Quando começa a rega?

Both are possible in Portuguese.

• Quando começa a rega? is very natural, especially in questions.
• Quando a rega começa? is also correct, but it can sound a little more neutral or slightly more emphatic on a rega.

Unlike English, Portuguese does not need do/does in questions, and it often keeps normal verb forms without extra question words like does.

So Portuguese can ask a question simply by using:

• the question word quando
• normal verb conjugation
• intonation or a question mark

Começa is a conjugated verb form, while começar is the infinitive.

Here, the sentence needs a finite verb, because it is a complete question:

• começar = to start
• começa = starts / does start

The subject is a rega, which is third person singular, so the verb is also third person singular:

• a rega começa = the watering starts

That is why começa is used.

The subject is a rega.

Even though it comes after the verb, it is still the subject. Portuguese allows this kind of order much more easily than English, especially in questions.

So the structure is basically:

• Quando = question word
• começa = verb
• a rega = subject

English usually prefers When does the watering start?, but Portuguese can naturally put the verb before the subject here.

That a is the definite article, meaning the.

• a = the for singular feminine nouns
• rega is a feminine noun

So:

• a rega = the watering / the irrigation

Portuguese uses articles more often than English does, so seeing a here is very normal.

Yes, rega is feminine.

You can tell because it takes the feminine article a:

• a rega

Many nouns ending in -a are feminine, though not all. In this sentence, the article clearly shows the gender.

Because the noun is singular feminine, anything agreeing with it would also use feminine singular forms.

The cedilla in ç changes the sound of the letter c.

In Portuguese:

• c before a, o, or u normally sounds like k
• ç before a, o, or u sounds like s

So:

• comeca would suggest a k sound, which would be wrong
• começa gives the correct s sound

That is why começar and começa are written with ç.

A rough pronunciation for an English speaker is:

KWAN-doh koh-MEH-sah ah HEH-gah
or in some accents
KWAN-doh koh-MEH-sah ah HEH-ga

A few notes:

• qu in quando sounds like kw
• começa has the stress on me
• rega usually has a soft r sound in Brazilian Portuguese, often somewhat like an English h at the beginning of a syllable

Pronunciation varies by region, but this approximation will help.

Grammatically, começa is present tense, but Portuguese often uses the present to talk about scheduled or expected future events.

So depending on context, it can mean something like:

• When does the watering start?
• When is the watering starting?
• When will the watering start? in a scheduled sense

This is very common in both Portuguese and English.

Yes, rega is a real and understandable word in Brazil, especially in contexts involving plants, gardens, farming, or scheduled watering.

However, depending on the context:

• rega can sound like watering
• irrigação can sound more technical, like irrigation

So in everyday gardening, rega is perfectly natural. In agriculture, engineering, or official contexts, irrigação may be more common.

Yes. That is also correct.

• Quando começa a rega? = simpler, very natural
• Quando vai começar a rega? = more explicitly future-oriented

The second version uses ir + infinitive, a very common way to talk about the future in Brazilian Portuguese.

Both are normal, but Quando começa a rega? is shorter and often sounds very natural when asking about a schedule.

Yes. Rega can refer to the act or process of watering.

Depending on context, it may mean:

• the watering itself
• a watering period
• a watering schedule
• irrigation in a practical sense

So the exact nuance depends on the situation. If you are talking about a garden, farm, or automated system, a rega could refer to the time when watering begins.