Meine Schwester pflanzt Tulpen ins Beet hinter dem Haus, weil dort genug Sonne ist.

Meine Schwester is the subject of the sentence, so it is in the nominative case.

• meine Schwester = my sister (subject)
• meinen would be an accusative masculine form, so it would not fit Schwester, which is feminine

Here, meine is the correct nominative feminine form of mein.

German often leaves out the article when talking about plural nouns in a general or indefinite way.

So:

• Tulpen = tulips
• die Tulpen would mean the tulips (specific tulips)

In this sentence, Tulpen just means she is planting tulips, not a particular already-known set of tulips.

Tulpen is in the accusative case because it is the direct object of pflanzt.

Ask yourself: what is she planting?

• She is planting Tulpen

So Tulpen is the thing directly affected by the action.

In the plural, the form Tulpen looks the same in both nominative and accusative, so you identify the case by its role in the sentence, not by the ending.

Ins is a contraction of in das.

• in das Beet → ins Beet

German uses this contraction very commonly.

Also, in is a two-way preposition:

• accusative for motion toward/into
• dative for location

Here, the sister is planting the tulips into the flowerbed, so there is movement/change of location. That is why German uses the accusative:

• ins Beet = into the flowerbed

These are two different words:

• das Beet = flowerbed / garden bed
• das Bett = bed (the thing you sleep in)

They look similar, but they mean very different things. In a gardening sentence, Beet is the correct word.

Because this part describes a location, not movement.

German two-way prepositions such as hinter take:

• dative for location
• accusative for motion toward a place

Here, hinter dem Haus tells you where the flowerbed is:

• the flowerbed is behind the house

There is no movement in hinter dem Haus itself. The movement is in ins Beet, not in behind the house.

So:

• hinter dem Haus = location → dative
• hinter das Haus would suggest movement to behind the house

It modifies Beet.

So the structure is basically:

• ins Beet
• hinter dem Haus

Together, this means:

• into the flowerbed behind the house

The phrase hinter dem Haus tells us which flowerbed we mean.

Because weil introduces a subordinate clause, and in German, subordinate clauses are separated by a comma.

Main clause:

• Meine Schwester pflanzt Tulpen ins Beet hinter dem Haus

Subordinate clause:

• weil dort genug Sonne ist

The comma is required in standard German punctuation.

Because weil is a subordinating conjunction.

In German, subordinating conjunctions such as weil, dass, wenn, and obwohl send the conjugated verb to the end of the clause.

So instead of:

• dort ist genug Sonne

you get:

• weil dort genug Sonne ist

That final ist is a very common feature of German subordinate clauses.

Dort means there.

In this sentence, it refers to the place already mentioned, basically behind the house / in that spot.

So:

• weil dort genug Sonne ist = because there is enough sun there

German often uses dort to point back to a place just mentioned.

Because Sonne here is being used as an uncountable noun in a general sense.

• genug Sonne = enough sun / enough sunlight

German often omits the article with abstract or mass nouns in this kind of expression.

Compare:

• genug Zeit = enough time
• genug Geld = enough money
• genug Sonne = enough sun

You would not normally say genug die Sonne here.

The main clause follows the standard German verb-second pattern.

• Meine Schwester = position 1
• pflanzt = position 2
• everything else follows

So the structure is:

• Meine Schwester | pflanzt | Tulpen ins Beet hinter dem Haus

German main clauses usually put the finite verb in the second position, not necessarily the second word, but the second slot.

Yes. German is flexible as long as the finite verb stays in second position in the main clause.

For example:

• Ins Beet hinter dem Haus pflanzt meine Schwester Tulpen, weil dort genug Sonne ist.

This is grammatical, but it puts more emphasis on the location.

Notice that once Ins Beet hinter dem Haus takes the first position, the verb pflanzt must still stay in second position, and the subject meine Schwester moves after it.

Because ist belongs to the clause weil dort genug Sonne ist, and its subject is genug Sonne, not Tulpen.

So the subordinate clause is about the sun/sunlight, not about the tulips.

• genug Sonne ist = there is enough sun

That is why the verb is singular: ist agrees with Sonne, which is singular.

It is a subordinate clause, so it has its own subject and verb:

• genug Sonne / understood expletive structure in English translation
• ist

But it depends on the main clause because weil means because and introduces a reason.

So it is grammatically a clause, but not usually a complete standalone sentence in this form.

The dictionary form is pflanzen, meaning to plant.

Here, pflanzt is:

• 3rd person singular
• present tense

So:

• ich pflanze
• du pflanzt
• er/sie/es pflanzt

Since the subject is Meine Schwester = she, pflanzt is the correct form.