Looks thirsty to me, what kind of potting mix are they in? That one in question is also a different color.... regardless getting 3 out of 4 seedlings to survive isn't that bad.

The soil is a mix of perlite and miracle-gro Citrus. Thirsty is odd since it gets watered the same as the others, and registers still some moisture today (watered on Sunday). Any other idea?

You say that you measured 2-3 inches deep? Is that the depth of the pot or is it deeper than that. Does soil still cling to the probe or does it come out clean? Things like sand and gravel can throw off readings for moisture probes so you kind of have to recalibrate (read figure out what is wet/dry) for each mix. If soil is still clinging to the probe, then the soil could be overmoist. If not then your tree may be underwatered. I would hesitate to say it is underwatering during this time of year if you're watering once a week and misting the soil.

A small tree in such a large container is a common condition for problems or death of citrus trees.

It looks like it could be the growing temperatures are not warm enough, or that the indoor air is too dry. Turning up your heater setting will NOT help because that will just make the air more dry.

When you water, try watering directly into the base of the plant. Small newly planted plants still have very small root systems which can have trouble supplying the plant with enough water. In very large containers, most of the water is likely to drip down below the root system. You will need small amounts of water and to water more frequently.

Some people might suggest putting a clear plastic bag over each of the plants to help hold in the humidity and reduce water stress. If light is an issue, a directional LED bulb aimed at each plant may help.

Yes the probe comes out almost dry, some dirt clings a bit to the probe but not much at all, and the pot is 6 inches high total. I register about 4-5% moisture 2-3 inches deep on all plants.

What is the recommendation for the pot size based on your experience? Those ones are about 6 inches diameter... the plants are about 5-8 inches in height (from top soil). Thanks for your feedback.

Have you tried feeling the soil moisture with a finger? If the probe comes out clean that sounds to me as though the soil IS dry. Something you might do is to place the pot in an oversized drip tray, fill the tray and let the soil absorb from below. (I don't use this for larger plants, but I've had some success doing this with seedlings.) The water temporarily raises the humidity around the plant and helps the roots not to dry out. Water again when the soil feels dry. A 6 inch pot shouldn't stay too wet, but it all depends on the plant and how established its root system is.

I sprayed some rot fungus control product this week too, just in case.

==>>>

never spray anything unless you actually have a problem to fix ...to spray for anything that isnt there is technically pollution ....

i might be out of the loop... but i never heard of foliar application of a rot preventor ... unless you mean a fungicide ... if you sprayed them in sun.. you may have burned or injured the leaves ..

most plants can releaf.. if you solve the base issue ...

you also said: The Moisture sensor registers about 4-5% humidity at 2-3 inches deep

what gizmo measures ambient air humidity at depth ... i think i know what you mean.. but you didnt say that ..

insert finger into the soil.. and learn how to gauge moisture in your media ... so you can throw away the meter gizmo ... they are famously inaccurate ...

tree are not easy houseplants ... you should be doing the happy dance that you got 2 this far.. and not unhappy about losing 1 ...

id probably take a tablespoon.. and dig a hole as deep as you can.. AND FIND OUT IF THERE IS ANY MOISTURE IN ANY OF THE MEDIA AT ANY DEPTH .... and when you find out its bone dry.. thru and thru.. throw out the gizmo meter ...

and if you dig in one of the other pots.. you will probably find there is more usable moisture ...

generally.. trees like a drink of water... total drainage of excess ... but that doesnt mean they want to be very dry ... again.. i dont know what 4 to 5 % means.. but that is very dry .. except for maybe a cactus ... but then.. i dont know what gizmo you are using ...

ken

Hi so I followed 3 advices on this thread saying the trees were most likely thirsty. I touched the dirt 2-3 inches deep, and it was not fully bone dry, but not wet neither... in any case, i checked the other ones, and had the same soil situation, so i went ahead and watered the trees.... that will then be 2 waterings this week, one on Sunday, and one now. Hope it works out and not too much, but you guys are more experts than me for sure.