I am surprised how many figs I find spoiled this year..
There were hardly any last year.
For the potted trees, is there anything we can do to help?
Maybe a particular mineral is missing, or a watering schedule, or else?

Mine have a full day of sun every day, no rain for four months ago and
I water once a day every morning from the top. By the next morning the water is gone.

The figs ripe fine but when opened, look brown and spoiled inside :(

This kinda spoils the fun a little ...

My guess would be over watering. Of course, you are in Socal, so you may need to water everyday. Soil surface isn't a good indicator of overall dryness, make sure the pots are light or the soil is dry about 2" down.

My potted figs only get water a couple times a week at most, but they are still fairly small.

Are these closed eye varieties also? Fruit flys will crawl inside open eye figs that aren't blocked with syrup and spoil them here.

Thanks, guys, for your input.
Is the Gino’s Black a closed eye variety? I believe so. The first 3 I picked up were all spoiled. 2 of my local light figs were spoiled in addition. Those grow in pots.
My St.Rita and Malta Black are almost ripe, will check them later to compare.

What is interesting, a friend of mine has an inground tree and he says the same. This year about 15% are spoiled while last year were hardly any.
We are going through a very dry period in California and these conditions may affect the ground tree in some way but why potted?

Also interesting is that I do not see any bad figs among Golden Celeste, Adriatic Grasa, Conadria, Str. Verte.
So I thought, maybe I could add some minerals to help with the spoilage of my dark figs.
The watering schedule is the same for all trees I have. 

   I'm not totally decided on the quantity of water needed for potted fig trees...last season I was watering on a 2 day schedule(sometimes every 3 days), and I was doing Ok until mid July, when half the leaves started shriveling up and falling off the trees...I thought they were goners, so I started watering every day again, and all the trees eventually came back, and by late Aug. / early Sept. I was eating ripe delicious figs....I know this goes against conventional wisdom, but I have been watering my trees every day since that frightful episode and the trees are thriving and producing figs(no splitting, no watery taste, no fig drop)...so I think this is going to be my schedule from now on.

Vince,
I water in a similar fashion. If it is sunny and in the mid 80's or above, I water every night. Low 80's and below, probably every other day, 70's and below maybe every third day. This all is subject to the absence of rain though, a long soaking rain and low temps could really stretch out the need for watering, overcast skies can effect this all as well.

Calvin...I think the watering schedule has to be fine tuned to each growers micro-climate and growing conditions...the area I live in and, even the back yard where I grow the fig trees all has to be taken into consideration...I also think it maters greatly whether the figs are "in ground" trees or grown in pots..for example, with the 1gal. trade pots for new trees, I find that I need to water every day no matter what the temperature, because the roots in the botton of those little pots will burn up very quickly because the sun and the soil in the black plastic pot absorbs the suns rays very quickly...I try to follow the general principles for watering, and fertilizing, etc., but sometimes you just have to find your own way.