В борщ я всегда добавляю укроп и петрушку.

Борщ is in the accusative singular here, because в can mean into when it shows movement or direction.

With добавлять (to add), Russian often expresses the destination with в + accusative:

• добавить соль в суп = to add salt to the soup
• добавить сахар в чай = to add sugar to the tea

So в борщ literally means into the borscht.

Also, борщ is a masculine inanimate noun, so its accusative singular looks the same as the nominative:

• nominative: борщ
• accusative: борщ

Yes, it could be left out.

Russian often drops subject pronouns when the verb already makes the subject clear. So both are possible:

• В борщ всегда добавляю укроп и петрушку.
• В борщ я всегда добавляю укроп и петрушку.

Including я can add a bit of emphasis or contrast, something like:

• As for me, I always add dill and parsley to borscht.

So я is not required for grammar, but it can help shape the tone.

Yes, that alternative is grammatical.

Russian word order is much freer than English word order. The sentence can be rearranged depending on what the speaker wants to emphasize.

Your sentence:

• В борщ я всегда добавляю укроп и петрушку.

This puts в борщ first, so the dish is the starting point or topic: As for borscht, I always add dill and parsley.

A more neutral order might be:

• Я всегда добавляю укроп и петрушку в борщ.

Another natural version is:

• Я всегда добавляю в борщ укроп и петрушку.

All of these are possible, but they sound slightly different in focus.

Добавляю is the imperfective form, and it is used here because the sentence describes a habit or something done regularly.

• я всегда добавляю = I always add
• я добавлю = I will add / I’ll add

Russian uses the imperfective present for repeated or habitual actions. Since всегда means always, the imperfective is exactly what you would expect.

So:

• Я всегда добавляю... = habitual action
• Я добавлю... = one future action

They are in the accusative case, because they are the direct objects of добавляю.

укроп

This is a masculine inanimate noun, so the accusative looks like the nominative:

• nominative: укроп
• accusative: укроп

петрушка → петрушку

This is a feminine noun, so the accusative singular changes:

• nominative: петрушка
• accusative: петрушку

That is why the two words look different even though both are direct objects.

Because feminine nouns ending in -а usually change to -у in the accusative singular when they are inanimate direct objects.

Examples:

• книга → книгу
• лампа → лампу
• петрушка → петрушку

So in this sentence:

• добавляю петрушку = I add parsley

This is one of the most common Russian case patterns.

Всегда means always and shows that this is a repeated, habitual action.

It works naturally with the imperfective verb:

• я всегда добавляю = I always add

It usually appears near the verb or before the part of the sentence it modifies. In this sentence, it fits very naturally between я and добавляю.

Russian does not have articles like English a/an and the.

So:

• борщ can mean borscht, the borscht, or even some borscht
• укроп can mean dill or the dill, depending on context

Russian relies on context, word order, and common sense instead of articles.

Not by itself in normal Russian.

When you have just two items, Russian normally uses и = and:

• укроп и петрушку

A comma is used in longer lists, usually before the final и:

• укроп, петрушку и сельдерей

So with only two ingredients, и is the standard choice.

Here it is more like into borscht.

Russian is expressing the idea of putting something into the soup:

• добавлять что-то в борщ
• добавлять что-то в суп
• добавлять что-то в чай

English often says to borscht / to the soup / to tea, but Russian commonly uses в + accusative in this kind of context.

So the Russian structure is closer to:

• I add dill and parsley into the borscht

even if natural English translation may prefer to the borscht.

Yes. Putting В борщ first highlights the dish as the topic.

It can sound a bit like:

• When it comes to borscht, I always add dill and parsley.
• Into borscht, I always add dill and parsley.

This fronting is common in Russian when the speaker wants to set the scene first and then say what happens in that context.

So the sentence is not just grammatical; it also has a natural discourse pattern:

1. topic: В борщ
2. subject/adverb/verb: я всегда добавляю
3. objects: укроп и петрушку