Hvis tomaterne ser trætte ud, giver hun dem lidt gødning om aftenen.

Hvis means if and introduces a condition.

So:

• Hvis tomaterne ser trætte ud = If the tomatoes look tired
• giver hun dem lidt gødning om aftenen = she gives them a little fertilizer in the evening

This is a very common way to build conditional sentences in Danish.

In Danish, a subordinate clause is normally separated from the main clause with a comma.

Here:

• Hvis tomaterne ser trætte ud = subordinate clause
• giver hun dem lidt gødning om aftenen = main clause

So the comma is required in standard written Danish.

Tomaterne means the tomatoes, while tomater means just tomatoes in a general sense.

The ending -ne is the definite plural ending here:

• en tomat = a tomato
• tomater = tomatoes
• tomaterne = the tomatoes

So the sentence is talking about specific tomatoes, not tomatoes in general.

This is the Danish way to say look tired.

It is made up of:

• ser = see / looks
• ud = out
• trætte = tired

Together, se ... ud often means to look / appear.

Examples:

• Hun ser glad ud = She looks happy
• Det ser mærkeligt ud = It looks strange

So tomaterne ser trætte ud literally looks a bit like the tomatoes look tired out, but the natural meaning is simply the tomatoes look tired.

With se ud, the particle ud often comes after the adjective or description.

So Danish says:

• ser trætte ud
• ser glade ud
• ser mærkelig ud

This is normal word order with this expression. English learners often expect ser ud trætte, but that is not the usual structure here.

Because tomaterne is plural, the adjective must also be plural.

• træt = tired, singular/common form
• trætte = tired, plural and also definite contexts

Examples:

• Tomaten ser træt ud = The tomato looks tired
• Tomaterne ser trætte ud = The tomatoes look tired

So trætte agrees with plural tomaterne.

This is because Danish follows the verb-second rule in main clauses.

The sentence begins with a subordinate clause:

• Hvis tomaterne ser trætte ud

After that, the main clause starts, and the finite verb comes first in that main clause:

• giver hun dem lidt gødning om aftenen

So the order is:

• subordinate clause
• finite verb
• subject

This is different from English, where you would say she gives.

Compare:

• Hun giver dem lidt gødning = She gives them a little fertilizer
• Hvis ..., giver hun dem lidt gødning = If ..., she gives them a little fertilizer

Giver is the present tense of give.

The infinitive is:

• at give = to give

Present tense:

• jeg giver
• du giver
• hun giver

Danish verbs do not change for person the way English does, so the same present form is used with all subjects.

Dem means them and refers back to tomaterne.

So:

• giver hun dem lidt gødning = she gives them a little fertilizer

It is the object pronoun form, used when the tomatoes are receiving the action.

Lidt means a little / some.

So:

• gødning = fertilizer
• lidt gødning = a little fertilizer / some fertilizer

Because gødning is usually treated as an uncountable substance here, Danish often uses lidt when talking about a small amount.

Here it is being used as an uncountable noun, like water, soil, or fertilizer in English.

That is why Danish uses lidt rather than a plural form.

You would normally say:

• lidt gødning = some fertilizer

not something like en gødning in this meaning.

Om aftenen means in the evening or in the evenings, depending on context.

In this sentence it most naturally means in the evening, as a time when she does this.

Danish often uses om for times of day in this kind of general time expression:

• om morgenen = in the morning
• om dagen = during the day / in the daytime
• om aftenen = in the evening
• om natten = at night

By contrast, i aften means this evening / tonight, referring to a specific evening.

So:

• om aftenen = generally in the evening
• i aften = this evening, tonight

Not in this exact structure.

Because the sentence begins with the hvis-clause, the main clause must follow Danish verb-second order:

• Hvis tomaterne ser trætte ud, giver hun dem lidt gødning om aftenen.

If you started directly with the main clause, then you would get:

• Hun giver dem lidt gødning om aftenen, hvis tomaterne ser trætte ud.

Both are correct, but the word order changes depending on what comes first.

Most naturally, it sounds like a habitual or general action:

• whenever the tomatoes look tired, she gives them some fertilizer in the evening

Danish present tense often covers this kind of general truth, routine, or repeated behavior.

Without extra context, it does not strongly suggest just one single event.

A few common pitfalls are:

• Reading ser only as sees instead of looks
• Missing that se ... ud works together as look/appear
• Forgetting that tomaterne means the tomatoes
• Expecting English word order after the if-clause and wanting hun giver instead of giver hun
• Not recognizing om aftenen as a time expression meaning in the evening

So the main grammar points to notice are the expression ser ... ud, the definite plural -ne, and the verb-second word order in the main clause.