Saturn

This leaves you on the horns of a dilemma. If your soil is remaining saturated for extended periods, flushing the soil of the salts that have accumulated could easily increase the likelihood or severity of any root issues currently limiting the plant. If you try to control your watering by offering only small sips to avoid the extended interval of saturation, all the salts from fertilizer solutions and what is dissolved in your tap water continue accumulating in the soil.

A stopgap measure would be to flush the soil thoroughly on a regular basis and monitor your watering habits carefully. More on that if you choose that course...... The best solution is to get your plant through the winter, then repot it into a soil that allows you to water to the point where you're flushing the soil with each watering. This resolves both the over-watering issue AND prevents the accumulation of soluble salts in the soil.

If you're interested in learning more, let me know and I'll guide you to some links here at GW that I'm sure will be helpful.

Al

The winter solstace is upon us....(December 21) and the sun wont be of much value until about mid February when it returns to support our plants growing.
But, if you put your plant too close to the window glass, then the increased rays can cause browning leaves.
WE tend to water in December, much like we water in July...and the plants pay for it.
Do the finger test and if you feel any kind of dampness, then let it go another couple days, then test again.

Don't let your plants, after watering, sit in the drainage water--otherwise it gets sucked up again around the roots which cant use it. It sits there and can do leaf damage.

If your plant is sitting on the floor because it needs to be there---get it up...on a table, shelf, pedestal or hang it up so it isn't hit with that warm draft from the heat ventilator.

For me, not having to water for a week or longer would cause the issues you are having with yours above.
That tells me your mix is much heavier than a plant would prefer. With that comes issues as Al describes.
The more often you are 'allowed' to water your plants in a very good porous mix, even in the winter, the better off your plants will be.

Good luck with your plant and if I were you, I would take Al up on his offer on the science of container growing:-) He has been a God send for my plants as also many here too have.

You have chosen the right place to reverse the damage being done to your prized plant.

Mike

Let's just say what you said raises some warning flags. Selecting and adhering to a predetermined interval between waterings is bound to cause problems. It's a near certainty that if you water weekly and aren't seeing any wilting between waterings, that you're watering too frequently. This causes a too large fraction of the soil to remain saturated for extended periods - especially in the winter when the plant's biological clock, cool temperatures and/or light levels work together to reduce the need for water used in photosynthesis. Soggy soil inhibits root function, causing a drought response (necrotic areas of the leaves), or worse - rots roots.

There is lots of information available if you really want to learn how to avoid the issues you're dealing with. Rather than simply tell you what you're doing right or wrong, it's probably more helpful to explain how things can be improved and how some of the effects of the factors currently limiting your success could be reduced.

Al

If one has a soil with insufficient air pockets for the roots to get air as well as moisture, damage to roots can occur. To compensate, allowing the soil to dry completely is the only way to combat that. Wilt is a sign of extreme distress/dehydration and should be avoided. Ideally, repotting this plant into something more chunky and airy when you are able would be the best.

Good to hear you don't see any white spots.

If only one or two, no need to worry.

Although Syngoniums should not be set in direct summer sun, during winter, variegated species, 'yours is slightly variegated,' need more light than non-variegated.

Watering. Once you see new growth, Syns needs regular watering..During non-growing seasons, soil should dry in-between drinks.

Would you happen to know if your Synonium is a miniature? Colors and leaf shape look similiar to a mini HD once had for sale.

Soil in clay dries much quicker than ceramic or plastic, but room temp/humidity/pot size plays a major role, too.
Do you water once a week for convenience or know for a fact soil is ready for a drink?

Anyway, your Syngonium looks fine. One to a few brown leaves this time of year is natural.. Toni

From what I see of your leaves, the roots are not as happy as they could/should be.

Saturn..Basiclly, shed..get rid of, 'unwanted' leaves.