Wani/Mangifera caesia seedling help and general discussion

[Sharq]

The first leaves on my wani are kinda of shriveling up and dying. Is this normal? Its more "true" looking leaves are very frail and beginning to droop some as well and are forming a dark coloration towards the stem (almost purple). Since this is a pretty rare plant for me, I wanted to reach out earlier rather than later. It is a seedling that I started from seed 2 months ago now. I have it in a greenhouse right now, but it is still probably experiencing sub 50 temps, although that didn't seem to be an issue when it was really cold earlier.
Any general growing tips and experiences would also be apperciated. Thanks!
Pics of plant will be posted below.

[Sharq]

[Jaboticaba45]

 they really don’t like the cold.

I’d keep temps at 55 or above if possible.


But my friend has a few planted out in WPB and they look ok ish.

[Sharq]

Actually I think its the heat. My gauge annoyingly resets at 5pm so I never see the day time temps inside the greenhouse on work days, but I have the day off today at it was just 98 and going up. It looks worse right now then it did this morning (super wilty looking). I sprayed everything down at the temps already back down to 90, but on my work days, I'll probably need to take it out every morning.  That or throw a frost cloth over the greenhouse to keep it a bit cooler. I know it can get to 105/106 in there on hot days if its fully closed, but I have had it completely open, so wasn't sure how hot it was getting. Too hot it seems.

[Jaboticaba45]

Actually I think its the heat. My gauge annoyingly resets at 5pm so I never see the day time temps inside the greenhouse on work days, but I have the day off today at it was just 98 and going up. It looks worse right now then it did this morning (super wilty looking). I sprayed everything down at the temps already back down to 90, but on my work days, I'll probably need to take it out every morning.  That or throw a frost cloth over the greenhouse to keep it a bit cooler. I know it can get to 105/106 in there on hot days if its fully closed, but I have had it completely open, so wasn't sure how hot it was getting. Too hot it seems.

Ah ok probably the huge temp swings then.
After 40s I’ve seen burnt new growth.

[Finca La Isla]

Where Wani grows in SE Asia the temps are going to be probably from a low of 70 to a high of less than 90.  I have it growing here in CR and it looks pretty good.  I realize you have different conditions but it is important to avoid drastic temperature changes.
Peter

[Mvule101]

Not particularly helpful perhaps, but mine is doing well here in Northern Uganda at 3' north and 4000 feet above sea level. It does like water. mine are growing near a stream just above the flood level. Its now about 10 feet tall and growing steadily but certainly not fast, it might be a bit too high altitude. We also have a three or four month dry season here. Seeds sown in 2018.

[poopsiedaisy]

Lowest temps mine has been out in was 45F and didn't die. Want it to grow before experimenting more still seedling.

[Sharq]

I determined that the cause of decline and probable death of my wani is a crack in the stem about an inch from soil level. Wether that crack was cold by cold, heat or me (or the barn cat) being an indelicate ogre is unknown, but that seems to be its undoing. Everything above that point has since died. I have continued to keep it watered and protected in hopes of it resprouting from the seed or growing a new branch from the remaining stalk, but it is likely a goner.