Notice how only half of the leaf is turning brown ..... and it's the half that isn't shaded by the leaf above it? The underlying cause of that particular leaf's issue is photo-oxidation - commonly called sunburn. You'll notice too that the affected leaf is an older one. There is already a new branch growing in the axil (crotch) of the old leaf. Actually, I always remove these older leaves with active buds or branches in their axils. The reason is, it slows extension of the branch, which means the internode length (distance between the leaves) will be shorter, making the tree fuller and more compact.

A Ficus cutting which has 2 old leaves, each with a new branch forming in the axil of each. Normally, I remove the mature leaf about the time the first leaf on the new branch starts to open, for reasons mentioned.

Also, not all leaves are adaptable to significant changes in light levels, as in from indoors to outdoors. Something I wrote about a leaf's ability to adapt to light changes:

Light Acclimatization

The degree to which a leaf can 'acclimate' to changes in photo load is limited. IOW, you can't expect a leaf that emerged under a full sun light load to acclimate to light levels in a dim corner, any more than you can expect a leaf that emerged in a dim corner to acclimate to a full sun site; this, no matter how long you allow for gradual acclimation. Too, the plant's ability to adapt to higher light loads is greater than its ability to adapt to lesser light loads.

Using a 1-10 numerical example to illustrate (numerical value of 1 is low light, 10 is high light): If a leaf emerges where the light level is measured at 5 units, it's range of adjustment might only be 3.5 on the low side, but 8 to 8.5 on the high side. When the level of adjustment required is greater than what the plant is genetically programmed to deal with, the leaf is shed. Whenever a new leaf appears it will be perfectly acclimated to whatever the photo load is where the plant is positioned (within the limits of what it is genetically programmed to tolerate).

And here's a link to a thread that discusses Long Term Care of Ficus Trees in Containers. You should find it very helpful ..... at least I hope you do.

Monitoring soil moisture levels deep in the pot (as in 'at the bottom) is far more important than how dry the soil is at the top. I don't want to overwhelm you with information, so let me know if you'd like to read a short piece about how to use a 'tell' to 'tell' you when to water. I promise it will make a difference. I mention it because the first image looks like it serves as witness to over-watering.

Al

always what al said ...

where are you.. biog city name ...

how long has it been outside ... or does it not come indoors for winter??

did you harden it off before you put it in sun outdoors...

can we see the whole plant and pot.. is the pot the right size for the plant.. when is the last time you changed media ..

other than the weird marks.. you havent told us much of anything about the plant ...

over or under watering can be an indication that the water management system.. otherwise known as the media.. or medium.. is failing.. why is it failing??? i dont know.. all i know is you have leaves with brown marks....

ken

This is all very interesting. I have seen sunburn on plants before but not on ficus. So it didn't look familiar. These live under lights in the winter and outside in the summer. (Zone 7a) They are put though a hardening off period--mainly for temperature, I thought. And their new outside home varies between dappled and bright light.

I know the whole group has been overwatered recently due to heavy rains one afternoon after another. I'm not sure what to do about this. I think the fastest draining soil would stay wet under these conditions.

Thanks for the advice about mature leaves and the article about ficus trees. And yes, I would be interested in reading the article about using a 'tell' for watering.

First, here's something that explains that a leaf's ability to adapt to changing light loads is not absolute. No matter how long or gradual the adjustment period is, some leaves simply might not have the ability to adapt:

I think I already posted this, but here it is again:

Light Acclimatization

The degree to which a leaf can 'acclimate' to changes in photo load is limited. IOW, you can't expect a leaf that emerged under a full sun light load to acclimate to light levels in a dim corner, any more than you can expect a leaf that emerged in a dim corner to acclimate to a full sun site; this, no matter how long you allow for gradual acclimation. Too, the plant's ability to adapt to higher light loads is greater than its ability to adapt to lesser light loads.

Using a 1-10 numerical example to illustrate (numerical value of 1 is low light, 10 is high light): If a leaf emerges where the light level is measured at 5 units, it's range of adjustment might only be 3.5 on the low side, but 8 to 8.5 on the high side. When the level of adjustment required is greater than what the plant is genetically programmed to deal with, the leaf is shed. Whenever a new leaf appears it will be perfectly acclimated to whatever the photo load is where the plant is positioned (within the limits of what it is genetically programmed to tolerate).

Using a 'tell'

Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant.

Watering in small sips leads to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor.

In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water.

Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'.

One of the most reliable methods of checking a planting's need for water is using a 'tell'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16” (75-85mm) would work better. They usually come 48” (120cm) long and can usually be cut in half and serve as a pair. Sharpen all 4 ends in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell comes out dry or nearly so. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue.

Al