I have this Meyer lemon tree in a pot. The leaves are slowly but steadily falling off, and each little lemon turns completely black and falls off before it even grows to like a centimeter or two. What could I be doing wrong? I have a soil moisture meter and I only water it when the meter reads “dry”. Could it be my grow light isn’t right or isnt strong enough?
The light looks underpowered for the plant’s needs. Take a look here at the “lighting for indoor trees” section and compare those specs to the light you’re using. I’ve seen a number of inexpensive “grow lights” that don’t produce the necessary spectrum or lumens, so be sure to take note of the manufacturer specifications if you decide to replace your lights
That looks like a really good resource, and according to it I do have a few things wrong. Seems like the light is probably under powered, although its hard to tell since I can’t find the specs on it anywhere (GE model #93101232). So looks like I’ll have to upgrade the light. I also put stones in the bottom of the pot and that link says specifically not to do that, I wonder how bad that actually is since it would be kind of a pain to get them out now
The GE site is terrible on mobile but I took a look at the bulb here. The site is also lacking documentation regarding lumens, but as this appears to be a product aimed at young or leafy green plants I’m confident it’s not enough for your tree. One other thing to note is that the light doesn’t seem to be hitting the tree evenly - you might be able to correct this when you change the bulb and fixture, but if you’re raising the position of the light you want to go higher on your lumen output. Every additional inch of distance necessitates an additional thousand lumens to achieve the same light intensity, so plan your upgrades accordingly.
Stones in the bottom can do a few things that change the dynamics in the pot. If there’s void space, the air pockets can cause the roots to self-prune and deflect laterally, which can lead to encircling roots (particularly in round pots, square ones don’t always cause circling as readily). The change in porosity between your potting mix and stone can also lead to excess water being held just above the stones. This video has nice visualizations of water movement through various substrates. That link will take you to the section on soil and large aggregates but the whole thing is neat. Personally, where the plant is already stressed, I’d err on the side of not disturbing the root mass until the tree goes dormant for the winter, and then address the aggregate at the bottom along with any necessary root maintenance.