Well, the light shouldn't be a problem unless it was in dim light before you brought it home (hiding in the back behind other plants?) and couldn't take the shock. Also, how dry is it in your house - if it's anything like the usual for your area, it's probably pretty low, so you want to get a big wide tray or something full of rocks under the pot, full of water, but NOT high enough to touch the pot or roots will rot - but it's a lot better than spraying 1-2 a day. Many plants will drop leaves in new locations (ficus is terrible that way), but don't overcompensate and overwater, because leafless trees can't use much water at all, so let a good 20% of the soil dry before you do it again. You might want to back it away from the window just 1-2' (again, don't overdo it) for a week, just to let it acclimatize a bit slower to the light. And give it a few weeks to recover and start growing new leaves. Relax, it's not dead (or shouldn't be) and it just needs some time.

We don't get much rust here in NJ, unless it come in imported on a plant via mail order. Rust looks like the orange dust from Cheetoes/Jax corn curls. We are more likely to have blackspot or powdery mildew. Your plants have blackspot. Age of plant doesn't matter, some varieties are less resistant to disease. By "Bayer rose fertilizer" do you mean one of the Bayer Advanced combination products (fertilizer/insecticide/fungicide)? These are not effective for blackspot control. The fertilizer isn't enough, the insecticide kills worms, and the fungicide can't be effective in time to prevent an outbreak of blackspot. For effective blackspot control, try Bayer Advanced Disease Control for Roses, Flowers, and Shrubs. It is a fungicide only. This can be started now, applied once a week until the disease is under control, then every 10 - 14 days. You can use a small spray bottle, and measure the product accordingly. Next year, start your fungicide treatment about a week after pruning in late March/early April. Make sure that the plants have been watered well before applying the fungicide. For fertilizing, try Espoma Rose-tone or Espoma Holly-tone. These are organic, and they also provide amendments to the soil. I also apply a layer of composted manure in the fall. Also, check the amount of water that the plant is receiving. Roses like to be watered deeply, and less frequently. The top of the soil may look moist enough, but the roots may not be getting enough moisture (even with the rain we've had this spring).

they do go dormant with lower temps and lower light and drop some leaves (sometimes all). But they won't if you keep them even in winter at least at 70F. 75F would be better still. they grow best in heat at 80-85-90F and lots of water and humidity..which you can only get outside in summer, unless you are subtropical.. I wake up mine by putting them on heat mat, keeping them moist and ultra humid in plastic for at least a month. Until they start sprouting the 1 st leaf. without the heat at the roots they won't wake up. keep them dry until you can do that. if you water them at 65F and below the tubers will just rot. the tubers can go dry in the pot for sev months depending on size (the larger ones can last 3 mo, the small ones better to wake them up earlier).

Hi Jarod, See the link at the bottom. It is a VPD vapor deficit chart. You can also find it in my idea book. In the chart find the intersection of temperature and humidity. The new growth is falling off because the VPD around the new shoots is either in the dangerous level, high stress or flower area. You need to keep the VPD in vegetative or nursery VPD to have the new growth survive. The higher the VPD the more moisture gets pulled from the plant. At 71-73F and 50% you are have a VPD of between 1.32 and 1.45 which is way to high for new growth. It is actually much worse than that because you have to use the surface temperature of the leaf which is going to be much higher than the air temperature. Without a breeze indoors leaf temperature in a sunny window would be closer to 80-120F. When you put those temperatures in the VPD you will see you are way off. In my idea-book there is a battery operated mister which I use which is really helpful. You need to mist the new growth as frequently as possible. Outdoors wind is going to cool the leaves. Indoors air doesn't cool the leaves so you need to add some mechanical fans. That is complicated to do as too much air will also dry the leaves out if the humidity is low. I grow in clay pots and love them. Very hard to overwater in a clay pot if you are using a good potting soil. The downside of clay pots are the weight when you have to move them around. Fixing the potting soil WILL NOT fix the VPD. Waiting to water when the meter reads 2 in my opinion is too little too late. Your mature leaves look pretty healthy. You really need to lower the temperature below 70 to work with 50% humidity. Indoors fall and spring are the easiest time to grow citrus indoors. Winter and summer are the hardest because of the low humidity in the winter and the high heat in the summer. Also you have to keep an eye on the radiant heat from the light. You need to measure leaf temperature with an infrared thermometer to get accurate information on what is going on. When you buy potting soil look for the maximum humidity on the package. Also referred to as maximum water content. If you over water the plant it will self balance to the maximum humidity. You want to keep citrus roots in the 40-60% moisture level. VPD-Bioengineering-Chart-1.jpg (5032×3388) (ceresgs.com)