I’ve had this arrowhead plant indoors for 8-10 months. I haven’t killed it yet, but it regularly loses a leaf or two while putting out another few leaves. It’s currently at the most leaves it’s ever had, but still hasn’t started vining. During the winter, we ran a humidifier nearby and mostly kept the overall home humidity between 30% and 36%. I water it regularly, usually filling up the water bird and adding some water to the soil at the same time. I don’t remember exactly what soil mixture I used, but probably some standard potting soil with a bit of peat and perlite thrown in. I’ve been reluctant to clear out the dead leaves because of the reported irritant in the stems and leaves, but I now have a supply of nitrile gloves so I can start doing that.

While I’m happy that it’s gotten denser, I’d like to see it thrive more. I can put it outside if that would help, but it gets a good amount of indoor sun and light.