AusBonsai

My ficus is the thickness of an index finger and I am going to put it into the ground under a eucalyptus and I am going to put it into the ground until its the size of all five fingers put together
So I'm wondering how long will it take

yup, good idea. Let it grow in the ground with plenty of fertiliser and don't trim the foliage. This will fatten the trunk.

Plant it in the open mate not a good idea under a Eucalyptus to many toxins in the leaf drop, it will do better elsewhere

Hi, I do not know much about Asian figs, but my native one got to about 40mm at the base in about 4 years from a toothpick-size seedling.

The spot I picked for it is very good, not too shady, not too hot either and I did let it grew freely in those 4 years.

Best regards and good luck

Eucs will also take the majority of nutrition and water and will basically starve the ficus. Eucs are top feeders (here anyway) and have feeder roots close to the surface. They do this to obtain moisture from dews or light rain that does not penetrate.

Totally agree with Shannon. Open ground is best.

Mate in the NT it should only take 2 to 3 years depending on what you want. You could just grow it in a styro box with great results, and it allows you to control the tree more, especially the roots. Best to grow free with 1 or 2 prunes during the year.

Tony