Hu, do you even know how water your tree?

How long has the mix stayed moist or wet?

Have you ever let it dry out to the point the leaves wilted?

Can you take a few pictures for us, of the mix up close, and the tree itself.

Denise gave great advice.

Mike

Thank you both for your help! I took it to a local nursery and they confirmed it was due to overwatering. Should I let it dry out completely, or should I mist it a bit? The visible roots are a light brown, not dead but not healthy, either. I haven't watered it for a few days and it's losing less leaves!

picture or conjecture?

In nature, there is a symbiotic relationship between ground temperature and air temperature which regulates root temperature, leaf temperature, transpiration, and photosynthesis, and metabolism in harmony. When you bring citrus indoors this relationship is very difficult to maintain. Leaves are often shed when there is a major temperature difference between the roots and leaves. Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. The transpiration rate is a function of ambient temperature, root temperature, leaf temperature, humidity and light. As a reference point, a greenhouse overwintering citrus would have a temperature of say 77F and RH between 60-70. Your home is 75-85F and guessing your RH is 30-50 (depends where you live). If the air in your home is dry it would put the VPD in a danger zone (Google VPD calculator). When you have a high temperature and low humidity it creates a high transpiration rate where the plant is exhausting moisture too fast. The higher the VPD the faster the leaves will dry out, drop, and turn brown. The citrus will drop leaves until enough leaves have dropped that it can maintain proper transpiration function. What you can do is lower your temperature, increase your humidity, use a humidity tray at the base of the citrus, and use a very small fan. Air flow will help the plant leaves cool and conserve moisture. Too much air will do the opposite. Leaf temperature in the window would be 95F or higher. You can buy a non contact infrared thermometer on Amazon for $25. Other issues are the leaf temperature from the sun, the root temperature, and the amount or lack thereof of photosynthesis. The transpiration rate is a function of three in-house variables: temperature, humidity and light. Also indoors in dry conditions spider mites will suck the moisture from the plant compounding the other problems. Either reduce the temperature or increase the humidity. More or less water will not fix problem. You really need an RH between 60-70 to maintain that temperature. Think of Florida where the average daily high and low RH is roughly between 60-90RH on an annual basis. Nature provides high humidity to protect the leaves from the intense heat.

Top Ten Tips for Citrus Care

I really like this video as it has some great ideas. Notice she looks at the soil, looks at the leaf and looks at the roots if necessary to determine when to water. Keep in mind that she is growing under "perfect" greenhouse conditions with very high humidity. It is easier to control watering in a greenhouse with high RH than it is to control humidity in a house with dry air. What you are saying is typical for growing indoors where you have not watered in a few days and it is getting worse. More or less water will not solve a stress condition from high VPD problem.

The Truth About Indoor Citrus

You should consider sticking one of those wooden BBQ skewers into the soil to help you gauge the moisture in your soil. Again, only water when the top 1-2' is dry. The top part is where the feeder roots are and they do most of the work for the tree. If your tree is in the original mix from the nursery, it probably has a peat based mixture in it and it stays wet for a very long time. Keep it in a sunny window and let nature take it's course. It may take a week or more for the tree to recover so have some patience.

No pictures.........so its conjecture

You want soil with even moisture that is moist but never soggy or waterlogged. Watering frequency will vary with soil porosity, tree size, pot size, and environmental factors. If you want to take the guess work out use a Sustee Aquameter available on Amazon.

SUSTEE AQUAMETER – SOIL MOISTURE METER

I looked at the aquameter and didn't like the idea of purchasing refillable cores. I will stick with the finger testing as it's free and I feel nothing beats the sensitivity of the fingers.

I will stick with over watering to insure total saturation, then suck the excess water out while aerating the roots.

New Zealand lemonade on US897 rootstock. · More Info

New Zealand lemonade on US897 rootstock. · More Info

Steve

When you grow indoors, once you find a sweet spot in a watering schedule like every 7 days or 10 days and the plants are happy, things don't change much......I write it down in a small notepad and if your off a day or two no biggie, I also use the wood skewer method although I don't bother much and stick to a working schedule. I would recommend a spot light aimed at the top of the roots/rootstock hooked up to a timer, to go on one hour before light comes in the window, so roots are capable of working and feeder roots are kept warm.....

Your soil is colder than the air temperature......if you posted a pic you might get more accurate assessments

Bklyn: For tropical plants the soil temperature is always lower than the air temp in summer during daytime. That is the norm. During night it may reverse under some conditions. May be you wanted to say something else. If you want growth then soil and air temp both should be raised and so should humidity.

Soil Temperature and Citrus. Low soil temperature contributes to low number of roots under citrus in some areas of Southern California.

not necessarily air temperature, just soil. Why make leaves transpire more than necessary. when I take temp readings here in fall indoors, air and soil are close (yes soil is coler by a couple but not much and vary) and high air temps with TOO cold soil promote leaf loss. I grow in a basement thats heated with steam, humidity for me is a non factor and non consideration. If he has forced hot air in a different location etc. etc.