Hvis sommeren er varm nok, får vi en god høst af både tomater og græskar.

Sommeren is the definite form, meaning the summer.

In Danish, the seasons are often used in the definite form when talking about a specific season in a particular year or situation:

• sommeren = the summer
• vinteren = the winter

So Hvis sommeren er varm nok is literally If the summer is warm enough.

If you said Hvis en sommer er varm nok, that would sound more like If a summer is warm enough in a more general, less specific sense.

This is because of the Danish V2 rule in main clauses.

When something other than the subject comes first in a main clause, the finite verb must come second. Here, the sentence begins with the subordinate clause:

• Hvis sommeren er varm nok

After that, the main clause starts, and the verb comes before the subject:

• får vi en god høst

So:

• Hvis sommeren er varm nok, får vi ...

not

• Hvis sommeren er varm nok, vi får ...

This is very common in Danish word order.

Danish often uses the present tense for future meaning, especially in sentences about conditions, plans, or expected results.

So:

• Hvis sommeren er varm nok, får vi ...

means something like:

• If the summer is warm enough, we will get ...

English often uses present tense in the if-clause too, but Danish also commonly keeps the main clause in the present where English might prefer will.

You could use a future-style form in some contexts, but the present tense is very natural here.

Here nok means enough.

In Danish, nok usually comes after the adjective it modifies:

• varm nok = warm enough
• stor nok = big enough
• god nok = good enough

So varm nok is the normal word order.
You would not usually say nok varm in this meaning.

Høst is a common-gender noun, so it takes en in the singular:

• en høst = a harvest

So:

• en god høst = a good harvest

The adjective god stays in its basic en-word form here because høst is singular and common gender.

If the noun were neuter, the adjective form might change:

• et godt år = a good year

But here it is:

• en god høst

This part means of both tomatoes and pumpkins.

The structure is:

• af = of
• både ... og ... = both ... and ...

So:

• en god høst af både tomater og græskar

literally means:

• a good harvest of both tomatoes and pumpkins

The word både goes before the first item, and og connects the second:

• både tomater og græskar = both tomatoes and pumpkins

Because they are being used in a general, category-like sense.

In en god høst af både tomater og græskar, the speaker means a harvest consisting of tomatoes and pumpkins in general, not specific already-known tomatoes or pumpkins.

That is why Danish uses the bare plural forms:

• tomater
• græskar

Compare:

• en høst af tomater = a harvest of tomatoes
• de tomater = the tomatoes

Here, no definite article is needed.

Here græskar is plural in meaning: pumpkins.

This can be confusing because græskar has the same form in singular indefinite and plural indefinite:

• et græskar = a pumpkin
• græskar = pumpkins

So in this sentence, tomater og græskar means:

• tomatoes and pumpkins

The context makes it clear that græskar is plural here.

Because Hvis sommeren er varm nok is a subordinate clause, and the comma marks the boundary before the main clause:

• Hvis sommeren er varm nok, får vi en god høst ...

In Danish, it is normal to separate clauses with a comma like this. The comma helps show where the if-clause ends and the main statement begins.

Yes, you could, but it changes the nuance slightly.

• er varm nok = is warm enough
• bliver varm nok = becomes / gets warm enough

So:

• Hvis sommeren er varm nok focuses on the condition being true
• Hvis sommeren bliver varm nok focuses more on the summer reaching that level of warmth

Both are possible, but er varm nok is very natural in this kind of sentence.

Because høst is a common-gender noun, and singular common-gender nouns take the basic adjective form:

• en god høst

If the noun were neuter, the adjective would usually take -t:

• et godt resultat

So the form of the adjective depends on the gender and number of the noun it describes. Here:

• høst = common gender
• therefore god is correct

It is normal, natural Danish.

Nothing in it sounds especially formal or old-fashioned. It is the kind of sentence you could easily see or hear in everyday speech, in writing, or in something like gardening or farming context.

The only thing that may feel slightly more written than spoken is en god høst, but it is still completely natural.