Very difficult; I would look at open source projects somehow related to what you need. There are developers that are 10-times as productive as others, or 100-times. These you need to get motivated; Sharing part of your company is tough if they do not hang around for the long term, so if you give them options, have it mature over a few years.

Go for cheap, newbies hardly ever pays off. Imho domain knowledge matters, too.