W garażu stoi jeszcze jeden karton z książkami, którego nie mam kiedy rozpakować.

Polish word order is flexible, and starting with the place is very natural when you are introducing or locating something.

So W garażu stoi jeszcze jeden karton... sounds like:

• first: where it is
• then: what is there

This is especially common in sentences that feel a bit like There is/There stands... in English.

You could also say Jeszcze jeden karton stoi w garażu..., but that would put more emphasis on the box rather than on the garage.

In Polish, physical objects are often described with position verbs:

• stoi = is standing
• leży = is lying
• wisi = is hanging

A box is something Polish commonly treats as standing, so stoi sounds natural.

Jest w garażu is possible, but it is more neutral and less vivid. Stoi w garażu tells you not only that it is there, but also presents it as a physical object placed there.

Garażu is in the locative singular.

That is because after w meaning in, when you talk about a fixed location, Polish uses the locative:

• w garażu = in the garage
• w domu = in the house
• w szkole = at school / in school

So here:

• garaż = basic form
• w garażu = locative after w

Here jeszcze jeden means one more, another, or sometimes yet another.

It suggests that there is already at least one other box, and this is an additional one.

A useful point:

• jeszcze by itself often means still or yet
• but with a numeral, like jeden, it often means one more / another

So:

• jeszcze jeden karton = one more box / another box

Karton z książkami means a box with books in it.

This is a very natural way in Polish to describe the contents of a container: z + instrumental.

So:

• karton z książkami = a box with books
• torba z ubraniami = a bag with clothes
• szafka z naczyniami = a cabinet with dishes

A form like karton książek is also possible in some contexts, but it sounds more like a quantity expression, similar to a carton/box of books. In this sentence, z książkami is the more straightforward description of what is inside the box.

Because książkami is the instrumental plural form of książki.

Here z means with, and z in that meaning takes the instrumental:

• z książkami = with books
• z dziećmi = with children
• z przyjaciółmi = with friends

So the pattern is:

• książki = books
• z książkami = with books

Be careful: z does not always take the same case. For example:

• z książkami = with books → instrumental
• z garażu = from the garage → genitive

Because the subject is karton, not książkami.

The phrase z książkami only describes the box. It does not control the verb.

So the structure is:

• karton = the thing doing the standing
• z książkami = extra information about that box

That is why the verb is singular:

• stoi = singular, matching karton

Yes, literally it is close to I don’t have when, but in natural English it means something like:

• I don’t have time to...
• I don’t have a chance to...
• I can’t find a moment to...

This is a very common Polish expression.

So:

• nie mam kiedy rozpakować = I don’t have time / a moment to unpack

Compared with nie mam czasu, nie mam kiedy often focuses more on not having a suitable moment or opportunity in your schedule.

Because którego is the form required by the relative clause.

A relative pronoun like który works in two ways at once:

1. it agrees with the noun it refers to in gender and number
2. its case depends on its role inside the relative clause

Here it refers back to karton, so it must be:

• masculine singular

But inside the clause którego nie mam kiedy rozpakować, Polish uses the genitive in this pattern:

• nie mam kiedy rozpakować kartonu

Since kartonu is genitive, the relative pronoun is also genitive:

• którego

So:

• karton → masculine singular noun being referred to
• którego → masculine singular genitive form of który

It refers to karton.

A good way to see that is to check gender and number:

• karton is masculine singular
• książkami is plural

The form którego is singular masculine/neuter genitive, so it matches karton, not książkami.

So the meaning is: the box that I do not have time to unpack.

Because którego introduces a relative clause, and in Polish such clauses are normally separated by a comma.

So:

• karton z książkami, którego nie mam kiedy rozpakować

The part after the comma gives extra information about karton.

This is standard Polish punctuation with który, która, które, etc.

Rozpakować is perfective, so it focuses on a completed action: unpacking the box fully.

That fits the sentence well, because the idea is not about the general process of unpacking, but about getting this one task done.

• rozpakować = unpack completely
• rozpakowywać = be unpacking / unpack repeatedly / focus on process

So here Polish naturally uses the perfective form for a single unfinished task.

If you used rozpakowywać, it would sound more process-oriented.

Yes, you could.

For example:

• ...karton z książkami, którego nie mam czasu rozpakować
• ...karton z książkami, którego nie mam kiedy rozpakować

Both are understandable and natural.

The difference is small:

• nie mam czasu = I don’t have time
• nie mam kiedy = I don’t have a moment / no suitable time slot

In this sentence, nie mam kiedy sounds especially natural because it suggests everyday busyness: there is simply no moment when the unpacking can happen.