בערב אני משקה את הפרחים, ובבוקר הוא משקה את הצמח הגדול.

The prefix ב־ means in / at.

In both of these time expressions, Hebrew is effectively saying:

• בערב = in the evening
• בבוקר = in the morning

What is happening is that ב־ combines with the definite article ה־ (the).

So, roughly:

• ב + ה + ערב → בערב
• ב + ה + בוקר → בבוקר

They look different because Hebrew handles this combination differently depending on the first letter of the noun:

• With בוקר, the article is absorbed and the next consonant can be doubled, giving בבוקר
• With ערב, the first letter is ע, a guttural letter, and gutturals do not take that doubling, so the form looks different: בערב

So even though the spellings are different, both are normal ways of saying a definite time phrase.

Here משקה is the present-tense form of the verb להשקות, which means to water or to give water to.

So:

• אני משקה את הפרחים = I water the flowers / I am watering the flowers
• הוא משקה את הצמח = he waters the plant / he is watering the plant

A useful thing to know: in unpointed Hebrew, משקה can also be a noun meaning drink / beverage, but here the sentence structure makes it clearly a verb.

Because Hebrew present tense usually marks gender and number, not person, the way English does.

So in the present tense, the same verb form can be used with different subjects:

• אני משקה = I water
• הוא משקה = he waters

Both use the same present form here.

This is different from English, where I water and he waters look different.

That is also one reason Hebrew often includes the subject pronoun in present-tense sentences: the verb by itself may not tell you who is doing the action.

את is the direct object marker. It appears before a definite direct object.

In this sentence:

• את הפרחים = the flowers
• את הצמח הגדול = the big plant

Important points:

• את does not mean with here
• It usually is not translated into English
• It tells you that the following noun phrase is the direct object of the verb

So:

• משקה את הפרחים = waters the flowers
• משקה את הצמח הגדול = waters the big plant

Because in Hebrew, adjectives usually come after the noun they describe.

So:

• הצמח הגדול = the big plant
  • literally: the plant the-big

Hebrew adjective order is different from English:

• English: the big plant
• Hebrew: the plant big

This is completely normal Hebrew word order.

Because when a noun is definite, its adjective must also be definite.

So:

• צמח גדול = a big plant
• הצמח הגדול = the big plant

This agreement is very important in Hebrew.

The adjective also agrees with the noun in:

• gender
• number
• definiteness

Here:

• צמח is masculine singular
• so the adjective is גדול (masculine singular)
• and because the noun is definite, the adjective becomes הגדול

A very useful contrast:

• הצמח הגדול = the big plant
• הצמח גדול = the plant is big

So the extra ה־ helps show that the adjective is part of the noun phrase, not the predicate of a sentence.

Hebrew often attaches small function words directly to the next word as prefixes.

ובבוקר contains several pieces:

• ו־ = and
• ב־ = in
• ה־ = the
• בוקר = morning

So the whole word means:

• ובבוקר = and in the morning

Hebrew packs these little words together instead of writing them separately.

It can mean either one, depending on context.

Hebrew present tense often covers both:

• a habitual meaning: waters
• a current ongoing meaning: is watering

In this sentence, because of the time expressions בערב and בבוקר, the most natural reading is a habitual or routine one:

• In the evening I water the flowers, and in the morning he waters the big plant.

But grammatically, the present form itself does not force only one of those English translations.

Yes. Hebrew can place time expressions at the beginning very naturally.

So:

• בערב אני משקה את הפרחים
• אני משקה את הפרחים בערב

Both are grammatical.

Starting with בערב and בבוקר gives the sentence a clear time frame right away, a bit like:

• In the evening, I water the flowers, and in the morning, he waters the big plant.

So this is a word-order choice, not a special tense rule.

Sometimes Hebrew leaves out subject pronouns, but in the present tense they are often useful, because the verb form does not clearly show person.

Here, keeping the pronouns helps make the contrast very clear:

• אני = I
• הוא = he

That contrast matters in this sentence, so using both pronouns is very natural.

Without them, the sentence would be much less clear, especially because משקה by itself does not tell you whether the subject is I, he, or someone else with the same gender/number pattern.