of fertilizer spikes into the sandbed

 

[Samala]

Ooh I like where this thread is going.. so the question is.. what are we missing? Is it organic content of soil, is it just light, or is it something more?

Triterium says..
It has at least 6 leaves but they are only about 4 inches long.

You too Trit? I've noticed that the newest leaves on my plants are not growing very tall either. I was thinking it was lack of light. How could the sun be driving dwarfed-growth? Maybe it is a problem of not having enough current! Halodule is known to grow taller and thicker in higher current areas, even current as supplied in uni-directional flow from a source such as a powerhead.

You mentioned that tank has 'sterile' oolitic sand.. that reminds me of the study I found from the IRL Smithsonian crew that compared the local mud as a substrate with blasting pit sand and found no difference in growth rates. (??)

Ben says
guessing the best bet would be a mix of pure soil, somewhat rich in clay, a small amount of biodegradable material, and possibly some laterite

Well, Ben, you'll love the local soil then. Have you discovered yet that its all clay around these parts? It is in Delaware at least.. though you are more up on the piedmont where it might not be so thick. After I took soil science I started hunting loam deposits and found a great one in my own backyard at the time. That soil produced a-mazing freshwater planted tanks. I feel it would be just as useful in saltwater, providing its not full of fertilizer or pesticides.

I havent heard the thing with iron leaching from laterite more quickly in saltwater. Not that I doubt its plausibility.. we are all fully versed in saltwaters corrosive abilities. Maybe Peircho, if he's out there, has an idea on this? I've only come across mentions that iron precipitates in saltwater more quickly and can become toxic more quickly.

Ben was musing about different things we arent meeting.. something about necessary bacteria.. do you think they need certain bacterial colonies for nutrient conversion? Like little nitrogen loving bacteria in their roots like legumes? Or maybe you meant an association with something like mycorrhizal fungi? I think we need plantbrain...

Are either of you familiar with the name Diana Walstad? She did some work with soil substrates in freshwater planteds.. might be worth a quick read if you can find some articles from her. I think she's the one plantbrain isnt really crazy about because of her use of saltwater references to apply to freshwater macrophytes. But we've got saltwater... (or I could be wrong)

 

[Harmsway]

Well I have no clear answer for you but let me take you on a different line of thought.

Turtlegrass may be found in the wild from Sebastion Florida on south, about 28 degrees latitude. This is clearly subtropical climate. I think this is the key more so then nutrients in this instance. A subtropical climate implies that the temperature normally does not dip below 0 degree C. But that's not the point. The point is the mean water temperatures are higher.

Let me explain. Where I live now, north of Sebation tropical friut trees such as mangoes do not grow without human care. When I lived in West Palm a few years back, south of Sebation, mangoe trees were everwhere. You see climate is the difference.

North or South of Sebation ( Turtlegrass line ) I'm sure things such as nutrients, salinity, alkalinity and oxygenation are the same. The duration of daylight and water temperatures would not be the same.

Natural sunlight even filter may have increase temp enough to trigger growth. Just a thought.

I suggest pushing temp up as high as 85 degrees and see what happens.

Gene

 

[Samala]

Hmm.. climate is a possibility. But, what are the mean water temperatures in the southern half of the IRL that are so different from our tanks? Room temperature I would think is rather equivalent to subtropical temperatures.. 60-80F. I know my house rarely wavers outside of this range. I know the IRL runs higher and lower, but not by very much. I think the lowest I got in December was 52F and hottest in July/August was about 81F in good flowing, non stagnant spots.

Also.. I thought I read that seagrass was most productive during the more moderate water temperature periods of the year.. early fall.. late spring/early summer. But anyone's guess on how to apply that to a little grass box.. perhaps the rules dont apply at all.

I was really under the impression that it was salinity rather than tempertaure driving the break near Sebastian. Want year-round data on IRL data for various WQ parameters? My parents are volunteers with the Marine Resources Council's Lagoonwatch on the IRL.. check here.

Freshwater dumping into the system for storm water retention ponds and structure flushing kinda clouds the issue.. but this was just my understanding.

I know in the Chesapeake the demarcation line for eelgrass (analog to southern turtlegrass) and Vallisneria americana (a baygrass really) is noted almost entirely by salinity. A bit like comparing apples and oranges though.. and there is the consideration that the bay runs less turbid as the salinity increases.

Perhaps it is just this.. turtlegrass is a climax species. Once established they do well in most bed areas but getting them established takes some time. Halodule, Syringodium and the Halophilas seem to fill more of a role as pioneer species.. more the weedy varieties that are fast growing and almost invasive. Once they establish a good area and stabilize the soil the turtlegrass eventually colonizes if everything else is good. I have certainly seen that the Halophilas are quick colonizers.. new growth inside of a week.. shoal grass takes longer.. manatee even more so.. turtlegrass is just plain bratty.

>Sarah

 

[graveyardworm]

Sarah, I just noticed you put up some new threads, and so far I've read this one. I'm curious if you've figured out why the Thallasia was remaining so short, and if you have had better luck since this thread with getting it to spread? Currently I only have a single plant, I've had it since sometime in the late winter/early spring, so far no new shoots, but it does consistently send up new leaves which grow to about 15 inches.

 

[Samala]

I havent had any further luck with getting Thalassia to spread and I was dealing with a number of factors:

>Light
>Potentially starved of microbe populations (plants arrived bare root)
>Lack of proper organic content in the substrate

I am having much more luck with Thalassia seedlings that are being grown up using substrate from wild sites that already support turtle grass beds.

Hopefully those will grow to normal sized plants. I've got a few under the same light amount as I used before - with and without wild substrate and a few under natural sunlight with and without wild substrate. That might help answer was it light that led to the death of the plants before, or proper substrate.

And just perhaps its something I havent considered yet.

>Sarah

 

[piercho]

I have a number of notions about stuff you are talking about, but no concrete sources I can recall at this moment. I do think that Eelgrass and Turtlegrass are tougher to get going because they are more dependant on the microbe community in the substrate. As I recall, the flux of N into grass communities can be very high, and I have the notion all that fixing is occuring in a similar fashion to how it does with legumes on land. That is, the climax grass roots and N-fixing microbe communities are codependant.

As far as potting soil: soil first, then window screen, then sand. That way the lighter stuff won't work its way up. Roots will be all tangled in the dang screen if you are propogating from the tank, though.

 

[CELACANTHr]

Interesting! I am gonna hop into the "more flow" boat because of some stuff I saw in the keys on my most recent trip.
I visited 2 sites
site 1- EXTREMELY shallow, and very low almost unidirectional flow. I saw lots of sea grass...but the majority were very short. The only places where I saw tall grass were on hills or mounds of sand, where it causes the current to move up and over it...and thus the current was much more extreme than on the flat areas. It was really warm here (80-85)

site 2- It was a boating channel. It got very deep VERY fast, and it was extremely cold (<70), both of these probably because of the channel carrying in deep cold water...but IDK just a theory. Well every time a boat woudl pass it woudl cause some seriosu currents and even when one wasn't coming by there was some pretty strong flow. The water was really murky, so I don't think that 10 wpg is your problem sarah. The seagrass here (specifically the turtle grass) was HUGE!

IDK if this helps at all, but...