Anyone else using shell in their beds (coquina)

[byuind]

My wife got the final say and now all my beds have sea shell as ground cover here in St Augustine.

I will admit it looks great and makes the colors pop quite a bit on all her flowers. 
 

what I am looking for direction on is fertilization. I’m theory the granular fertilizer should make its way down to the soil one spread on top of the shells, but I also can see that the natural cup shapes can probably keep plenty of that granular from making its way down to the plants with any regularity.

my biggest question is: anyone else have coquina beds? And if so, how agreeable have they been to fertilizer?

[Rivera]

Can't meaningfully answer your fertilizer question as I don't have even a fraction as many shells as you do, but I live by the beach and freely distribute seashells, sand dollars, and crab shells around the garden without concern.

I only crush and distribute them more heavily around plants that naturally grow in calcareous soils in a substantial portion of their native distribution (like Howea forsteriana). Probably also agreeable for plants that grow on and around limestone, though I could be wrong. 

It was also noted to me by someone much more knowledgeable than myself that calcium carbonate may feed beneficial nematodes. 

[byuind]

12 minutes ago, Rivera said:

Can't meaningfully answer your fertilizer question as I don't have even a fraction as many shells as you do, but I live by the beach and freely distribute seashells, sand dollars, and crab shells around the garden without concern.

I only crush and distribute them more heavily around plants that naturally grow in calcareous soils in a substantial portion of their native distribution (like Howea forsteriana). Probably also agreeable for plants that grow on and around limestone, though I could be wrong. 

It was also noted to me by someone much more knowledgeable than myself that calcium carbonate may feed beneficial nematodes. 

I had heard that the calcium itself could be very beneficial to the overall soil quality (mine is basically sand).

 

 

[ZPalms]

I’ve been thinking about it because I love sea shells just for the look of it 🐚 

[Silas_Sancona]

16 minutes ago, Rivera said:

Can't meaningfully answer your fertilizer question as I don't have even a fraction as many shells as you do, but I live by the beach and freely distribute seashells, sand dollars, and crab shells around the garden without concern.

I only crush and distribute them more heavily around plants that naturally grow in calcareous soils in a substantial portion of their native distribution (like Howea forsteriana). Probably also agreeable for plants that grow on and around limestone, though I could be wrong. 

It was also noted to me by someone much more knowledgeable than myself that calcium carbonate may feed beneficial nematodes. 

I can't say much about Gastropod shells ( Don't see why the wouldn't as well ) but know the Chitin-based Shells / Exoskeleton of Crustaceans like Crabs, Lobsters, Shrimp, etc do encourage certain soil- dwelling organisms to produce Chitinase which helps suppress bad nematodes.

Supposedly, plants like Beans, Avocado Papaya, Tomatoes apparently also produce good amounts of Chitinase as well:

Simpler of many articles related to the subject: https://www.weekand.com/home-garden/article/crab-shell-control-nematodes-18014408.php

[byuind]

9 minutes ago, ZPalms said:

I’ve been thinking about it because I love sea shells just for the look of it 🐚 

That’s why my wife went with them. I tried the mulch fight and lost… but I will say they look really nice

[Little Tex]

3 minutes ago, byuind said:

That’s why my wife went with them. I tried the mulch fight and lost… but I will say they look really nice

you should have put mulch under the shells as a final hurrah

[Rivera]

41 minutes ago, byuind said:

the calcium itself could be very beneficial to the overall soil quality (mine is basically sand

It could be. Sometimes an excess of one element can lead to deficiency when it comes to a plant's ability to uptake another, but it's not something I'm particularly knowledgeable about. For that reason, I try to give plants as much of what I think they evolved with as I can easily give them in my own crude way. Our California natives and Western Cape South African plants generally just get mulch, while exotics used to more fertile soils also get a balanced organic fertilizer. 

Some folks on limestone soils struggle with nutritional deficiencies in certain plants that don't naturally grow on such substrates.

I haven't analyzed my native soil (Pacific coast dune sand, and whatever it's been adulterated with over the years), but calcium is one thing that probably isn't lacking here. For palms, I'm more concerned with elements like iron, nitrogen, potassium, phosphorus, magnesium, and manganese. Maybe other trace elements as well. 🤷🏼‍♂️

Edited May 8, 2023 by Rivera

[Rivera]

26 minutes ago, Silas_Sancona said:

I can't say much about Gastropod shells ( Don't see why the wouldn't as well ) but know the Chitin-based Shells / Exoskeleton of Crustaceans like Crabs, Lobsters, Shrimp, etc do encourage certain soil- dwelling organisms to produce Chitinase which helps suppress bad nematodes.

Supposedly, plants like Beans, Avocado Papaya, Tomatoes apparently also produce good amounts of Chitinase as well:

Simpler of many articles related to the subject: https://www.weekand.com/home-garden/article/crab-shell-control-nematodes-18014408.php

Interesting!

