wow ! now i understand your concerns.  that's real clay !
i wondered why all your trees were in pots. now i know.

I agree with Bob:  I don't believe the claim.  The so-called tip says "Restrain fig roots and the tree will reward you with larger crops".  I think that's bunk.  You may be able to find some advantages to the technique described there in some very specific scenarios (just as you'll find plenty of disadvantages in lots of other scenarios, probably a larger set).  I can devise them too, just as I'm sure most of you can dream up specific scenarios where this would help to solve some problem.  But overall this claim is bunk.  IMO, it has not even got enough credibility to be worth trying to devise any experiment around the premise.

Mike

mike, logic says your are correct. all my tree sare going in the ground with no root restriction and i fully expect much larger crops.

Hardpan clay? Where there is a will there is a way. Buy some large landscaping bricks or boulders, heck you could even use wood(you'll have to occasionally replace) and do a raised bed, fill it with nice top soil that drains. 4'x4' or larger, and make it a foot or 2 deep.

In mediterranean, as a lot of people wrote about it, you notice figs grow in rocky areas. The reason that the fig do better in rocky areas than open sandy or clay areas is not because the figs love ROCKS, but, it is because the rocks /boulders/bricks or cement... they hold moisture underneath them and fig roots take advantage of that.
Simple:)

pete, that raised bed idea of calvins will work for sure.

i bet alan's idea would work too.

with all your trees, you deserve a few inground.

Solution to all your soil problems: dynamite.

Or perhaps just a mess maker.

Should be fun either way.

oh, a powered post hole digger could make enow  holes close together to make it easy, tho not as fun as dynamite.

aaron n alan, i'm in the desert. does that mean i sould use slabs of rock for mulch, instead of wood chips?

i can get flat sandstone but it's heavy.

Hi Bullet08 and Susiegz,
You got me laughing - 15 minutes .
Let me tell you a story of a man. He sees a fig tree for "cheap" and that should be productive as per the seller - but no name of the strain - who dares to keep that information ? After all that tag does not feed a man (Idiot!)...
So the buyer gives the tree a try. Gets back to the garden and digs an hole for an 80L trashcan (who? me! of course.).
Well after 40 cm of depth I got tired of hammering the dirt - the dirt was coming out in pellet mode layer by layer - and so I thought : Ok lets put a watering can inside the hole and tomorrow you'll finish it as the dirt will soften and the water will vanish...
Well, who's the fool that had to remove his water the next day - 24 hours later ...?!? That is what I call a clay ground - in that case a clay pot . All my water was there the next day staring at me !
I couldn't believe it. Would someone have told that story to me, I would have called him : liar !
To finish about the digging, I removed the water and 10 cm more of dirt, and planted the tree in compost inside the 80Liters trashcan ( bottom cut out ).
So far the tree leafed out - but no brebas on her for now ! My 2 cents are on a BT strain or a brunswick perhaps Longue d'aout - time will tell or I'll never know for sure.

jds, i'll stop complaining about my soil, even tho it's sterile. worms can't live here.

alan, i can't make a wall of stone, but i can circle each tree  with dinner plate sized stones.