Если не дать растению удобрение вовремя, листья начинают вянуть.

Because если не дать растению удобрение вовремя is an impersonal infinitive construction.

Literally, it is something like:

If not to give the plant fertilizer in time, the leaves start to wilt.

In natural English, we would usually supply a subject, such as if you don’t give the plant fertilizer in time. In Russian, the subject can be left unspecified when the meaning is general.

This kind of structure is common when Russian talks about:

• general truths
• instructions
• typical results
• cause-and-effect situations

So the sentence does not mean a specific person is being talked about. It means whenever the plant is not given fertilizer in time, this happens.

Растению is in the dative singular because it is the recipient of what is being given.

The verb дать means to give, and with this verb Russian normally uses:

• someone/something receiving = dative
• the thing being given = accusative

So here:

• растению = to the plant
• удобрение = fertilizer

You can think of the pattern as:

дать кому? что?
to give to whom? what?

So:

• растению answers кому?
• удобрение answers что?

Because удобрение is the direct object, not the recipient.

With дать, Russian usually works like this:

• кому? = the receiver → dative
• что? = the thing given → accusative

So in this sentence:

• растению = to the plant → dative
• удобрение = fertilizer → accusative

Since удобрение is a neuter noun, its nominative and accusative singular forms are the same, so it looks unchanged:

• nominative: удобрение
• accusative: удобрение

That is why it may seem harder to spot the case at first.

Дать is the perfective verb, while давать is imperfective.

Here, дать is used because the sentence refers to a completed act of giving fertilizer at the needed time. The idea is:

• if the plant is not given fertilizer at the necessary moment,
• then the leaves start to wilt.

Perfective is natural because the focus is on the result or failure of the act to happen, not on an ongoing process.

Compare:

• Если не дать растению удобрение вовремя...
  If the plant is not given fertilizer in time...

• Если не давать растению удобрение...
  If you do not give the plant fertilizer / if you never give fertilizer to the plant...

The second version sounds more like a repeated or ongoing lack of fertilizing, while the original sentence focuses on the needed act being missed.

Russian often uses the present tense for general truths and regular consequences, just like English can do.

So:

листья начинают вянуть
= the leaves begin to wilt

This does not necessarily mean it is happening right now in one specific situation. It expresses a general pattern:

• when this condition happens,
• this is the result.

This is similar to English sentences like:

• If you don’t water plants, they die.
• If you heat ice, it melts.

Russian very naturally uses the present tense in such statements.

Начинают is imperfective present, which fits a general, habitual, or typical result.

Using начнут would make it sound more like:

• a more concrete future consequence,
• tied to a specific situation.

So the difference is roughly:

• листья начинают вянуть
  the leaves begin to wilt / tend to begin wilting
  → general truth

• листья начнут вянуть
  the leaves will begin to wilt
  → specific future outcome

In this sentence, the speaker is stating a general fact, so начинают is the natural choice.

Because начинать commonly takes an infinitive, just like English to begin.

So:

• начинать / начать делать что-то
  to begin to do something

Here:

• начинают = begin
• вянуть = to wilt

Together:

листья начинают вянуть
= the leaves begin to wilt

This is a very common Russian pattern:

• начал говорить = began to speak
• начала плакать = began to cry
• начинают расти = begin to grow

Вовремя means on time, in time, or at the proper time.

In this sentence, it means the fertilizer must be given at the needed moment for the plant. If that does not happen, the leaves begin to wilt.

So:

не дать растению удобрение вовремя
= not give the plant fertilizer in time

A learner should notice that вовремя is an adverb, so it describes how/when the action is done.

It is different from:

• во время = during
• вовремя = on time / in time

For example:

• Он пришёл вовремя. = He arrived on time.
• Во время урока он молчал. = During the lesson he was quiet.

Because Russian has no articles.

English must choose between:

• a plant / the plant
• fertilizer / the fertilizer
• the leaves

Russian does not mark this with separate words. Instead, the meaning is understood from:

• context
• word order
• general meaning
• whether the statement is specific or general

So:

• растению can mean to a plant or to the plant
• удобрение can mean fertilizer or the fertilizer
• листья can mean leaves or the leaves

In this sentence, the overall meaning is general, so English often translates it with the plant and the leaves, but Russian itself does not explicitly mark that.

Because a single plant normally has multiple leaves.

So the structure is:

• растению = to the plant
• листья = the leaves

There is no mismatch here. Russian is simply saying that if the plant does not get fertilizer in time, its leaves start to wilt.

Also, листья is the nominative plural of лист in the sense of leaf.

Yes. Russian word order is relatively flexible, though the original sentence is very natural.

Original: Если не дать растению удобрение вовремя, листья начинают вянуть.

You could also encounter variations like:

• Если вовремя не дать растению удобрение, листья начинают вянуть.
• Листья начинают вянуть, если не дать растению удобрение вовремя.

The basic meaning stays the same, but the emphasis can shift slightly.

The original order is straightforward because it presents:

1. the condition first
2. then the result

That is a very common and clear pattern in Russian.

It can grammatically refer to a plant in general, even though the noun is singular.

Russian often uses the singular to talk about a whole class in a general way, especially in statements about how things work.

So this sentence can be understood as a general truth:

If a plant is not given fertilizer in time, its leaves begin to wilt.

This is similar to English sentences like:

• If a child doesn’t sleep enough, they get tired.
• A car needs fuel to run.

So even though растению is singular, the meaning is general, not necessarily one specific plant.