Pothos is supposed to be incredibly hard to kill – damn near impossible, in fact. That’s the reason it’s called the ‘devil’s ivy’ plant. However, some of us (myself included) are talented. Give us a plant that can’t be killed, and we’ll feed it and cater to it (or vice-versa) until it gives up on life.
Yeah, I’ve killed a few pothos plants. If yours is dying, don’t worry. We can (probably) troubleshoot this.
First, check the plant’s leaves carefully, and insert your finger an inch into the soil. Do you see any signs of pests or diseases? Is the soil wet an inch down, or dry?
If you see pests or diseases – identify what they are, and treat accordingly. Be warned, if the plant’s suffering from rot or spidermites, you’re probably not going to be able to save it. If it has spidermites, quarantine it NOW. Those are some determined buggers, and they take over quickly.
Now, let’s talk about the soil. Is it wet or dry? Unless it’s ‘nearly dry’ – which is how pothos likes it – how long has it been that way? Has the plant been left outside during the rainy season? Or did you forget to water it for 3 months?
If it’s dry and the plant’s not completely dead (i.e., you can still see green bits), it can probably be saved. Give the soil a good soaking, and make sure the water can drain away. Then wait.
If it’s wet, you have a bigger problem on your hands. Pothos really doesn’t like to be wet. Elevate the pot to facilitate better drainage, and poke a few deep holes in the soil to aerate it a bit. If the pot’s big enough, place it in the sun while keeping the plant itself in the shade. Try repotting it into a bigger pot, and fill in the gap with dry soil. You can even spread an inch-thick layer of dry sand on the soil surface. It’ll get wet in a little while. Scrape it off and throw on some more dry sand. And do not water it again unless the top inch of soil is bone-dry.
If the plant’s leaves are really grimy or dusty – whether it’s a standalone problem, or in addition to others – give it a wipe. Moisten a rag, and wipe the leaves down one by one. If there are too many, hose the leaves down. Put your thumb on the hose end and press, to create a little water pressure.
Nutrient deficiency is another factor to check while troubleshooting plants, but pothos does well in poor soil, so that’s unlikely to be the problem here. However, if none of the other suggestions work, give it a try – especially if your soil is excessively poor, or you know it has too little (or too much) of certain essential nutrients.
After troubleshooting, if the plant’s health continues to decline, make a last-ditch effort and take some cuttings. Get 2-3 nodes on each, and try to get cuttings that have some air roots on them. Plant them in and hope for the best.