Når planterne er tørre, henter min søster vandkanden og vander jorden langsomt.

Når means when or whenever. In this sentence, it introduces a time clause:

Når planterne er tørre = When/Whenever the plants are dry

Danish often uses når for things that happen repeatedly or as a general rule. So the idea is not just one single moment, but something like: whenever the plants become dry, her sister fetches the watering can and waters the soil.

Planterne is the definite plural form, meaning the plants.

• en plante = a plant
• planter = plants
• planterne = the plants

So Når planterne er tørre means When the plants are dry, not just when plants are dry in a general abstract sense.

Because planterne is plural.

In Danish, adjectives often agree with the noun they describe:

• planten er tør = the plant is dry
• planterne er tørre = the plants are dry

So tørre is the plural form of tør here.

This is a very common Danish word order pattern.

The sentence begins with a subordinate clause:

Når planterne er tørre

After that, the main clause must follow the verb-second rule. That means the finite verb comes before the subject if something else is already in first position.

So:

1. Når planterne er tørre = first element
2. henter = finite verb
3. min søster = subject

That is why Danish says:

Når planterne er tørre, henter min søster vandkanden...

and not:

Når planterne er tørre, min søster henter...

This is one of the most important Danish word order rules to learn.

Henter means fetches, gets, or goes to get.

So min søster henter vandkanden means:

• my sister fetches the watering can
• or my sister gets the watering can

It suggests she goes and gets it before watering.

Vandkanden means the watering can.

The noun is:

• en vandkande = a watering can
• vandkanden = the watering can

The ending -n is a common way to make an en-word definite in Danish.

Because the subject is still the same.

In English, we also often do this:

My sister fetches the watering can and waters the soil slowly.

We do not need to repeat my sister before waters, because it is clearly the same person doing both actions.

The same happens in Danish:

henter min søster vandkanden og vander jorden langsomt

Both henter and vander refer to min søster.

Vander means waters.

• at vande = to water
• vander = waters / is watering

So vander jorden means waters the soil/ground.

You could also express the idea with something involving vand (water), but vande is the normal verb for watering plants or soil. It is the most natural choice here.

Jorden means the soil or the ground.

The noun is:

• jord = soil / earth / ground
• jorden = the soil / the ground

Here, Danish uses the definite form because it refers to the soil in that specific situation: the soil around the plants.

It can, depending on context.

jord can mean:

• soil
• ground
• earth

And Jorden with a capital letter can mean the Earth as a planet.

In this sentence, because we are talking about plants and watering, jorden clearly means the soil or the ground, not the planet.

Because here it is an adverb, not an adjective.

• langsom = slow
• langsomt = slowly

In the sentence, langsomt describes how she waters:

vander jorden langsomt = waters the soil slowly

A common pattern in Danish is that an adjective gets -t when used adverbially:

• hurtig = fast
• hurtigt = quickly
• langsom = slow
• langsomt = slowly

Yes. Er is the present tense of at være (to be).

So:

• planten er tør = the plant is dry
• planterne er tørre = the plants are dry

The whole sentence is in the present tense, which is very natural for habits, routines, and general situations in Danish.

Yes, absolutely.

In this sentence, Når planterne er tørre can be understood as either:

• When the plants are dry
• Whenever the plants are dry

Because the meaning is about a repeated situation, whenever is often a very good English translation.

Yes. That is the most natural interpretation.

The present tense in Danish often describes:

• habits
• routines
• repeated actions
• general truths

So this sentence sounds like a regular pattern:

Whenever the plants are dry, my sister fetches the watering can and waters the soil slowly.

It does not have to mean she is doing it at this exact moment.

The subject of the main clause is min søster.

The sentence has two parts:

1. Når planterne er tørre

   • here the subject is planterne

2. henter min søster vandkanden og vander jorden langsomt

   • here the subject is min søster

So there are actually two clauses, and each clause has its own subject.

Yes. Min søster means my sister, and possessives like min already make the noun definite in meaning.

So Danish does not say something like min søsteren.

You say:

• min søster = my sister
• not min søsteren

This is similar to English, where my sister is already specific and does not need the.