Learn Hardcore Croatian: Vikendom spremamo stan zajedno. - On weekends we tidy the apartment together.

So you don’t say u vikendu or za vikend here, because vikendom by itself already functions like an adverb of time: “on weekends” as a general, repeated time frame.

Is there a difference between vikendom, za vikend, and svakog vikenda?

Yes, there are small nuances:

vikendom – “on weekends (in general)”
Habitual action; feels like a general statement about your routine.
- Vikendom spremamo stan. – On weekends we clean the apartment. (as a regular habit)
za vikend – “at/over the weekend”
Often refers to a specific upcoming or past weekend, but can also be used more generally in speech.
- Što radiš za vikend? – What are you doing this weekend?
svakog vikenda – “every weekend”
Explicitly stresses every single weekend.
- Svakog vikenda spremamo stan. – We clean the apartment every weekend. (emphasizes regularity)

In your sentence, vikendom nicely expresses a general routine.

How do I know that spremamo means “we clean/tidy” the apartment and not “we prepare” the apartment?

The verb spremati is flexible; its meaning depends on the object:

spremati stan / kuću / sobu – to tidy/clean the apartment/house/room
spremati ručak / večeru – to prepare lunch/dinner
spremati krevet – to make the bed
spremati se – to get ready (reflexive)

Because the object here is stan (apartment), the natural meaning in Croatian is “to clean / tidy / straighten up the apartment”, not “prepare the apartment.”

Context + typical collocations tell native speakers which meaning is intended.

What person and tense is spremamo, and how is spremati conjugated?

Spremamo is:

1st person plural (we)
present tense
imperfective aspect

The present tense of spremati (to tidy/prepare) is:

(ja) spremam – I tidy/prepare
(ti) spremaš – you tidy/prepare (sg.)
(on/ona/ono) sprema – he/she/it tidies/prepares
(mi) spremamo – we tidy/prepare
(vi) spremate – you tidy/prepare (pl./formal)
(oni/one/ona) spremaju – they tidy/prepare

Because it’s imperfective, spremamo describes an ongoing or habitual action (what you generally do on weekends).

Why is the subject pronoun mi (“we”) missing? Is that normal?

Yes, that’s completely normal in Croatian.

Croatian is a pro-drop language: subject pronouns (ja, ti, on, mi, etc.) are usually omitted because the verb ending already shows the person and number.

Spremamo stan. = We clean the apartment.
Mi spremamo stan. – also correct, but now mi is emphasized, like “We clean the apartment (not someone else).”

In your sentence, spremamo already clearly indicates “we,” so mi is not needed.

Why is stan in this form? Is it accusative, and why doesn’t it change?

Yes, stan here is in the accusative singular, because it is the direct object of spremamo (we tidy what? → the apartment).

For masculine inanimate nouns like stan, the accusative singular form is identical to the nominative:

Nominative: stan – apartment (subject)
Accusative: stan – apartment (object)

Compare:

Stan je velik. – The apartment is big. (nominative)
Spremamo stan. – We are cleaning the apartment. (accusative)

So it is accusative, even though it looks the same.

Could I say kuću instead of stan? What is the difference between stan and kuća?

You can, but the meaning changes slightly:

stan – apartment/flat (a unit inside a building)
kuća – house (a standalone building)

So:

Vikendom spremamo stan zajedno. – On weekends we tidy our apartment together.
Vikendom spremamo kuću zajedno. – On weekends we tidy our house together.

Both are grammatically correct; you choose the one that matches where you live.

What does zajedno add here, and where can it appear in the sentence?

Zajedno means “together” and tells us that the action is done jointly.

Position-wise, it’s quite flexible. All of these are natural, with only slight differences in emphasis:

Vikendom spremamo stan zajedno.
Vikendom zajedno spremamo stan.
Zajedno vikendom spremamo stan.

Placing zajedno near spremamo puts a bit more focus on the idea of doing it together, but all are correct. The version you have is very ordinary and idiomatic.

Can the word order be different, for example Stan spremamo vikendom zajedno?

Yes, Croatian word order is flexible, though not all variants sound equally neutral.

Grammatically possible versions include:

Vikendom spremamo stan zajedno. – neutral, very natural.
Vikendom zajedno spremamo stan. – also neutral, slightly more focus on “together.”
Stan spremamo vikendom zajedno. – still correct; now stan is fronted, which can emphasize the apartment (as opposed to something else).

Croatian relies heavily on intonation and context to interpret emphasis, while the basic roles (subject, object, etc.) are shown by endings, not just by position. As a learner, it’s safest to keep:

[Time] + [Verb] + [Object] + [Adverb]
→ Vikendom spremamo stan zajedno.

What is the aspect difference between spremamo and pospremimo or pospremamo?

Aspect in Croatian is very important:

spremati – imperfective
Focus on the process or habit:
- Vikendom spremamo stan. – On weekends we (habitually) tidy the apartment.
pospremiti / pospremamo / pospremimo – perfective
Focus on the completion of the action (to tidy up completely, finish tidying).
- Vikendom pospremimo stan. – On weekends we (manage to) tidy the apartment (get it done).

In a sentence describing a routine (“what we do on weekends”), the imperfective present (spremamo) is the natural choice. The perfective present (pospremimo) would more often appear in contexts like promises, plans, or sequences of actions.