Learn Hardcore German: Zu Hause herrscht Ruhe, wenn die Kinder sich nicht mehr streiten. - At home there is calm when the children no longer argue.

im Haus = “in the building/house” (very literal, could be any house, e.g. a school building).
bei mir = “at my place / at my house” (emphasizes my location, not necessarily “home” as an abstract idea).
zu Hause = “(at) home” as a general state/location.

So Zu Hause herrscht Ruhe is best understood as “At home, it is quiet / there is peace,” not just “inside the building.”

Why is zu Hause written with a capital H? Can it also be zuhause?

Official standard spelling (per Duden) is:

zu Hause when it functions as an adverb (“at home”)
(das) Zuhause as a noun (“the home”)

However, you also often see zuhause (one word, all lowercase) in everyday writing, and it is widely accepted in modern usage.

In your sentence, Zu Hause is an adverbial (“at home”), so zu Hause is the textbook spelling. The Z is capitalized only because it’s at the beginning of the sentence.

What does herrscht Ruhe literally mean, and why not just say es ist ruhig?

The verb herrschen literally means “to rule, to reign, to prevail.”

Ruhe herrscht. = “Silence/peace prevails.”
Zu Hause herrscht Ruhe. = “At home, peace/quiet prevails.”

You could say:

Zu Hause ist es ruhig. = “At home, it is quiet.”

Both are correct, but the nuance is different:

herrscht Ruhe sounds a bit more expressive or stylistic, as if peace is the dominant “force” there.
es ist ruhig is more neutral, purely descriptive.

So the sentence slightly emphasizes the state that takes over the house when the kids stop arguing.

Why is the word order Zu Hause herrscht Ruhe and not Zu Hause Ruhe herrscht?

German main clauses follow the V2 rule: the finite verb (here herrscht) must be in second position in the sentence field.

Zu Hause is an adverbial phrase and occupies position 1.
The finite verb herrscht must then come in position 2.
The subject Ruhe follows after the verb.

So:

Position 1: Zu Hause
Position 2: herrscht (finite verb)
Rest: Ruhe (subject)

That’s why Zu Hause herrscht Ruhe is correct and Zu Hause Ruhe herrscht would sound wrong in standard word order.

Why is there a comma before wenn, and why does the verb streiten go to the end?

Wenn introduces a subordinate clause. In German:

A subordinate clause is separated from the main clause by a comma.
In subordinate clauses, the finite verb goes to the end.

So we have:

Main clause: Zu Hause herrscht Ruhe,
Subordinate clause: wenn die Kinder sich nicht mehr streiten.

Inside the wenn-clause:

Subject: die Kinder
Other elements: sich nicht mehr
Finite verb at the end: streiten

Hence the order: wenn die Kinder sich nicht mehr streiten.

Why is wenn used here and not als or wann?

German distinguishes:

wenn
- for repeated or general situations (whenever, when)
- also for conditions (if/when)
- Example: Wenn es regnet, bleibe ich zu Hause. – “When(ever) it rains, I stay home.”
als
- for a single, completed event in the past
- Example: Als ich klein war, spielte ich viel draußen. – “When I was small, I played outside.”
wann
- for questions about at what time
- Example: Wann kommst du? – “When are you coming?”

In your sentence, we have a general condition/habitual situation:

“At home, it is quiet when the kids are no longer arguing (whenever that is the case).”

So wenn is correct. Als would be wrong here, and wann would only be used in a question like Wann herrscht zu Hause Ruhe?

What exactly does nicht mehr mean here, and how is it different from just nicht?

nicht alone = “not” (simple negation)
nicht mehr = “no longer / not anymore”

So:

wenn die Kinder sich nicht streiten
= “when the children do not argue (at all)” – a simple negation of arguing.
wenn die Kinder sich nicht mehr streiten
= “when the children no longer argue / when they don’t argue anymore” – it implies they used to argue, but then they stop.

Mehr in nicht mehr is not “more” in the positive sense here; together they form a fixed expression meaning “anymore / no longer.”

Why do we say sich streiten and not just streiten? What is sich doing?

Sich streiten is a reflexive verb in German and means “to argue (with each other), to quarrel.”

streiten by itself can mean “to argue, to dispute” in a more general or transitive way (e.g. über etwas streiten – argue about something).
sich streiten focuses on people arguing with each other.

In your sentence:

die Kinder = the children (subject)
sich = reflexive pronoun referring back to the subject (“themselves/each other”)
sich streiten = “argue (with each other)”

So wenn die Kinder sich nicht mehr streiten means: “when the children no longer argue (with each other).” The sich makes it clear that they are mutually involved in the argument.

Why is the reflexive pronoun sich placed after die Kinder and before nicht mehr streiten?

In a subordinate clause, the general order in the middle field is:

Subject
(Reflexive/object pronouns)
Other adverbials / negation
Non-finite verbs at the end

So we get:

Subject: die Kinder
Reflexive pronoun: sich
Negation + temporal adverb: nicht mehr
Verb at the end: streiten

→ … wenn die Kinder sich nicht mehr streiten.

You cannot put sich after the verb:

❌ wenn die Kinder nicht mehr streiten sich – wrong.

You sometimes also hear/see wenn sich die Kinder nicht mehr streiten; that’s also correct. In your version, the subject die Kinder just comes first, which is very natural.

Why is it Ruhe, a noun, instead of the adjective ruhig?

German often uses a noun + herrschen construction:

Ruhe herrscht. – “There is peace/quiet.”
Chaos herrscht. – “There is chaos.”
Ordnung herrscht. – “There is order.”

Here, Ruhe is a noun meaning “peace, quiet, calm.” Using the noun with herrschen sounds like a state that prevails in that place.

If you used the adjective:

Zu Hause ist es ruhig.

you would be stating it more neutrally: “At home, it is quiet.”
With Ruhe herrscht, the style is a bit more vivid and idiomatic, almost like saying “Peace reigns at home.”

Shouldn’t it be future tense in German, like “when the kids will not argue anymore”?

In German, for future meaning in time clauses with wenn, the present tense is usually used:

Ich rufe dich an, wenn ich zu Hause bin.
= “I’ll call you when I am at home.” (literally present-present)

Using werden for the future here would sound unnatural:

❌ wenn ich zu Hause sein werde – rarely used, usually only to stress something special.

So:

Zu Hause herrscht Ruhe, wenn die Kinder sich nicht mehr streiten.

can refer to a general fact, a habitual situation, or even a future situation depending on context. German present tense is flexible that way; you don’t need a special future form in this kind of wenn-clause.