Morgen ga ik naar de kapper, want mijn haar is te lang geworden.

Both are correct.

• Ik ga morgen naar de kapper = I’m going to the hairdresser tomorrow
• Morgen ga ik naar de kapper = Tomorrow I’m going to the hairdresser

The difference is mainly emphasis. When you put Morgen first, you highlight the time.

This also triggers a very important Dutch word order rule: in a main clause, the finite verb must be in the second position. So:

• Ik ga morgen ...
• Morgen ga ik ...

You cannot say:

• Morgen ik ga ... ❌

That is one of the most common mistakes for English speakers.

This is the verb-second rule (V2), which is very common in Dutch.

In a normal main clause:

• position 1 = one element (subject, time word, place word, etc.)
• position 2 = the finite verb

So in this sentence:

• Morgen = position 1
• ga = position 2
• ik = comes after the verb

This happens whenever something other than the subject comes first:

• Vandaag werk ik thuis
• In Amsterdam woont zij
• Na het eten lezen we

So Morgen ga ik is not unusual at all; it is standard Dutch grammar.

De kapper usually means the hairdresser or the barber/hairdresser, depending on context. In Dutch, kapper is often used more generally than English barber.

So:

• naar de kapper gaan = to go to the hairdresser / barber

It refers to going to the place or professional who cuts your hair.

Dutch often uses this expression the way English uses:

• I’m going to the hairdresser
• I’m going to get my hair cut

So naar de kapper is a very natural fixed expression.

In Dutch, this expression normally uses the article:

• naar de kapper
• naar de tandarts
• naar de dokter

This is similar to English expressions like to the dentist or to the doctor.

So naar de kapper is the standard idiomatic form.
Naar kapper without de sounds incomplete or non-standard in normal Dutch.

Yes, you could use omdat, but the grammar changes.

With want

Want means because, and it introduces a new main clause.
That means normal main-clause word order stays in place:

• Morgen ga ik naar de kapper, want mijn haar is te lang geworden.

Here, is stays before te lang geworden because this is a main clause.

With omdat

Omdat introduces a subordinate clause, so the verbs move to the end:

• Morgen ga ik naar de kapper, omdat mijn haar te lang is geworden.

Notice the difference:

• want mijn haar is te lang geworden
• omdat mijn haar te lang is geworden

Both are correct.
Want is often a bit more conversational and straightforward.
Omdat sounds slightly more tightly connected grammatically to the first clause.

Because after want, Dutch uses main clause word order, not subordinate clause word order.

So the finite verb stays in second position:

• mijn haar is te lang geworden

Structure:

• mijn haar = subject
• is = finite verb
• te lang geworden = rest of the predicate

If you used omdat, then the verb placement would change:

• omdat mijn haar te lang is geworden

That difference between want and omdat is very important in Dutch.

Te means too when used before an adjective or adverb.

So:

• te lang = too long
• te duur = too expensive
• te laat = too late
• te moeilijk = too difficult

In this sentence:

• mijn haar is te lang geworden = my hair has become too long

So te shows that the length has passed an acceptable limit.

Geworden is the past participle of worden, which means to become.

So:

• lang worden = to become long
• te lang geworden = become too long

In the sentence:

• mijn haar is te lang geworden

the idea is not just my hair is too long, but my hair has gotten too long / has become too long.

That adds a sense of change over time.

Compare:

• Mijn haar is te lang. = My hair is too long.
• Mijn haar is te lang geworden. = My hair has become too long / gotten too long.

The second version suggests it was acceptable before, but now it is not.

In Dutch, some verbs form the perfect tense with zijn instead of hebben.
Worden is one of them when it means to become.

So:

• mijn haar is lang geworden
• het is koud geworden
• hij is boos geworden

This is similar to how some other European languages use to be as the auxiliary with verbs of change or movement.

So:

• is geworden = correct
• heeft geworden = incorrect

In Dutch, haar usually refers to hair in general as a mass noun, like English hair.

• mijn haar = my hair

Haren means hairs, meaning individual strands.

So:

• Mijn haar is te lang = normal, natural
• Mijn haren zijn te lang = possible, but less natural here, and it focuses more on separate hairs

When talking about getting a haircut, Dutch normally uses haar, not haren.

Yes, absolutely. That is also completely correct.

Compare:

• Ik ga morgen naar de kapper = neutral statement
• Morgen ga ik naar de kapper = extra emphasis on tomorrow

Both mean the same basic thing. The choice depends on what you want to emphasize and what sounds natural in the conversation.

Yes. Ga is the present tense of gaan, but Dutch often uses the present tense to talk about the near future, just like English does.

• Morgen ga ik naar de kapper.
• Vanavond eet ik pasta.
• Volgende week vertrek ik naar België.

English does this too:

• Tomorrow I’m going to the hairdresser
• Tonight I’m eating pasta

So there is no special future tense required here.

Yes, but it would sound a bit different.

You could say:

• Morgen zal ik naar de kapper gaan

This is grammatical, but in everyday Dutch, the simple present is usually more natural for planned future events:

• Morgen ga ik naar de kapper

Using zullen can sound more formal, more deliberate, or sometimes less direct depending on context. For ordinary plans, Dutch usually prefers the present tense.

The original sentence is already natural. In speech, you might also hear slightly simpler versions such as:

• Morgen ga ik naar de kapper, want mijn haar is te lang.
• Morgen ga ik naar de kapper. Mijn haar is te lang geworden.

The full sentence with geworden is perfectly normal and clear.
If someone wants to sound a little more casual, they may drop geworden and just say:

• mijn haar is te lang

But the original version gives a nice sense that the hair has gradually grown too long.

A lot of useful Dutch grammar appears in this one sentence:

1. Time word first

   • Morgen can come first for emphasis.

2. Verb-second rule

   • Morgen ga ik ..., not Morgen ik ga ...

3. Fixed expression

   • naar de kapper gaan

4. Reason with want

   • want introduces a main clause

5. Main-clause word order after want

   • mijn haar is te lang geworden

6. te + adjective

   • te lang = too long

7. perfect tense with zijn

   • is geworden

8. mass noun

   • haar = hair in general, not individual hairs

It is a short sentence, but it contains several very common Dutch patterns.