I have about 50 potted Fig trees on the ground, most are one to three years old. In spite of rain almost every day since Spring and cold temps. they have thrived and most are loaded with main crop figs. The past 5 days have been sunny and hot with temps. in the high 80's and low 90's. On seven plants starting at soil level the leaves are turning bright yellow. It does not appear to be sunburn as the upper leaves are still bright green.
There is no sign of rust or discoloration other than turning from green to bright yellow and of course these will eventually dry and fall off. I can see one or two leaves on other plants starting to do the same thing. They have neither too much nor to little water.

Does anyone know what causes this? I suspect they are lacking in some nutrient but I don't know what.

If anyone has any suggestions please let me know. If these figs ripen before frost it will be my biggest crop ever.

Peg

Often, older leaves yellowing indicates a small nitrogen deficiency. Nitrogen is a mobile nutrient and if the plant is vigorously growing now that the temps are warming up, if there is a small lack of food ( this often happens to plants in pots) the nitrogen from the older leaves will be mobilized and moved to where it is needed in the new growing tip. Try feeding with liquid fish or with compost.

If you want to improve your outcome.remove the first 2 leaves,of every branch,once the branche grows,up,and have more than 6 leaves.
Even before those leaves are getting yellow.
This is an old trick from old timer,and can't explain in details,but noticed it works.
H2

I'm wondering if its stress from the hot days/cooler nights. 60-90 degrees is a heluva swing...

Thanks for the suggestions.

Jackster, I thought about the heat stress but I have 12 young plants started in Jan. on the deck where it is much warmer in full sun and they don't seem to be affected. These youngens have gotten more MG fertilizer than the ones in the yard so maybe that is the problem. Maybe they need some more food.

Peg

If I remember correctly from the old posts by experts saying that leaves yellowing at the top of the branch indicates lack of enough moisture, while leaves yellowing at the bottom means more moisture (water) at the roots; could the soil in these few pots be more moisture retentive or receiving more water than others?

A big increase in temps more than likely was not matched with a timely increase in water, both in quantity and frequency. In general, yellow leaves are a sign of not enough water, not enough fertilizer, or too much shade (often bushier growth at the tips shades out the lower leaves). In general, the plant has determoimed that it has insufficient resources to maintain all of its leaves, or it has leaves that are not contributing (lack of sun). If you are also getting small brown spots on the other leaves, also, water is definitely insufficient. That is a sign of stress. You are not likely to damage any of the plants by increasing water, even if they have been too wet. You will defintiely damgae them if they are underwatered and you cut back.

Thank you all for the advise and suggestions. Today I gave them a good drink of fertilizer. I hope it will stop the progression. On some of the bright yellow leaves there still is a hint of the green fading. No black or brown spots. They are actually quite pretty but not what one wants to see. It has been a tough year here weather wise. It seems like the figs have been on the trees just too, too long and still have a way to go before they ripen. Last year at this time I was eating figs. Thanks again folks.

Peg