Om potatisen är skalad, kan vi koka den nu.

Because potatisen is the definite form of potatis.

• potatis = potato / potatoes, in a general sense
• potatisen = the potato / the potatoes, depending on context

In Swedish, definiteness is often shown by adding an ending to the noun instead of using a separate word like the.

Here, potatisen means something like the potato or the potatoes that both speakers already know about.

The word potatis is often treated as a mass noun or a collective noun in Swedish, especially when talking about potatoes as food rather than counting individual items.

So potatisen can mean:

• the potato in a singular sense, or
• the potatoes as a known batch of potatoes

Context tells you which meaning is intended.

This is very natural in Swedish. English often forces you to choose between singular and plural more clearly than Swedish does.

Om means if in this sentence.

So:

• Om potatisen är skalad = If the potato / potatoes are peeled

A common beginner point: om can also mean about in other contexts.

For example:

• Vi pratar om Sverige = We are talking about Sweden

So the meaning of om depends on context.

Swedish often forms this idea with är + a past participle.

• är = is / are
• skalad = peeled

So är skalad literally means is peeled or is in a peeled state.

This is similar to English:

• The potato is peeled

It describes a resulting state, not the action itself.

Compare:

• Vi skalar potatisen = We peel the potato / potatoes
  (action)
• Potatisen är skalad = The potato / potatoes are peeled
  (state/result)

Because the form of the adjective/past participle agrees with the noun.

Potatis is an en-word and here it is treated as singular/common gender, so the form is:

• skalad

Compare:

• ett äpple är skalat = an apple is peeled
• äpplena är skalade = the apples are peeled

So the pattern is roughly:

• en-word singular → skalad
• ett-word singular → skalat
• plural / definite plural → skalade

Because Swedish follows the V2 rule in main clauses: the finite verb must come in the second position.

The sentence begins with a subordinate clause:

• Om potatisen är skalad

After that, the main clause starts:

• kan vi koka den nu

The finite verb kan must come first in the main clause because the whole if-clause has taken the first position.

So the structure is:

• Om potatisen är skalad, kan vi koka den nu.

If you start directly with the main clause, then you get:

• Vi kan koka den nu om potatisen är skalad.

Both are correct.

Because om potatisen är skalad is a subordinate clause, and subordinate clauses do not use the same V2 pattern as main clauses.

Inside the subordinate clause, the normal order is:

• om
  • subject + verb + complement
• om potatisen är skalad

So:

• potatisen = subject
• är = verb
• skalad = complement

This is more similar to ordinary English word order.

Because potatis is an en-word, and the pronoun must match the noun’s grammatical gender.

• en potatis → den
• ett äpple → det

So:

• potatisen ... den is correct

Even though English uses it, Swedish has to choose between den and det.

Yes. In this sentence, den means it.

It refers back to potatisen.

So:

• kan vi koka den nu = can we boil/cook it now

For things, Swedish uses:

• den for en-words
• det for ett-words

Koka usually means boil.

In this sentence, it most naturally means:

• boil it now or
• cook it now by boiling

With potatoes, koka potatis is a very common phrase meaning boil potatoes.

So while the broad idea may be cook, the specific method is boil.

Kan often means can, but not only in the sense of physical ability. It can also mean:

• can
• may
• be able to

Here, kan vi koka den nu most naturally means something like:

• Can we boil it now?
• Are we able to / is it possible to boil it now?

Depending on context, it may also sound like:

• May we boil it now?
• Is it okay to boil it now?

So Swedish kan can cover several meanings that English sometimes separates.

Yes, absolutely.

That version is also correct:

• Vi kan koka den nu om potatisen är skalad.

The difference is mainly focus and style.

• Om potatisen är skalad, kan vi koka den nu.
  This puts the condition first: If the potato is peeled...

• Vi kan koka den nu om potatisen är skalad.
  This starts with the main idea: We can boil it now...

Both are natural.

Not always.

In Swedish, a comma after an initial subordinate clause is often optional, especially in short, clear sentences.

So both of these are possible:

• Om potatisen är skalad, kan vi koka den nu.
• Om potatisen är skalad kan vi koka den nu.

The comma can help readability, but Swedish generally uses fewer commas than English.

Nu means now, and its position can move somewhat depending on emphasis.

In your sentence:

• kan vi koka den nu

That is very natural.

You may also see:

• Nu kan vi koka den = Now we can boil it
• Kan vi nu koka den? = Can we boil it now? with more focus on now

So nu is flexible, but the exact position can slightly change the emphasis or rhythm.

Without the if-clause, the main clause would be:

• Vi kan koka den nu. = We can boil it now.

Adding the condition gives:

• Om potatisen är skalad, kan vi koka den nu.

So the sentence is built from:

1. a condition: Om potatisen är skalad
2. a main clause: kan vi koka den nu

This is a useful pattern in Swedish:

• Om X, kan vi Y
• If X, we can Y

It is best understood here as a past participle used like an adjective.

That is why it behaves a lot like an adjective and agrees with the noun:

• skalad
• skalat
• skalade

This is very common in Swedish.

So in practice, you can think of är skalad as:

• a passive/result-state expression
• built with to be
  • participle
• functioning similarly to an adjective

English does the same thing in sentences like:

• The door is closed
• The potato is peeled