"Space in space" is cramped only because we put up too small living quarters. But an inflatable balloon only for growing things in it need not be especially rigid or robust. It wouldn't even have to be rigidly fixed to the living quarters, it could float a bit to the side connected only by flexible tubing.
That's not really true thanks to micrometeors. They'd have it ripped to shreds, and if it was connected to the main habitation units, would remove the air from there too.
I think I'd take inspiration from the sandstone fortifications I saw in Florida as a kid, that stopped cannonballs by basically eating them whole with a super-thick barrier of soft sandstone.
Cook up aerogel panels 1m thick, and layer them over your inflatable shell. The panels would still be translucent to sunlight, although it would scatter significantly. Micrometeorites would plow into the aerogel, making micro-tunnels in it until the kinetic energy dissipates. The micrometeorites would then remain embedded in the panels. Larger impacts could still plow through the panels completely, to breach the inflatable envelope, but those are more easily tracked and avoided. Panels that get too shredded can be replaced, and the micrometeorites harvested from them for study.
