Question: Total newbie here as far as home improvement goes, I'd love some advice from the community!

I'm considering building a little office-shed (for remote work) in my backyard. From what I can tell, in order for electric run to the shed to be up to code, it needs to be buried underground.

There are two problems in my case:

1. There's a slab for a concrete patio right below my electric panel. I don't think I could add a conduit without jackhammering the concrete.
2. The place I want to put the shed is on another (lower) "tier" of the yard. I can't run a conduit from the panel to the shed without digging a *super* deep trench.

Here's a outline of the property: <https://cl.ly/fdd96711937f>. What I'm wondering is if I can piggyback the shed electric off of the garage. There's a subpanel in the garage with a conduit already buried through the concrete patio pad. The shed would be placed behind the garage so I'm thinking I could run another conduit off of the back of the garage.

Is this possible? Or does the conduit need to be run off of the main panel to be up to code?

Any other ideas on how to get electric to the shed?

Thanks!

Answer: 
There is no problem with running the feeder from the garage's subpanel to the shed.

The only thing you have to watch out for is the remaining capacity of the garage's panel.

The heaviest load in the shed is going to be climate control if you choose to install one. All the rest you'd need for remote work can be powered of a single 15A circuit.
You can set up the shed as a subpanel of the garage subpanel, supplying it from a 2-pole breaker in the garage. 

Alternately, if the sizes make sense, you can avoid using 2 breaker spaces and simply continue the garage feeder onto the shed with the same size wire. You would either double-lug the garage main breaker, or use a wire nut or 3-lug terminal block to split it. 

Either way, the circuit to the garage must be sufficient for both garage and shed loads.