Når rødderne vokser for meget, er det nødvendigt at skifte potte, så planten får mere jord.

Når means when, and here it introduces a situation that is expected or generally true.

So Når rødderne vokser for meget means when the roots grow too much.

A learner often compares når and hvis:

• når = when, for something that happens regularly, naturally, or is expected
• hvis = if, for something more uncertain or conditional

In this sentence, the plant’s roots growing too much is treated as a normal situation that can happen, so når is the natural choice.

Rødderne means the roots.

Danish adds the definite article to the end of the noun:

• rod = root
• rødder = roots
• rødderne = the roots

So the sentence is talking about the specific roots of the plant, not roots in general.

This is just part of the noun’s plural pattern.

• rod = root
• rødder = roots
• rødderne = the roots

The vowel changes from o to ø in the plural. English has similar irregular changes in some words, like foot → feet. So this is something you usually just learn as part of the word.

For meget means too much or too many, depending on context.

Here it means the roots are growing too much—in other words, more than is good for the pot.

A useful distinction is:

• meget = much / a lot
• for meget = too much

So vokser meget would mean grow a lot, but vokser for meget means grow too much.

Danish often uses the present tense for general truths, instructions, and situations that happen regularly.

So Når rødderne vokser for meget... is not only about what is happening right now. It can mean something like:

• When the roots get too big
• When the roots grow too much

This is very normal in both Danish and English for general statements.

This is because Danish is a V2 language in main clauses. That means the finite verb usually comes in the second position.

The sentence begins with a subordinate clause:

Når rødderne vokser for meget, ...

That whole clause takes the first position. So in the main clause, the finite verb must come next:

• Når rødderne vokser for meget, er det nødvendigt ...

Not:

• Når rødderne vokser for meget, det er nødvendigt ...

This word order is very important in Danish.

The det is a formal or anticipatory subject, similar to English it in sentences like:

• It is necessary to repot
• It is important to water the plant

So:

• er det nødvendigt at skifte potte = it is necessary to change pot / repot

The real content comes in the infinitive phrase at skifte potte, but Danish still uses det as the grammatical subject.

Nødvendig means necessary.

In this sentence it appears as nødvendigt because it agrees with det, which is grammatically neuter.

Compare:

• en nødvendig ændring = a necessary change
• det er nødvendigt = it is necessary

So the -t is the neuter/common predicative form that often appears after det er.

At skifte potte is an idiomatic Danish expression meaning to change pot or more naturally in English, to repot.

In Danish, some verb + noun combinations are used without an article, especially when the phrase describes a general activity rather than a specific object.

So:

• skifte potte = repot / change to a different pot

If you said skifte potten, it would sound more like replacing the pot as a specific known pot. That is possible in some contexts, but here the article-free phrase is the normal expression.

Yes. A very common verb is ompotte, which means to repot.

So the idea could also be expressed with at ompotte planten.

But skifte potte is perfectly understandable and natural, especially for learners because it is very transparent:

• skifte = change
• potte = pot

Here så means so that.

It introduces a purpose/result clause:

• så planten får mere jord = so that the plant gets more soil

This is not just the English conversational so at the beginning of a sentence. It connects the action of repotting with the result or purpose.

Because så here introduces a subordinate clause, and subordinate clauses in Danish usually have normal subject-verb order:

• planten får

not inverted order:

• får planten

So:

• ... så planten får mere jord = correct

This contrasts with the main clause earlier:

• ... er det nødvendigt ...

where Danish uses V2 word order.

Use mere with uncountable nouns and flere with countable plural nouns.

• jord = soil, earth, dirt, and it is uncountable here
• so: mere jord = more soil

Compare:

• mere vand = more water
• flere potter = more pots

So mere jord is the only natural choice here.

Because jord is being used as an uncountable material noun, like soil in English.

So Danish normally says:

• mere jord = more soil

not:

• mere en jord or mere jorden

If you used jorden, that would usually mean the earth/the ground/the soil in a more specific sense, which is not what is meant here.

Yes, in context får literally means gets, but the result is that the plant ends up with more soil available to it.

So in English you might translate it as:

• so the plant gets more soil
• so the plant has more soil
• so the plant has more room in the soil

The Danish verb is still får, which basically means gets/receives.

It has three parts:

1. Når rødderne vokser for meget

   • subordinate clause introduced by når
   • when the roots grow too much

2. er det nødvendigt at skifte potte

   • main clause
   • literally is it necessary to change pot
   • normal Danish V2 word order after the fronted subordinate clause

3. så planten får mere jord

   • subordinate clause introduced by så
   • so that the plant gets more soil

So the full structure is:

• When X happens, it is necessary to do Y, so that Z can happen.

That makes it a very useful model sentence for learning Danish clause order.