In my rainy western WA climate we use it yearly & every 4th year dolomite lime on grass & our vegetable beds because our soil is very acidic. The rain washes it right out over the course of the year, so reapply.

Calcium carbonate is lime without the magnesium of dolomite lime.

Best to apply in fall to let it work into the soil by rain. Excellent for all your cabbage family plants to help prevent club root. Tomatoes & peppers also benefit. I put 1 cup in each planting hole along with a handful of organic fertilizer & mix up before transplanting. If your tomato soil is too dry it can't use the calcium carbonate anyway, so mulch also helps to prevent the blossom end rot I think you mean by the cat smiles.

Skip putting in compost as it really just wastes it & can interfere with composting process.

Lasts for years as long as you can keep it dry.

Not cat food. I don't know about grout usage.

Also known as agricultural lime, but not the caustic slake or hydrated lime.

Any muddy sour smelling area is sweetened by the sprinkling of it. Works well in the chicken coop under the litter if you don't use too much to make it dusty. Avoid breathing the fine powder.

Catfacing is different than BER, so I think your advisor might have been a little confused or just mistaken. Catfacing is usually caused by cool & cloudy weather particularly cool nights while the plant is blossoming, sometimes by blossoms that sticking to fruit, by cool nights during the bloom period, by the availability of excessive N, and sometimes because of mild exposure to broadleaf herbicides.

CaCO3 is often listed as a potential cure for BER, but that too (BER) is most often a physiological disorder (plant can't move enough Ca through the nutrient stream to keep up with Ca needs, even though Ca is present in adequate amounts in the soil and soil solution), rather than a nutritional deficiency.

Additional CaCO3 would only be helpful if there is inadequate Ca available or if the Ca:Mg ratio is far out of balance AND soil pH is low. Used any other way it's far more likely to be limiting than a benifit because too much of any singular element can be as detrimental to growth as a deficiency (see "Liebig's Law of the Minimum").

Al

Your plant need Calcium and Magnesium, in balance, to produce good fruit. Catfacing, what you are describing, is a weather related problem caused by cool, moist weather rather then a soil nutrient problem. Blossom End Rot is caused by a soil nutrient problem, and the cure for that is a good, healthy soil that is evenly moist but well drained.
You need a good, reliable soil test to tell you about your soils pH and the balance between the Calcium and Magnesium and then add either the calcitic or dolomitic lime needed to correct any problems. Never just throw some CaCo3 or any other nutrient source on your soil without some kind of guidelines about how much since it is easy to throw the soil out of balance and create even more problems.

Here is a link that might be useful: When good tomatoes go bad

I live near an oyster plant and one year a guy doing some garden work said I needed some calcium carbonate because my tomatoes had "cat smiles"
I went down to the calcium carbonate store and all they had was something like 50 lb bags (the smallest)
I've been sprinkling some across all of my beds each spring, but is there a better use of this stuff?
Will it help in the compost? Should I put some into planting holes? Can I feed it to the cats? Use it to grout tiles?
Any ideas? Nancy

I think we're playing telephone telephone!
I didn't say anything about BER in my OP. I was just asking about uses for the Calcium carbonate (ground oyster shells) in my garden.
I can't afford soil tests on 8 different beds that have been filled at different times by different places!
Nancy

People are talking about blossom end rot because that was how the term "cat smiles"that you mentioned was interpreted. After that, it just kind of went off the rails. We do that around here.
P.S. I'm not so sure you should feed your cats lime.

Nancy - your post left it unclear whether your plants were ACTUALLY suffering from cat facing or BER because the prescription your guy doing garden work gave wouldn't have an effect on eliminating or reducing the the cat facing, but it's possible that it might have an impact on eliminating BER. He's mixed up somehow, and there is no way to determine exactly how.

If you read carefully, you'll see the general consensus is that you're much more likely to introduce limitations than to improve soil health when you start adding elements or compounds to specifically increase the availability of singular elements in your soil w/o a soil test or very strong evidence that those target elements are indeed deficient. THEN, it's important to know WHY they are deficient because under certain circumstances adding 'more' does not = increased availability; and adding 'more' could DECREASE availability of other nutrients.

For example - if your soil is NOT Ca deficient, adding excess Ca can create an antagonistic deficiency of Mg. Additionally, if your soil cannot realistically support the increase in pH caused by the added CaCO3, it would make other nutrients, primarily the minors, less soluble and increasingly unavailable as pH rises.

