Zemlja u vrtu je mokra poslije kiše.

Zemlja can mean several things in Croatian, including earth, soil, ground, land, or even country, depending on context.

In this sentence, because it says u vrtu and poslije kiše, zemlja clearly means soil/ground.

So here it means something like:

• the soil
• the ground
• the earth (in the sense of dirt, not the planet)

Croatian does not have articles like English a/an/the.

So zemlja u vrtu je mokra can mean:

• the soil in the garden is wet
• or sometimes just soil in the garden is wet

English usually needs an article, but Croatian does not. Definiteness is understood from context.

Zemlja is the subject of the sentence, so it is in the nominative case.

The sentence structure is basically:

• Zemlja = subject
• je mokra = is wet

The form zemlju would be accusative, which you would use if earth/soil were a direct object, not the subject.

Example:

• Zemlja je mokra. = The soil is wet.
• Vidim zemlju. = I see the ground/soil.

Because u can take different cases depending on meaning:

• u + locative = location, in
• u + accusative = motion toward, into

Here the sentence describes where the soil is located: in the garden. There is no movement, so Croatian uses the locative:

• u vrtu = in the garden

Compare:

• Zemlja je u vrtu. = The soil is in the garden.
• Idem u vrt. = I’m going into the garden.

So:

• u vrtu = location
• u vrt = destination

Because after u meaning in, the noun must be in the locative case.

The noun is:

• dictionary form: vrt = garden

Locative singular:

• u vrtu = in the garden

This is a normal case ending for many masculine nouns.

Croatian adjectives must agree with the noun they describe in:

• gender
• number
• case

The noun zemlja is:

• feminine
• singular
• nominative

So the adjective must also be feminine singular nominative:

• masculine: mokar
• feminine: mokra
• neuter: mokro

That is why the sentence has:

• Zemlja je mokra.

Compare:

• Vrt je mokar. = The garden is wet.
• Tlo je mokro. = The ground/soil is wet.

Je is the 3rd person singular present tense of the verb biti = to be.

So here:

• je = is

The structure is:

• Zemlja = the soil
• je = is
• mokra = wet

So literally:

• Zemlja je mokra. = The soil is wet.

Because poslije meaning after normally requires the genitive case.

The noun is:

• kiša = rain

Its genitive singular is:

• kiše

So:

• poslije kiše = after the rain

This is very common in Croatian:

• poslije ručka = after lunch
• poslije škole = after school
• poslije kiše = after the rain

Yes. Nakon kiše is also correct and natural.

Both mean:

• after the rain

Very roughly:

• poslije is very common in everyday speech
• nakon can sound a bit more formal or neutral in some contexts

In this sentence, both work well:

• Zemlja u vrtu je mokra poslije kiše.
• Zemlja u vrtu je mokra nakon kiše.

Croatian word order is more flexible than English because cases show grammatical relationships.

This sentence has a neutral, natural order:

• Zemlja u vrtu je mokra poslije kiše.

But other orders are also possible, depending on emphasis:

• Poslije kiše zemlja u vrtu je mokra.
  Emphasis on after the rain
• Mokra je zemlja u vrtu poslije kiše.
  More marked or stylistic

So yes, the word order can change, but the original version sounds very normal and straightforward.

Croatian uses different prepositions depending on how a place is conceptualized.

For garden, Croatian normally says:

• u vrtu = in the garden

The preposition na is used for surfaces, events, institutions, and certain fixed expressions, but vrt is normally treated as a space you are in, not a surface you are on.

So:

• u vrtu = correct and natural
• na vrtu = not the normal choice here

A few sounds may stand out to English speakers:

• ž in zemlja, kiše
  sounds like the s in measure
• š in kiše
  sounds like sh in shoe
• lj in zemlja, poslije
  is a single sound, somewhat like the lli in million for many English speakers

A rough pronunciation guide:

• Zemlja ≈ ZEM-lya
• u vrtu ≈ oo VR-too
• je ≈ ye
• mokra ≈ MO-kra
• poslije ≈ POS-lye
• kiše ≈ KEE-she

This is only approximate, but it helps as a starting point.

Mokra usually means wet.

If you want damp or moist, Croatian often uses:

• vlažna

So:

• mokra zemlja = wet soil
• vlažna zemlja = damp/moist soil

In your sentence, mokra suggests the soil is properly wet, which fits well with poslije kiše.