A gyökér hosszú, ezért átültetjük a palántát.

A is the Hungarian definite article, meaning the.

So:

• a gyökér = the root
• a palántát = the seedling (as a direct object)

Hungarian has two forms of the definite article:

• a before consonant sounds
• az before vowel sounds

For example:

• a gyökér
• az alma

In Hungarian, the verb to be is often left out in the present tense, third person, when the sentence links a subject to a noun or adjective.

So:

• A gyökér hosszú literally looks like The root long
• but it means The root is long

This is completely normal Hungarian.

Compare:

• A gyökér hosszú. = The root is long.
• A gyökér hosszú volt. = The root was long.
• A gyökér hosszú lesz. = The root will be long.

In the past and future, the verb appears.

Because Hungarian adjectives do not work like adjectives in many Indo-European languages.

A few important points:

• Hungarian has no grammatical gender
• Predicative adjectives usually stay in a basic form
• So hosszú stays hosszú

That means:

• A gyökér hosszú. = The root is long.
• A levelek hosszúak. = The leaves are long.

In the plural, the adjective can take a plural marker in this kind of sentence, but there is still no gender agreement.

Ezért means therefore, so, for this reason, or that’s why.

It connects the first idea to the result:

• A gyökér hosszú, ezért átültetjük a palántát.
• The root is long, so we transplant the seedling.

It is a very common connector in Hungarian.

This is a very common question.

• mert = because
• ezért = therefore / so / for this reason

So:

• Átültetjük a palántát, mert a gyökér hosszú.
  = We transplant the seedling because the root is long.

• A gyökér hosszú, ezért átültetjük a palántát.
  = The root is long, therefore we transplant the seedling.

They express the same logical relationship, but from different directions:

• mert introduces the reason
• ezért introduces the result

Átültetjük means we transplant it or we are transplanting it, depending on context.

It can be broken down like this:

• át- = a verbal prefix, here suggesting moving something over / re-
• ültet = plant or cause to sit/place into the ground
• -jük = we with a definite object

So the whole form means something like:

• we transplant it
• in this sentence, it = the seedling

Because Hungarian verbs have two main conjugation patterns:

• indefinite conjugation
• definite conjugation

Here the object is definite:

• a palántát = the seedling

So Hungarian uses the definite verb form:

• átültetjük = we transplant it / the seedling

Compare:

• Átültetünk egy palántát. = We transplant a seedling.
  Here the object is indefinite, so the verb is different.

This is one of the most important features of Hungarian grammar.

Because palántát is the accusative form, used for the direct object of the verb.

• basic form: palánta = seedling
• direct object: palántát = seedling as the thing being transplanted

The suffix is -t, which often marks the direct object in Hungarian.

Also notice this change:

• palánta + t → palántát

The final a becomes long á before the suffix. This is very common with nouns ending in a or e.

Compare:

• kutya → kutyát
• körte → körtét

Not completely. Hungarian word order is more flexible than English word order, and it often reflects emphasis rather than strict grammatical roles.

This sentence has a natural, neutral order:

• A gyökér hosszú, ezért átültetjük a palántát.

But Hungarian can move things around for focus or contrast.

For example, if you want to emphasize the seedling, you might get a different structure.

So the sentence is not fixed the way English often is, but this version sounds very normal and straightforward.

In a neutral statement, Hungarian verbal prefixes usually stay attached to the verb:

• átültetjük

But if something is strongly focused, or if the sentence is negative, the prefix often separates.

For example:

• Nem ültetjük át a palántát. = We are not transplanting the seedling.
• A palántát ültetjük át. = It is the seedling that we transplant.

So in your sentence, the attached form átültetjük shows a neutral statement with no special focus before the verb.

Yes, it is present tense in Hungarian.

But Hungarian present tense can often cover meanings that English expresses with:

• simple present
• present progressive
• near future

So depending on context, átültetjük a palántát could feel like:

• we transplant the seedling
• we are transplanting the seedling
• we’ll transplant the seedling

In this sentence, the idea is something like:

• The root is long, so we transplant / will transplant the seedling.

Hungarian often lets context do the extra work instead of marking that distinction very explicitly.