Часник і кріп дуже свіжі.

Because часник і кріп is a compound subject: two things joined by і (and). In Ukrainian, that makes the description plural.

So:

• Часник дуже свіжий. = The garlic is very fresh.
• Кріп дуже свіжий. = The dill is very fresh.
• Часник і кріп дуже свіжі. = The garlic and dill are very fresh.

Even though each noun is singular by itself, together they take the plural adjective свіжі.

In present-tense Ukrainian, the verb to be is usually omitted in sentences like this.

So Ukrainian often says literally:

• Часник і кріп дуже свіжі.
• word-for-word: Garlic and dill very fresh.

But in natural English, that becomes Garlic and dill are very fresh.

You normally do not add є here in a simple sentence like this.

They are in the nominative case, because they are the subject of the sentence.

More specifically:

• часник = nominative singular
• кріп = nominative singular
• свіжі = nominative plural, agreeing with the whole compound subject

So each noun stays singular, but the predicate adjective becomes plural because the subject is two items together.

Дуже means very.

It usually goes right before the adjective or adverb it modifies:

• дуже свіжі = very fresh
• дуже добрий = very good
• дуже швидко = very quickly

So Часник і кріп дуже свіжі is the normal word order for Garlic and dill are very fresh.

The dictionary form is свіжий, meaning fresh.

Some basic forms are:

• свіжий — masculine singular
• свіжа — feminine singular
• свіже — neuter singular
• свіжі — plural

In this sentence, the plural form свіжі is used because часник і кріп refers to two things.

It can mean either, depending on context.

Ukrainian has no articles like a or the, so the sentence itself does not tell you that directly. Context decides.

So this could be translated as:

• Garlic and dill are very fresh.
• The garlic and dill are very fresh.

If you were talking about produce at a market, English might naturally use the. If you were making a general statement about ingredients, English might leave it out.

Yes. Ukrainian word order is more flexible than English word order.

The sentence as given:

• Часник і кріп дуже свіжі.

is a neutral, natural way to say it.

Other orders are possible, but they change the emphasis:

• Дуже свіжі часник і кріп.
  This emphasizes very fresh more strongly.

• Часник і кріп свіжі.
  Same structure, just without дуже.

So the original version is a good standard pattern to learn.

Yes, Ukrainian has a few ways to say and.

• і = the most neutral, basic choice
• й = a euphonic variant of і, used when it sounds smoother
• та = also means and, often a bit more stylistic or formal depending on context

In this sentence, і is the most natural standard choice:

• Часник і кріп

The choice between і and й is usually about sound, not meaning.

A rough English-friendly approximation is:

chas-NYK ee kreep DOO-zhe SVEE-zhi

Stress:

• часни́к
• кріп
• ду́же
• сві́жі

A few sound notes:

• ч sounds like ch in church
• і sounds like ee in see
• ж sounds like the s in measure
• и in часник has no exact English equivalent; it is not the same as і

So свіжі sounds approximately like SVEE-zhi, not like English swiji.

You would use the singular form that matches the noun.

For these two nouns individually:

• Часник дуже свіжий.
• Кріп дуже свіжий.

Both часник and кріп are masculine singular nouns, so they take свіжий in the singular.

When you put them together with і, the adjective changes to plural:

• Часник і кріп дуже свіжі.