Meine Mutter kauft rote Paprika, weil die grünen Paprika ihr zu bitter sind.

My mother buys red bell peppers because the green bell peppers are too bitter for her.

Breakdown of Meine Mutter kauft rote Paprika, weil die grünen Paprika ihr zu bitter sind.

• sein: to be
• kaufen: to buy
• grün: green
• weil: because
• mein: my
• zu: too
• die Mutter: the mother
• ihr: her
• rot: red
• bitter: bitter
• die Paprika: the bell pepper

Questions & Answers about Meine Mutter kauft rote Paprika, weil die grünen Paprika ihr zu bitter sind.

Why is there a comma before weil?

In German, a subordinate clause introduced by weil is normally set off with a comma. So you write:

• ..., weil ...
  This is standard punctuation for subordinate clauses.

Why does the verb go to the end in weil die grünen Paprika ihr zu bitter sind?

Because weil introduces a subordinate clause, and in subordinate clauses the finite verb goes to the end.
Main clause: Meine Mutter kauft ... (verb in position 2)
Subordinate clause: ..., weil ... sind. (finite verb sind at the end)

Why is it sind and not ist?

Because die grünen Paprika is treated as plural here (multiple peppers), so the verb must be plural: sie sind.
If you meant one pepper, you’d more likely say: ..., weil die grüne Paprika ihr zu bitter ist.

Why is it die grünen Paprika—what is die doing here?

die is the definite article. In this sentence it’s plural and means the (as in “the green peppers”).
German uses:

• plural die = the (plural)
• singular feminine die = the (feminine singular)

Context decides which one it is; here the plural verb sind confirms it’s plural.

Why does the first part have no article: kauft rote Paprika (not kauft die rote Paprika)?

No article is common when talking about something in a general “shopping/ingredient” sense (similar to English “She buys red peppers”). It’s like an indefinite, general statement.
Using an article changes the meaning:

• kauft rote Paprika = she buys (some) red peppers in general
• kauft die rote Paprika = she buys the specific red pepper(s) we’re talking about
• kauft eine rote Paprika = she buys one red pepper

Why is it rote (with -e) but grünen (with -en)?

That’s adjective declension:

• rote Paprika has no article, so the adjective takes a “strong” ending. In plural accusative, that’s often -e: rote.
• die grünen Paprika has the definite article die (plural), so the adjective takes the “weak/mixed” ending -en: grünen.

So the endings differ because the presence of die changes the adjective ending.

Is Paprika singular or plural here? It looks the same.

Paprika is one of those nouns where the plural often looks identical to the singular in everyday use:

• singular: die Paprika
• plural: die Paprika (often) / sometimes die Paprikas (also possible, but less common in many contexts)

Here it’s plural because of die (plural reading) and the verb sind.

What does ihr mean here, and why is it not sie?

ihr here means to her (dative). It refers back to meine Mutter.
The pattern is: etwas ist jemandem zu + Adjektiv
= “something is too + adjective for someone” / “someone finds something too + adjective”

So:

• die grünen Paprika sind ihr zu bitter = the green peppers are too bitter for her / to her

sie would mean “she” (subject) or “her” (accusative), not the needed dative “to her.”

Why do we say ihr zu bitter sind—what is the grammar pattern?

This is a common construction:

• (Nominative thing) + sein + (Dative person) + zu + adjective

Examples:

• Der Kaffee ist mir zu heiß. (The coffee is too hot for me.)
• Die Schuhe sind ihm zu klein. (The shoes are too small for him.)

So here: die grünen Paprika (thing) + sind + ihr (dative person) + zu bitter.

Could the sentence start with the weil clause?

Yes. If the subordinate clause comes first, the main clause verb still stays in position 2, so you invert subject and verb in the main clause:

• Weil die grünen Paprika ihr zu bitter sind, kauft meine Mutter rote Paprika.

Why is Mutter capitalized, but rote/grünen are not?

German capitalizes all nouns: Mutter, Paprika.
Adjectives like rote and grünen are not capitalized unless they’re used as nouns (which they aren’t here).