Also, if we moved forward on the premise that what you or your gardener guy said about a lack of Ca causing cat facing was true, the entire conversation would then be pertinent to your issue because it would mean that insufficient Ca in the nutrient stream would also be to blame for that issue, not just BER. We now know it's NOT, but the notion still needed to be dispelled to arrive at an answer that would mean anything to you.

After distilling, you now know that the CaCO3 you're supplying isn't going to prevent cat facing, and only in certain cases might it cure BER (in case someone is still confused between the two different maladies); AND, it's not a good thing to add things to your soil and hope, without a good understanding of the far reaching implications.

Al

I wonder if lime/calcium carbonate/oyster shells will benefit your soil.

Rather than make a major oops with stuff you can get for free, contact your county's University of CA Extension Service office to ask what the prevailing pH is in your region.

Here's the page with contact info for San Mateo/San Francisco counties.
http://cesanmateo.ucdavis.edu/

Here is a link that might be useful: contact info for San Mateo/San Francisco counties

Good idea, Jean - the more knowledge we have the better armed we are. Cat facing is a common cultural problem in the SF area (dear friend in Fremont as witness) because of the cool nights & damp marine layer that comes rolling in almost every evening, but it would be interesting to learn what UCD offers.

Adding CaCO3 would only be appropriate if all three of the following were true: The pH of the soil is low enough to support the rise in pH the CaCO3 will cause, there is an ACTUAL Ca deficiency, and the amount of Mg in the soil will support the increase in Ca w/o the added Ca creating an antagonistic deficiency of Mg.

If the pH WON'T support the added CaCO3, and Ca was actually deficient, and Mg was there in ample amounts, gypsum (CaSO4) would be the drug of choice.

It's also possible that some combination of CaCO3, MgO (magnesium oxide) or even MgSO4 (Epsom salts) would be most appropriate depending on pH and the Ca:Mg ratio in the soil.

I understand that NJ doesn't want to do soil testing, but it's still important to recognize that without basis for adding the CaCO3 it's much more likely to be limiting by any of several mechanisms than not.

Al

Catfacing is caused by the factors as has been described in other posts above -- cool weather during bloom when anther(s) stick to the forming fruit.

Calcium carbonate, as has been explained, isn't involved in catfacing.

And BER is because the calcium doesn't make it all the way to the caboose -- the blossom end of the fruit. May be calcium shortage in the soil *but* much more likely to be erratic moisture availability to the roots.

But my comment was directed solely at OP's soil. Much of CA has alkaline soil to greater or lesser degrees.

Garden books commonly describe soil pH variation but then go on to offer the recommend management/preparation -- usually contains comment to add lime or calcium carbonate or wood ashes or crushed oyster shell or similar stuff.

That's often a seriously nasty suggestion for many CA soils which are already alkaline or nearly so.

While living in Long Beach, CA, I saw an organically run community garden plot seriously damaged when the gardeners added wood ashes around their seedlings. Dead was the response. I image the gardeners were puzzled why such a recommendation -- published in so many books and magazines -- killed their plants.

And, if one has alkaline or nearly so soil, one avoids wood ashes even though they're widely recommended for adding potassium.

SoCal soils don't need wood ashes for whatever the reason. Perhaps OP's Bay area soil is similar. Pointless to learn the hard way.

(putting soap box away -- )

FWIW - I was just briefly acknowledging your good idea, Jean, then moved on to further address the OPs predicament. I don't see any areas of disagreement.

Al

OK, I'll add water and turn it into a sculpture! Or dump it out in the field . Nancy

Wasn't disagreeing. Was on a roll on one of my hot topics. Figured I could put all the facts in one place.

be careful on calcium to magnesium ratio...read somewhere it should be 5 or 6 cal to 1 mag...the indian

Re the cat smiles. We often have cool foggy nights here and have had a few cool foggy summers! I'll bet that was one of them! Thanks, all! Nancy

50 lb of lime really isn't that much, and in fact your 'sprinkles' may not have had much of an effect at all. If it turns out you don't need it, it can be spread thinly over lawn and garden (or give away the bag in Freecycle, Craigslist etc.) and don't buy any more.

Somewhere on the web will be a calculator for lb of lime required for x sq ft. to change the pH by x amount, and it takes a LOT.