När hon hade vattnat varje kruka, satte hon sig på balkongen och bläddrade i en roman.

Because Swedish can begin a sentence with a time clause, just like English can:

• När hon hade vattnat varje kruka, satte hon sig ...
• When she had watered every pot, she sat down ...

Starting with När ... puts the time/background first. It sounds natural and often helps set the scene before the main action.

Hade vattnat is the past perfect (also called the pluperfect). It shows that this action happened before another action in the past.

In this sentence:

• hade vattnat = she had watered
• satte / bläddrade = she sat down / leafed through

So the order is:

1. she watered all the pots
2. then she sat on the balcony and leafed through a novel

That is why hade vattnat is used instead of simple past vattnade.

It is made with:

• hade = had
• the supine form of the verb = vattnat

So:

• vattna = to water
• vattnade = watered / was watering
• har vattnat = has watered
• hade vattnat = had watered

This is a very common Swedish pattern:

• har + supine = present perfect
• hade + supine = past perfect

Because varje means each or every, and in Swedish it is followed by a singular indefinite noun.

So you say:

• varje kruka = each pot / every pot
• varje dag = every day
• varje bok = every book

Not:

• varje krukor
• varje dagar

This is different from some English expressions, where learners may expect a plural idea because the meaning is plural overall.

This is because of the Swedish V2 rule.

In a Swedish main clause, the finite verb must come in the second position. When the sentence begins with something other than the subject—here, the whole time clause När hon hade vattnat varje kruka—the verb comes before the subject in the main clause.

So:

• first element: När hon hade vattnat varje kruka
• second position: satte
• then subject: hon

That gives:

• När hon hade vattnat varje kruka, satte hon sig ...

If the sentence started directly with the subject, then it would be:

• Hon satte sig på balkongen ...

The verb is sätta sig, which means to sit down.

Literally, it is something like set oneself, but you should learn it as a fixed reflexive verb:

• sätta sig = to sit down
• hon satte sig = she sat down

The word sig is the reflexive pronoun, meaning herself/himself/itself/themselves depending on context.

Compare:

• sätta = to put / set something
• sätta sig = to sit down

So sig is necessary here.

They are related, but they do not mean the same thing.

• satte sig = sat down
  This describes the action of moving into a sitting position.
• satt = sat / was sitting
  This describes the state of already being seated.

Examples:

• Hon satte sig på balkongen. = She sat down on the balcony.
• Hon satt på balkongen. = She was sitting on the balcony.

So in your sentence, satte hon sig shows the change of action: first she finished watering, then she sat down.

Because på is used for being on a balcony, just as in English.

• på balkongen = on the balcony

Using i would usually mean in, which does not fit here.

Swedish often uses location prepositions similarly to English, but not always, so this is a phrase worth learning as a chunk:

• på balkongen
• på terrassen
• på verandan

The verb bläddra means to leaf through, flip through, or sometimes browse through pages.

It is often used with the preposition i:

• bläddra i en bok = leaf through a book
• bläddra i en tidning = flip through a magazine/newspaper
• bläddra i en roman = leaf through a novel

So i belongs naturally with this expression.

It does not necessarily mean she was reading the whole novel carefully; it suggests looking through the pages.

Because the verb bläddra commonly takes the preposition i when talking about what you leaf through.

So the pattern is:

• bläddra i + something

Examples:

• bläddra i en bok
• bläddra i katalogen
• bläddra i romanen

This is similar to how some English verbs need a particular preposition, even when it may not be fully predictable.

En roman means a novel, while romanen means the novel.

The indefinite form en roman is used because the novel is being introduced without specifying which one. If the context already made it clear which novel it was, Swedish could use the definite form:

• bläddrade i en roman = leafed through a novel
• bläddrade i romanen = leafed through the novel

So the indefinite form is natural if the novel is not previously known or identified.

Because both verbs belong to the same subject, and Swedish often leaves the subject unstated in the second part when clauses are joined by och.

So:

• satte hon sig på balkongen och bläddrade i en roman

means:

• she sat down on the balcony and she leafed through a novel

The second hon is understood. Swedish does this just like English often does:

• She sat down and leafed through a novel.

Yes. They are both in the simple past:

• satte = sat down
• bläddrade = leafed through / flipped through

So the sentence combines:

• past perfect for the earlier action: hade vattnat
• simple past for the later actions: satte, bläddrade

This sequence is very common in storytelling.

Here När is a subordinating conjunction meaning when. It introduces a subordinate clause:

• När hon hade vattnat varje kruka

That whole part gives the time background for the main clause.

A useful point: in subordinate clauses, Swedish word order is different from main-clause V2 word order. That is why hon hade vattnat has the normal subject-verb order inside the När clause.

The comma before the main clause is natural and helpful here, especially because the sentence begins with a subordinate clause:

• När hon hade vattnat varje kruka, satte hon sig ...

In modern Swedish, comma use is sometimes a bit less strict than in English, but this comma is perfectly standard and makes the structure clearer.

So even if you may sometimes see Swedish with fewer commas, this one is very normal.