It seems there is a lot of evidence of the vigorous and happy fig trees growing near the cement structures. The Alma sisters come to mind from the yesterdays post.
Many people add the dolomitic lime to the soil to correct the soil acidity.
I have discovered that it is not easy to find the proper lime while the cement is freely available at any hardware store.

I was thinking to make small gravel size pieces out of cement and add to my pots.

Any suggestions, thoughts, for or against this?

I checked the formula of the cement and it seems there are no chemicals added so it should be safe to use.

I meant the basic builders cement that is available everywhere.
It is lime based.
Please let us know the test results and thanks!

Here is a link about how the cement is made :
http://www.buildeazy.com/newplans/eazylist/cement.html

It starts as

1.) Limestone is taken from a quarry. It is the major ingredient needed for making cement. Smaller quantities of sand and clay are also needed. Limestone, sand and clay contain the four essential elements required to make cement. The four essential elements are calcium, silicon, aluminum and iron.

2.) Boulder-size limestone rocks are transported from the quarry ... and so on.

Basically, in theory, it contains all the elements the figs need.

Lime should be readily available in So Cal.

No point in having to use cement,
unless you want to experiment.

Jack,

The HD sells lime on the East Coast only.
If I need lime, I have to drive to a quarry.
If the cement works the same way, it would be more convenient for me.

Maybe one of the hundreds of garden supply stores or nurseries in your area.

More than HD out there.

A bag of lime would be far more convenient for you
than a bag of cement.

Check with farm supply stores. I buy lime by the ton. I also pore cement in several states the raw materials vary. They are made from limestone, granite, Sand, river rock, and Portland cement. Portland Cement would be the ingredient you are looking for but is much more expensive than raw lime. I'm sure I would prefer buying lime or hydrated lime in stead of concrete. I would check my ph to see how much lime I needed. IMHO there are more benefits to planting near concrete than the lime, nematode reduction, moisture, fewer plant root or chemical warfare from plants pressure ,equal to a herbicide strip. Mulching a large area would probably be more beneficial than using concrete or Portland cement. I'm sure someone could explained it much better than I can. If you already have areas with concrete by all means use them. Like FMD receives benefit with the Alma sisters but it's not just the concrete that releases lime that benefits the trees. There are many other things that play in to it.

I am not sure of your location in zone 10 southern Cal. But doing a search on Homedepot's site listed 50 stores within 50 miles of LA. Checking for lime at the store in the center of those found lime was not available in large bags but was in 6 lb bags.

http://www.homedepot.com/p/Espoma-6-75-lb-Garden-Lime-100508617/203192761

They have 3 bags, Aisle SL, Bay 004

I use caliche which is basically limestone. It makes up the majority of subsoil here and in many western states. If you know what to look for it's just laying around or exposed in many road cuts. This is the soil type that figs naturally grow well in and is found in much of their native range. I'd bet there's a gazillion tons for free in Southern CA.

Hi,
Be informed that fresh made cement releases a lots of heat - so if you use cement use just a cup per tree in ground - don't use in pots.
If you have an already made cement, that surface will attract and store the heat from the sun, and that surely is of a great benefit to any figtree.

We have decomposed granite for our soil.  There are huge boulders here, and you can almost watch them decompose.  Very easy to chisel shapes in them.  Not sure how much lime is in them, but the soil drains almost too well, so our figs need more water than soil with a little more clay content.

I've seen huge cracks in cured concrete from tree roots, including house slabs, so be careful planting too close to cured concrete, and give the fig tree's gigantic root system the respect it deserves, or give your home the respect it deserves by not planting a fig near concrete that you intend to dwell on for a few years.  Fixing a cracked slab is not cheap. Trust me, I know.  Been there.  I worry about those Alma twins... actually not the twins.  The pool and concrete surround.

Just saying...........  be cautious.

Suzi

Thank you everyone for your input!
I am sorry for not being more clear in my first post but I never meant to add the cement to the soil in the powder form, straight from the bag.
I meant the small pieces of the cured cement. Of course adding the powder to the potting soil will do more damage than good, I was not even assuming anybody would do such a thing.
I believe I should have used the term 'conrete' instead.
But thanks for the warning!

As Suzi mentioned, the fig roots like to grow into the concrete and hence my question.
Also, my intention was to use it in containers.

Jake,
Thanks for the link. I have bought that particular lime, you mix it with the soil and it dissolves quickly.
There are two things with it that I do not like.
It is not cheap if you need a lot (the cement is cheaper ) and I do not know how much it stays in after the frequent watering.
I like to have the ability to add the lime on top of the pots like the Belleclare owners did.

Fignutty, I will check the caliche. Although I live not far from a HD and would like to look into adding the concrete further .

Chunks of concrete in potting mix isn't going to be very effective. Not enough surface area. Maybe if ground up it would be effective. One lb of finely ground limestone would be as effective as a ton of concrete chunks.

The caliche won't be found in stores. What I use is mostly powder and is probably 50-90% limestone.

Decomposed granite is volcanic in origin. It's about as infertile of a parent material for soil as can be found. It's very low in calcium. Caliche is found in dry climates in soils derived from sedimentary rocks like limestone. The later being made of sea shells and such and very high in calcium.