Further details: the pebble tray is a recent addition; the Deliciosa was in a plastic drainage bowl before, which had little grooves at the bottom that held water. Probable cause of the yellowing I saw when I got back, if that wasn't just the heat and dryness of the room.

There was/is a small gnat infestation when I came back, so I waged war with Hydrogen Peroxide (3%, 1 to 4 with water mix), food-grade diatomaceous earth (the white stuff in Obliqua's pot), and sticky traps. All of that stuff appears to be eradicating the bugs.

About Deliciosa's drainage: this is the biggest pot I've ever had (I'm used to ~6-8 inch; this one is 11.5. It's this pot.) so I can't tell if it's draining well. I had to drill the hole myself; it's just over 1 cm. A whole bunch of water comes out and I use a turkey baster to get it out of the drainage saucer (now pebble tray; new saucer) but it takes a few minutes to get through the soil. The water keeps draining out over ~10-15 mins. When I water it (I stick a finger in to check when, but just ordered a moisture meter instead) I use the hydrogen peroxide / water mix to (hopefully) aerate the roots.

I also have fed both plants once since getting them, with Superthrive. Just ordered Humboldts Secret Golden Tree to try, as well.

P.S. I've been lurking here prior to joining so most of that stuff is advice I've recently learned from browsing the forums and elsewhere. Still, I haven't seen other photos of leaf tears like my Deliciosa's, nor such intense brown and yellowing.

I'm going to guess this plant suffered from both a lack of moisture and the radiator being too close. With good care it will most likely revive, even thrive.

@Mentha, thanks for offering! I've collected too many perforated Monsteras; found two more big ones locally. (I don't know if they're obliqua, friedrichsthalii, or adansonii. I read they're supposed to be synonymous but the leaves are different; one has much pointier leaves than the others, with smaller slits).

But if you need to send them away, sell them on eBay? I'd be happy to adopt another, too!

That little one is doing OK right now. (Making a new leaf, looks clean.)

I've learned a lesson: DON'T go crazy stripping "root bound" plants, and pot up according to root size, not plant size. (I don't know how plants survive suggestions like Figure 2. here; a nursery owner told me they actually don't touch the outer roots at all when repotting, and just add more soil around them. Their plants look great.)

I thought I was "helping" them by trying to put them in coarser soils like suggested here, but they didn't enjoy the excessive root pruning when I tried to remove the old soil. And I used way too much hydrogen peroxide in trying to compensate for their new, over-large pots. (Something like 1-to-4 rather than 1-to-11 of 3%; surely burned them.)

Anyway, I've repotted again (downsized) and am letting them rest and recover.

P.S. nice Skyrim icon :D

Thank you. I got that cup and a Dovahkiin action figure for my husband for Valentines Day. This is how he looked when I came home last night. I'm impatiently waiting for our new computers to come in so we can play Fallout 4.

Adding soil only works if you use the same soil as is in the pot to begin with, otherwise it can cause a lot of wicking problems, the root ball not growing into the new soil, rot when it does, peat soil not getting saturated and turning into a brick but the rest of the soil is wet.

Like Mentha said above, you can't have two different types of soil. You should definitely wash away all the old soil that was entangled in the roots. I actually see nothing wrong with the illustration in your link. Roots are not always as delicate as we imagine them to be. As far as root trimming, I was afraid of doing it at first, but now I love it.

Thanks Mentha and Hellkitchenguy! Understandable. It makes sense that the nursery owner told me they don't touch the roots, too — they're going to be using the same soil, vs. someone who purchased the plant and might use a different one.

I was/am skeptical of the root trimming because, I think I just haven't done it correctly, or perhaps was too vigorous about it. The couple of plants I decided to root-prune haven't done well at all (the Deliciosa is still suffering, months later — I've tried to correct its conditions but it keeps yellowing and browning, I don't know if it's salvageable or not).

The other is a Philodendron selloum that was extremely root-bound upon receipt, a couple of months ago. There were also insects in the little soil that was left, so I pruned it and gave it some H2O2 treatment (perhaps too much, I've now realized). I've attached a photo pre-pruning; the white stuff on top is DE. It's finally recovering and new growth looks alright.

Is it normal for them to go through such a long period of distress before coming back up again after pruning?

I don't tend to root trim unless the roots are broken or rotting. I've lost too many orchids by trimming roots that I just don't do it anymore. I just take my plant outside and grab right next to the root ball then bang it on the ground, or a wall, or my porch steps a few times. This usually loosens the soil. You can then tease the roots apart with your fingers. If root trimming is needed, now is when I'd do it. I use cinnamon on the cuts then plop it in the new pot with new soil. I don't water for about a week afterwards to give the roots enough time to heal. I then trim off a few leaves to compensate for the loss of roots.

I find the easiest way to remove soil from around the roots is to dunk them in a bucket of water. Usually the soil washes away fairly easily and with less damage to the roots.

@Mentha I am interested in a monstera cutting if they are still available! I can pay for the postage too!

I'd love a Monsters cutting myself. They're hard to find where I live.

I just got one from local grocery store, and it has the same problem. I am so worried. Would love to have a healthy Monstera cutting. I will pay the postage.