For our potting media we add course inert perlite, we add pelletized limestone for pH and Calcium. Would there be a point in adding limestone gravel for outdoor potting media? Could be a long term source of calcium. Could add some weight for better or worse.

Any thoughts on this?

I've always wanted to do this but I haven't found a source of limestone gravel locally.  There have been some previous discussions on the forum about this.  I believe the Belleclare nursery folks used to recommend putting down a layer of limestone gravel over the top of their fig containers.

Make sure you understand what your soil pH is before you start trying to alter it. As a fig newbie, I'm a little confused by the prevalent "figs prefer alkaline soil" messages because it seems most formal documentation I see online suggests a slightly acidic pH of 6-6.5. Adjusting soil pH too high can high block absorption of iron and manganese.

Thank you for sharing.

Steve: I am like you and I have not seen any limestone locally too. I will go to the Home Depot this spring to see if they carry them. 

Best,
Tam

I have been coating the top of my pots with limestone and have gotten very good results. Added benefit is it keeps the weeds down and insects don't seem very fond of it either.

Blake, there are tons of pictures of fig trees growing straight out of limestone in their native habitat so I don't think some in the pot will hurt anything. I found after adding it my trees took off.

I would check how much calcium is in your water, here my water is full with Ca so i dont add lime.

Why not put directly fertilizer ? if your goal is to feed the tree.
You could use pine bark as mulch upon the dirt .
On the "Pont du Gard", there are fig trees growing - it is an old Roman brigde in southern France.

I appreciate the input and the teaching. If there’s one thing I’ve gleaned thus far about figs is that they are highly adaptable. They can survive and even thrive in a broad range of soils.

With so many cultivars of ficus carica coming from wide-ranging environments (soil conditions) it makes sense that some would develop a preference for certain soil conditions. Just like some cultivars are hardier than others.

But I really am curious about choices the collectors here make and why they make them, especially with regards to soil chemistry.

When I read a reference to Belleclare Nursery in Plainview, NY suggesting a layer of limestone gravel on top of figs, it got me thinking. I wonder is that because:

1)      They think all figs prefer higher pH soil?

2)      Maybe it’s just the cultivars they sell?

3)      Maybe it’s because the soil in that area is very acidic and the limestone is needed to reach a more neutral pH for the figs? (Check any number of Long Island area lawn care service websites and they all speak to regular application of lime in order to balance the soil pH for lawns.)

I’ve developed a theory… Maybe the gravel suggestion is less about soil pH (unless you’re dealing with soil pH below 6) and more about a different set of benefits including:

1)      Improved drainage

2)      Reflect light and heat up to the plant

3)      Retaining and radiating heat to aid the ripening process

4)      Encouragement for roots to dig deeper to find nutrients

5)      Assist in water retention

I think #2 and #3 are particularly import for the many people here with cooler temperatures and shorter growing seasons.

No doubt soil pH and mineral content is also going to have an impact on taste so maybe that’s at play here too. As I learn about more about figs it seems there’s a lot to be learned from the practices of growing grapes for wine(?).

Again, I sincerely appreciate the input of this forum as I learn about figs. 

Ed,
I have grown cuttings in 50% Granular limestone without any major issues. It was only a test, but it can be done for potted culture. The Granular limestone can be be rinsed initially to flush out the dust and reduce the pH. I've measured a 8.9 pH in an agitated Dolemite Limestone solution, with water at 6.9 pH.


Blake,
Adding small amounts of Dolemite limestone to soil only slightly increases the pH.
The Bellaclaire Figs were grown in Peat based potting mixes which typically would benefit from an increase in pH, but by adding Granular limestone (larger grain) as a topping they actually increased the pH less, but increased the Calcium and Magnesium levels. Even adding yearly limestone applications to my garden soil has only slightly increased my pH less than 1 point. In potted culture increased watering will flush out the limestone and decrease the pH quickly until the pH levels approach that of the water.

The increase in pH is much higher when using processed Lime products (quick lime, Hydrated lime, etc) which should not be used unless you are experience with their application, they are up to 15 times more potent that Pulverized Limestone, very caustic and will cause plant damage if not used properly.

Your list of added benefits may all be possible.

BTW,  I add 1 cup of pelletized or pulverized Dolemite Limestone per 5 gallons of potting mix, with 1/2 cup added monthly for 3 months the ratios and mix are described here... http://figs4funforum.websitetoolbox.com/post/show_single_post?pid=1278563825&postcount=16 .

I put some crusher run in the bottom of my cups...observed that the lime dust does leach out and form a chalky crust in bottom of cup...thought that might be a problem for drainage and repotted. I usually mix in a handful of crusher run into 1g and larger now; hard to say whether it benefits are not.

Rick - what is 'crusher run'?  Some type of crushed limestone or gravel?

If you are looking for gravel, most block companies or stone places have limestone screenings.  It's basically very fine limestone gravel. A place near me sells it for $16/ton (not a typo).

I don't know how much this would affect soil pH since I think limestone needs acid (rain is mildly acidic, or strongly in areas with acid rain) to dissolve and be chemically active...not a quick fix. If nothing else it would help with drainage and add weight if wind is an issue blowing containers over.

Funny, I was just pondering this the other day if adding screenings to mixes or in planting holes would be beneficial.

Crusher run is crushed limestone chips...smaller than gravel and usually jagged. We use it on garden paths to keep mud down.