Hi Harrison,
Yellowing plant leaves can be a symptom of many different things, and most often it is related to under or over watering. The second most common cause is nitrogen deficiency. If you haven’t tried fertilizing your snail vine recently, I would recommend a fertilizer that is meant for vegetative growth – or has a higher percentage of nitrogen than phosphorous and potassium. Pay attention to the three numbers listed on the fertilizer, the first number is nitrogen and should be higher than phosphorous and potassium (N – P – K).
Since you mentioned that the vine is still vigorously growing, I might guess that something else is causing the problem. It could be that your plant is in too small of a pot and it is becoming root bound. If you think this is the case, try repotting it in a larger pot so that the roots have adequate room.
Another issue could be that your plant is not receiving enough light. Snail vines require full sun so be sure to place it in a location where this requirement can be fulfilled.
Lastly, remember that it is normal for plants to yellow and drop their lower leaves as they age. I’m assuming that you are noticing a drastic amount of leaves turning yellow, but if it’s only a handful, don’t stress – that’s normal. If not, trying changing one thing at a time so that you can determine what is truly causing the problem.
Note: Snail vines like to be heavily watered and love humid environments. It sounds like you are watering as needed but, not introducing enough humidity. To increase humidity, simply take pebbles or peat moss and soak them in water to be put around in the tray.
Good luck!
.
