I Just got a black mission fig tree from my local market. Its about 3 feet tall and came in a 2 quart container. Since I garden on my rooftop I bought a 24 inch pot and about 50 pounds of soil. I transplanted the tree into the new pot. After a few hours the leaves and branches started drooping. I watered when I transplanted to settle the tree. I have looked online and found no real solution. The tree's main center branch is strong and healthy. At night the branches perk up back to the way it was when I first bought the tree. Is this just stress stemming from the transplant? Another thought is the weather. It has been above 90 here in nyc for the last few days. I thought the tree needed full sun so I placed it in the fullest area of sun on my roof. 

Any ideas? any advice would be greatly appreciated.

It could be transplant shock.  Sure it has enough water?  Maybe put it in morning sun only for a while till it acclimates.  My trees do fine in dappled sun/shade.

Suzi

Get it immediately into the shade! Keep it two weeks away of direct sunlight and then gradually move it to the full sun location.

Figs do love full sun, but not immediately after transplanting - especially in very hot weather. If the pot is too large to move, rig up some sort of shade for it, at least during the hottest part of the day. Stakes with shadecloth, bedsheet, or even newspaper attached is better than nothing.

Good luck. Mission was the first fig I purchased too. :)

Gardening on a roof top is great, but it can get hot!  Heat stress on your newly transplanted tree is probably causing the wilting.  Go to Home Depot, and buy yourself a dolly, and roll your tree around the roof and find some shade for your tree. Then, gradually after a few weeks, bring that tree into brighter and brighter light, then into sun...morning sun is best.  Make sure that tree stays hydrated, and you don't cook those roots...keep that root zone cool, even in the shade, if necessary.  The leaves need the sun, not the roots.  The leaves "perk up" at night because the soil, and surrounding air cools off, and the roots recover.

Also make sure the soil is free draining, and not too water-retentive, or you'll drown your tree.

Get back to us if the tree starts to fail...and don't wait too long to ask more questions if the tree doesn't begin to thrive in a few weeks.

Good luck.

Frank

PS....I forgot...welcome to the forum.  If you want to grow figs, this is the place!

Aside from what good advice are being said above.;

Although not everyone but some people think it is o.k. to use top soil for potting. Which it is a NO NO. You mentioned you used 50lb. of soil but did not mention what kind?

Did you use a mix for pots?  

See?  Rafed is on top of it.  You can't just use potting soil or dirt.  NOW, in ground trees do just fine in plain old dirt, but potted ones are princesses!!  You need a balance of potting soil, perlite/vermiculite/ and some kind of grit, crushed granite, or cactus stuff to encourage drainage.

If it's a male tree in a pot, sorry, still a princess!

Suzi
But move the tree to the shade while it shakes off the trauma it just endured...

Check this forum for "Quick-Draining Mix" for containers.  Soils are for gardens, mixes go in containers.  Two different worlds.

You will be fine once you correct your culture...growing conditions.

Talk to us if you need help.

Frank