I once heard that clam shells were ground up and given to chickens to hardden the shells of their eggs. I belive they are very high in calcium and can work really well in a tomato patch. Now 15 gallons that would be a lot of help for lot of tomato plants.

Ground oyster shells are used for poultry rather than clam shells. It would take a veeerrrry long time for clam shells to break down to the elemental form required for plant uptake. You can still add the shells to your soil, but I wouldn't espect them to provide the calcium your tomatoes need.

By the way, I hope you did something with those crab and lobster shells, too! Good stuff!

I know of one use for them, if you plan on planting any bulbs this fall, crushed shells are a great deterrent for tunneling animals that would love to enjoy a delicious meal of your bulbs! You can sort of insulate the bulb in a layer of crushed shells, and when their little claws scratch against the shells they will get irritated and go the other way.

Thank you all for your thoughts. All seafood residue was shreaded. I called a friend who follows Rodale to the letter. They got back to me and read from a book published by Rodale. From memory it stated that: shreaded shells contain Chitin, an anti-fungal, large amounts of calcium, and many micro-nutrients. Apply at the rate of five pounds per 200 square feet. Add bloodmeal to encourage activity.
A side benefit of discouraging moles and voles would be helpful. Thanks again.

I just want to be invited to your next family reunion. That sounds like good eatin'...cousin.

tj

While I would tend to agree with just about anything Rodale publishes, I have to wonder about this. I'm currently renovating the back yard of my in-laws house and I've pulled about a dozen 5 gallon buckets of clam shells out of the yard so far. None of them appear to be too degraded other than the fact that they are all sun-bleached. These shells have been in the yard since before my father-in-law sold his last boat in 1981 and gave up clamming. How much could they be contributing to the soil if they're still around more than 25 years later? How finely did you grind yours up?

I use a Sears 9 hp chipper shreader recently picked up at a yard sale cheap. When shreading I throttle it down to near idle. Not too dusty that way. The shells wound up to be 1/4 inch and mostly in a 50/50 mix of pieces and dust. About 7 years ago I had added clam shells just broken up by walking on them and dug them into the garden. Over this time I noticed when tilling that the shells seemed to be disappearing. Some unbroken shells still remain. It may be that breaking or crushing gives better access to the nutrients. Lobster and crab last about 1 year until gone.
I started fall preparations and have added the shell material. Five gallons does not go very far at five pds per 200 sq. feet. If all that is accomplished is to stop or slow mole activity, I will be satisfied. I will do a soil test before planting. I have access to foundry slag and may try some of it. Might be hard on the chipper.
As a side note. Charcoal effectively reduces water related wilting. Try it with potted tomatoes to see what I mean. My rubarb has always had water related wilting issues, but not this year. Cucs like it too. A little goes a long way. Hope this helps. Best regards to all.