Learn Hardcore German: Auf dem Bauernhof stinkt nur die alte Mülltonne hinter dem Stall. - On the farm only the old trash bin behind the stable stinks.

Wir fahren auf den Bauernhof. – We’re driving onto the farm. (movement → accusative)
Wir sind auf dem Bauernhof. – We’re on/at the farm. (location → dative)

Why does the verb stinkt come right after Auf dem Bauernhof?

German main clauses follow the verb-second (V2) rule: the conjugated verb must be in second position in the sentence.

Auf dem Bauernhof = 1st position (one clause element, even though it has three words)
stinkt = 2nd position (the finite verb – required by the V2 rule)

After that, the rest of the elements follow in a relatively flexible order:

Auf dem Bauernhof stinkt nur die alte Mülltonne hinter dem Stall.

You could also start with the subject and still keep V2:

Die alte Mülltonne hinter dem Stall stinkt nur auf dem Bauernhof.

What exactly does nur do here, and why is it before die alte Mülltonne?

nur means only and works as a focus particle. It limits what part of the sentence is being talked about.

Placed before die alte Mülltonne, it focuses that noun phrase:

nur die alte Mülltonne = only the old trash can (and nothing/no one else)

If you moved nur, the meaning changes:

Auf dem Bauernhof stinkt nur die alte Mülltonne…
→ Only the trash can stinks (nothing else on the farm stinks).
Auf dem Bauernhof stinkt die alte Mülltonne nur hinter dem Stall.
→ The trash can stinks only when it is behind the barn (other locations: no).

So nur usually stands right in front of the word or phrase it limits. Here, we want to say that the trash can is the only smelly thing, so nur goes before die alte Mülltonne.

Why is it die alte Mülltonne and not die alten Mülltonne?

Look at the gender, number, and case:

Mülltonne is feminine: die Mülltonne
It’s singular
In this sentence, it is the subject → nominative case

With a definite article (die) in feminine nominative singular, the adjective ending is -e:

die alte Mülltonne
article: die
adjective: alt → alte
noun: Mülltonne

die alten Mülltonnen would be plural (the old trash cans).

How do we know that die alte Mülltonne is the subject?

Ask the typical subject question in German: Wer oder was stinkt? (Who or what stinks?)

Answer: die alte Mülltonne.

Other clues:

It agrees in number (singular) with the verb stinkt (3rd person singular).
Its article form die and adjective ending -e fit nominative feminine singular, which is the normal case for a subject.

Why is it hinter dem Stall and not hinter den Stall?

Like auf, hinter is a two-way preposition (Wechselpräposition):

With accusative for movement to a position
With dative for a fixed location

Here, the trash can is located behind the barn (no movement), so we need the dative:

der Stall (nominative)
dem Stall (dative singular masculine)

So: hinter dem Stall = behind the barn (as a location)

Compare:

Er geht hinter den Stall. – He walks behind the barn (movement → accusative)
Er steht hinter dem Stall. – He stands behind the barn (location → dative)

Why is the verb form stinkt and not stinken or something else?

The infinitive is stinken (“to stink”).
We need the form for 3rd person singular present (it stinks):

ich stinke
du stinkst
er/sie/es stinkt
wir stinken
ihr stinkt
sie/Sie stinken

The subject die alte Mülltonne is 3rd person singular, so the correct form is stinkt.

What is the difference between stinken and riechen?

Both relate to smell, but:

stinken = to stink, to smell bad (strongly negative)
- Die Mülltonne stinkt.
riechen = to smell, neutral; can be good or bad, depending on context
- Die Blumen riechen gut.
- Das riecht schlecht.

So in this sentence, we want to say that the trash can smells bad, therefore stinkt is used, not riecht.

Why is it Auf dem Bauernhof and not In dem Bauernhof or Bei dem Bauernhof?

All three prepositions exist, but they have different typical uses:

auf dem Bauernhof
→ standard way to say “on/at the farm” (as a place where work and life happen)
in dem Bauernhof
→ inside the building of the farm (less common; you normally say im Haus instead)
bei dem Bauernhof
→ “near/by the farm” or “at the farm (company)” in some contexts

In everyday German, when you mean “on the farm” as a place, you almost always say auf dem Bauernhof.

Why is Bauernhof one word instead of Bauern Hof?

German loves compound nouns. Two nouns are often joined into one new word:

der Bauer (farmer) + der Hof (yard, courtyard)
→ der Bauernhof (farm)

When the first part is grammatically linked, it may take a special form:

Bauer → Bauern in Bauernhof (like a linking form)

So Bauernhof is correct as one word. Writing it as Bauern Hof would be wrong.

What are the genders and plurals of Bauernhof, Mülltonne, and Stall?

der Bauernhof (masculine)
plural: die Bauernhöfe
die Mülltonne (feminine)
plural: die Mülltonnen
der Stall (masculine)
plural: die Ställe

In the sentence:

dem Bauernhof = dative singular of der Bauernhof
die alte Mülltonne = nominative singular of die Mülltonne
dem Stall = dative singular of der Stall

Could we change the word order, and would the meaning change?

Yes, German allows several word orders while keeping roughly the same meaning, as long as:

the finite verb stays in position 2
the subject–verb agreement remains correct

Examples (all grammatical, slightly different emphasis):

Auf dem Bauernhof stinkt nur die alte Mülltonne hinter dem Stall.
– Neutral; emphasizes what happens on the farm first.
Nur die alte Mülltonne hinter dem Stall stinkt auf dem Bauernhof.
– Stronger focus on only the trash can.
Die alte Mülltonne hinter dem Stall stinkt nur auf dem Bauernhof.
– Suggests it stinks only on the farm (elsewhere maybe not).

So changing the order is possible, but be careful: shifting nur can also shift the meaning, not just the rhythm.