FWP:
For background see S. R. Faruqi's choices. This verse is NOT one of his choices; I thought it was interesting and have added it myself. For more on Ghalib's unpublished verses, see the discussion in {4,8x}.
The awkward and unidiomatic construction 'silence-garden', ;xamoshii-chaman , is probably best considered to be a 'reversed izafat'; on these see {129,6x}. As Zamin observes, the word 'garden' is quite useless, unless we give it a dubious bit of wordplay credit for the secondary or tertiary meaning of :turrah as a 'nosegay' (a small bouquet). Zamin rolls his eyes at this verse: 'Now please look-- does meaning emerge from these words, or not?!' And it's hard to disagree with his exasperation.
The most plausible reading that I can figure out is that the speaker's eyelids are lowered (in shame? in shyness? in absorption?), so that his eyelashes point downward and perhaps flutter a bit. Thus they are as close to the mouth as possible, and are positioned to act as a comb, and comb out the 'forelock of Speech' (which would be located at or near the top of Speech's head-- if we assume that speech has a head) in preparation for the big moment when Speech gives its oral performance. What a vividly bizarre imagination the young Ghalib had! Sometimes he could pull things off, and sometimes he couldn't; but even the odd bits left lying around can be fascinating in their own way.
Compare the more enjoyable {23,1}, in which the 'comb' of the deer's eyelashes is turned into a backscratcher.
Zamin:
Silence became a barrier in the longing of/for sight, which made it into a garden, and the eyelashes began to comb the forelock of speech. Now please look-- does meaning emerge from these words, or not?! But it should be remembered that when a poet composes a verse, in his mind there is certainly one or another theme. In Ghalib's mind too there was a theme that he versified; now we should look at what that theme was.
The rule is that when the longing for sight reaches the limit, then a person is overtaken by a kind of absentness, self-forgetfulness, and silence. One can usually notice that in situations when this mood overtakes the poet he has become a 'silence-garden of longing'. Now the second thing is that the longing is for 'sight'; thus in the silence the eyes definitely remain open. The eyelids never close. Even if someone asks for something, then [the lover] looks at him and becomes silent-- rather, for a long time he stares at him in silence. It's as if he wants to say something, but it can't be said; the tongue does not help him to speak. Instead of saying something, he lowers his eyelids. Just this is their becoming for the tongue a 'comb-wielder of the forelock of speech'.
In short, the verse is not so meaningless that nothing at all can be drawn out from it-- though indeed, it's certainly convoluted. The word 'garden' is unnecessary, but in Mirza's mind along with :turrah there would have come sunbul [=hyacinth, to which the beloved's curls are often compared], and along with sunbul there would have come chaman . The affinity was not able to come together, it became padding.
== Zamin, pp. 191-192