r3tic

I measure a banana from the point where the new leaf comes out, basically the trunk height. For soil you want to go with an organic, quick draining one. If the soil in your yard is not quick draining then you will want to consider a raised bed. In clay soils if you dig a hole and then plant in it, you basically make a pool of water and end up with a rotting banana. To help prevent wind damage, start strengthening you plants now by using an oscillating fan on them. That will encourage the plants to grow stronger. I'll leave the staking question to someone else as I have never done it with bananas before.