That's a very old screenshot from one of the pre-alpha versions of the game. Collision handling was different back then, it was more accurate for objects, but was causing lots of issues when there were too many objects in close proximity.
However, objects will be reworked anyway, and it's still our intention to add a way to place items in the world (so they won't despawn after a given amount of time)
or use a farm dirt block and plant the fruit in it then remove the dirt block. watermelons remain like that. you have a small vine to deal with but it works. I guess you could use regular farm dirt to do it also. not just the blocks.