I have 30 or more Brown Turkey fig cuttings, and some of those I recently transferred from their plastic soup pots to John Innis No 3 in pots are looking rather sad (see the image).  One is losing   its leaves.  In Wales here the frosts have recently been light, and the figs kept in shelter from bright sun and frost.  Any ideas why the leaves are turning yellow would be most welcome.

It looks like a simple lack of nitrogen fertilizer. But there could also be elements of too cold or too wet at work.

Hello, notice it is the newest leaf that is the worst. It is a nutrient deficiency, and because it is the newest leaf from what we can see it is an immobile nutrient. So the 2 most likely options are iron and sulfur... Most likely it is iron, and not caused because there is no iron, but because the ph of the potting mix/water is too high and or the plant is being watered too much. You can give it chelated iron (in Sluggo) and gypsum (for sulfur) but the problem will keep happening until you fix the root cause.

Looks to me like the smaller leaf is older but difficult to tell from this angle. The pattern of yellowing is that of nitrogen not iron.

I had a persistent problem with new leaves yellowing and getting brown spots similar to that. I thought I had solved the problem with extra "fertilizer" but it came back and the same thing did not work again. It wasn't until I realized that I had applied Sluggo Plus to the containers for pill bugs that I thought of iron (I associate iron deficiency with interveinal chlorosis like a blueberry gets as well) and checked the ph of the affected containers to find it was near 8... so I got Cal-Mag Plus (with chelated iron) from my local hydro shop and that worked very fast.

It looks like a compost heavy mix, so I think the nutrients are all there just not available to the plant because of a high ph or maybe too wet.

Get iron tone. It works great! 

Thank you so much.  I have learnt a lot, and will now try various actions in the hope that I might save some of them.  I hope those Brown Turkey fig sticks will eventually produce:

Hi,
Hard to judge the height of the pot. The pot is not full to the rim.
For me it is a dirt problem. Could be depleted or too small volume .
I usually fix that by replacing (a bit of ) the dirt and both up-potting .
In my pots, in need to run ahead of those problem for if I fail, the tree almost takes the season to recover.
I have two recovering and last year they didn't move anymore for the rest of the season. This year, they look better, and I already fertilized them twice with fertilizer and wood ashes.

Nice true BT that you have there !