What is the opposite of the "green thumb" but for technology/electronics?

As having a green thumb is someone who is good with plants, jokingly, the brown thumb could be used for someone who is bad with plants.

Is there an equivalent pair for being good/bad with technology/electronics?

Solution 1:

Someone who is good with technology/electronics -

Computer-literate

: (of a person) having sufficient knowledge and skill to be able to use computers; familiar with the operation of computers.

(Source)

So if you aren't specifically looking for an idiom, I'd suggest -

Computer-illiterate

which, of course, would be the opposite of computer-literate.

You could also say that the person is "technologically inept".

You could also say -

Luddite

: A Luddite is someone who is incompetent when using new technology.

(Source 1)

(Source 2)

EDIT

Removed tech-savvy as it appeared to be quite informal.