For some reason, the production capacity of my home planet is ridiculously low, though. About 2-3 arcs a turn and that's it. I wonder if there's any way to boost it?
Where we are, I don't think so. The only way to boost production there reliably is to have it connected to other planets. But since connections only appear when planets are far apart, we're at a bit of a loss. You can try expanding your merchant fleet to bring in all the resources from your colonies, that seems to be working well for me - I get an extra 3/4 thousands steel a week coming back from my colonies, which can only go up as they start to produce more. You should also note that your production is only going to drop as your home planet gets more advanced, it loses 300 people a turn after level 90, which means steel production drops.
Other than that, you can increase the production of your empire by conquering other peoples' home planets.
