A while ago I rescued a couple of large cast iron plants (Aspidistra) from a dumpster. The largest pot is 38cm in internal diameter, about 30cm deep. Even that pot is probably a bit small for the plant - there are stems very close to the edge almost all the way around.
I'm struggling to know how much water to use, and even how to apply it.
Typically, with my smaller pots, I water until it runs out the drainage holes, presumably getting most of the soil moist. But I'm not sure how to do that for a plant this big - I'm guessing that would be several litres of water, which feels a bit ridiculous.
Similarly, the "add water when the top inch of soil is dry" doesn't seem like a great metric for such a big plant.
How do I approach watering here?