I grow a ton of Calatheas and Marantas but mine have an advantage of being planted in the ground. They just do not make good long term houseplants. There are probably several factors affecting your plant, and when they affect it "all at once", it can lead to big problems. #1--most Calathea are not high light plants. This is a good rule of thumb to follow for light: if a plant has leaves that have red or maroon undersides, its a shade or low light plant. The red coloration is a genetic adaptation of rainforest plants that thrive in moderate to deep shade. The pigment is made up of specialized cells adapted to catching what is called "green light"...this is light that filters through the canopy layer, hits the ground and bounces back up. These plants with red undersides are specifically adapted to catching and utilizing green light. So putting your plant right in an unobstructed South facing window might have been a little too much light all at once. #2--almost all the Maranta and most of the Calathea have a sensitivity to not only chlorine but also mainly to fluoride in the water. Since most municipal water supplies are both chlorinated and have added fluoride for the kids teeth, you shouldn't use it for plants like these. Your water may also contain added ammonia, which forms what are called "chloramines" which are also bad for plants. All this will cause leaf troubles like the crispy edge. Using pure spring water, distilled or purified water is a good start. #3--Humidity is a key factor for these plants and misting and a pebble tray may still be inadequate, especially in a home in a Northern zone when it gets to be winter and you turn the heat on. Air conditioning is bad enough in summer, drying out the air but the heater is killer in winter. If you can stand it, you might have better results if you purchased a cheepo cool mist vaporizer from Walmart and ran it on a timer to cycle on and off in the close proximity of any plants you have that require higher humidity. You could group all your needy plants together maybe and hit them all at once. #4--5 fertilizer sticks is just way too much for a houseplant that is already stressed.And Calathea and Maranta can be resentful of too much fertilizer. Since you have trouble keeping your plant adequately watered in the first place, it would be much better to err on the side of underfertilizing and just use some 1/4 to 1/2 strength water soluble maybe once a month. #5--if you had white bugs AND webs, you probably had a mixed infestation of mealies and mites. The webs are from the mites, mealies don't build webs. But mealies do infest the soil and also lay eggs in the soil. Calathea and Maranta are rhizomatous plants, and mealies can attack the plant below the soil level. To be certain they are gone you may need to use a systemic pesticide that goes into the soil, like Bayer, on a regular basis. Your plant sounds like it is trying valiantly to make a comeback and you sound like you did your research pretty well. Just give it time.

Are the publications you've been reading based on some kind of scientific evidence? Granted there could always be something we don't know yet about fluoridated water but everything I've learned as a public health professional is that it is one of the single most effective public health measures ever put in place with no scientific evidence of any harmful effects. As a result there is now a generation of adults who grew up with fluoridated water who have never experienced tooth decay. I would be very interested to know if there is some new scientific evidence that it's harmful.

I would probably go with what the doctor says. It may have something to do with where you live. I think certain areas have more flouride in their water than others. If it's below a certain number than supplements are recommended. You could call your water dept. What do other people in your area do with their babies? If no one else is, I would specifically ask your doctor why he thinks it's needed. Personally, I wouldn't use bottled water for a baby...too much chance of bacteria. Tap is usually better.

There is a book titled "Container Gardening for Dummies". You might be able to source a copy through your library or second hand via E-Bay. Pity I didn't have a copy when I had a 3rd floor, west facing balcony in Sydney. Even the garden gnome died of thirst! I put it all down to gravity and the scientific need for the water to reach ground level. I'm certainly no balcony gardening expert but I would recommend pot plant saucers, water holding crystals in your potting mix, and mulch. The precise recommended water "dosage" might be a bit difficult to adhere to. The requirements of the Dracaenae are going to depend on what it uses up itself and how much evaporates - and this depends on growth, daily climatic conditions, etc. Also depends on the type of pot - eg, terracotta which allows water to evaporate through the sides. I'd aim to keep the potting mix moist and, yes, check the moisture beneath the top of the mix. The Dracaenae would also probably appreciate regular spraying of their foliage - pick up a cheap spray bottle from your local dollar shop. The yucca, a desert dweller, is incredibly drought hardy and would need very little water. The problem is that once pot plants dry out, they can be extremely difficult to "wet". I'd water more often than once per month, but only use small amounts of water. If your pots do dry out completely, water them by immersing the whole pot in a larger container of water (laundry tub if your pots are large) and leave to soak for a couple of hours. Another observation - balcony plants seem to be happier in the close company of friends. Position your pots in a group.