It was @Darold Petty that educated me about some of the benefits of crab shells and organic gardening after sharing with me the story of his devastating loss of a mature Lepidorrhachis mooreana due to pathogenic nematodes. I didn't even know there was a fourth Lord Howe Island palm before visiting Darold's garden. 

Edited May 8, 2023 by Rivera

[D. Morrowii]

I have access to a mix of crushed coquina and sand that turns up along the shore in the Banana River in different areas. I’ve used it as the sand base for the potting mix I make and wondered about how it affected nutrient balance. It’s everywhere in the soil in my yard as well. I believe that calcium is an antagonist to boron. So it could affect how plants will uptake boron, I think? I’m just not sure how fast or how much calcium is released. As a rule of thumb I only put shells, rocks etc in as mulch around palms that grow in sandy shelly soils as @Riverasaid. Anything that likes rich, moist, acidic, humic nutrient laden soils gets organic mulch. I’m curious as to what others with more experience have to say though. 
I can say that I do seem to have a fair number of potted and in ground palms that occasionally show signs of boron deficiency. Its easily treated for the most part but I think its a slow process to fix at times. 

[ZPalms]

I'd be tempted to collect shells I put in the bed 😂

[Looking Glass]

I put them around Pseudophoenix Sargentii and they seem to enjoy it.   Granular fertilizer seems to stain the hell out of the nice white shells though.   I also put full size clamshells out there too, whenever I steam a bunch.  Could be too alkaline for many species though. 

[aztropic]

Looks great! As for fertilizing,be aware that some fertilizers (probably high in iron) will stain the shells orange and brown. I didn't fertilize at all for several years in my shell mulched beds because of that fact. 

 

aztropic

Mesa, Arizona 

[TomJ]

Collecting shells sounds great, but isn't there salt even after a rinse?

 

[D Palm]

You could use the fertilizer tree spikes if granulars making it down to the soil is your concern.

[Merlyn]

Fertilizers staining things brown is definitely an issue.  I have a bottle of Southern Ag Palm Nutritional spray, with Magnesium, Sulfur, Iron and Manganese.  It's a chocolate brown concentrate and is solid brown when mixed to spray.  I sneezed when I was filling a spray bottle, and splashed a teaspoon on some concrete.  3 years later and several pressure washings...and it's still stained brown!  I like D Palm's recommendation of the spikes.  They are expensive for the amount of fertilizer that you get, but might avoid turning all of the white shells orange and brown!

[byuind]

1 minute ago, Merlyn said:

Fertilizers staining things brown is definitely an issue.  I have a bottle of Southern Ag Palm Nutritional spray, with Magnesium, Sulfur, Iron and Manganese.  It's a chocolate brown concentrate and is solid brown when mixed to spray.  I sneezed when I was filling a spray bottle, and splashed a teaspoon on some concrete.  3 years later and several pressure washings...and it's still stained brown!  I like D Palm's recommendation of the spikes.  They are expensive for the amount of fertilizer that you get, but might avoid turning all of the white shells orange and brown!

what's the consensus on these spikes and root health? I have seen all these articles saying that they cause problems because the roots are only getting the benefit in the immediate vicinity of the spikes. I would, in theory, rake back the shells when I wanted to fertilize, but that would be a MAJOR pain. 

[Merlyn]

@byuindI don't really know the answer to that.  I suppose if the stakes were spread out they'd slowly dissolve out in the same way water spreads out if it drips into the soil.  Water spreads out in an expanding cone shape, as long as it isn't "tunneling."  And you wouldn't get root burn, because they dissolve slowly.  I guess I haven't read about any negatives of spikes, because they didn't meet my initial cost-benefit ratio. 

[Silas_Sancona]

13 minutes ago, byuind said:

what's the consensus on these spikes and root health? I have seen all these articles saying that they cause problems because the roots are only getting the benefit in the immediate vicinity of the spikes. I would, in theory, rake back the shells when I wanted to fertilize, but that would be a MAJOR pain. 

I'd say avoid them, for the exact reason you stated.. We generally have a little more clay in our soils here and i'd still never use spikes..

Use a slow release granular that you scatter lightly around the drip line of each palm, then rake it in through the Shell.. No need to rake back the shell and apply, ...Wayy too much busy work / over thinking it..

The major things that you have to be sure the plants are getting are things like your minors ..that the shells don't already provide themselves, and Potassium.. Soil there in most of FL is high in Phosphorus ..so you shouldn't need to add much -if any- more than what naturally occurs..  ...At least not 2 or 3X's a year.

Shells supposedly release some form of Nitrogen ..so you shouldn't need to dump tons of that on everything either. Small leaves from other plants that get trapped in the Shell will sift down through it and release N ..and other nutrients locked in them as they are decomposed below the Shell layer.

[D Palm]

I use tree fertilizer spikes because they are often on clearance. Work great for me. The products being unpopular is a plus for my wallet.