Poté co přesadím rostlinu, rosím ji.

Poté co means after or more literally after the point when.

In this sentence, Poté co přesadím rostlinu... means After I transplant the plant...

It is correct and natural, but it sounds a bit more formal or written. In everyday speech, many people would more often say potom co or sometimes use až, depending on the exact meaning.

So:

• poté co = correct, slightly more formal
• potom co = very common, more everyday
• až = often used for when/once, but not always interchangeable in every context

Because přesadím is a perfective verb form.

The verb pair is:

• přesazovat / přesazovat = imperfective
• přesadit = perfective

Přesadím is the present-tense form of the perfective verb přesadit, but in Czech, a perfective present usually refers to the future.

So přesadím here means:

• I will transplant
• or in context: after I transplant

If you used přesazuji / přesazuju, it would suggest something ongoing or habitual, like I am transplanting or I transplant regularly, which does not fit as well here.

That is a very common Czech pattern.

In Czech:

• imperfective present = usually true present / ongoing / habitual
• perfective present = usually future meaning

So přesadím literally looks like a present-tense form, but because it is perfective, it means a completed action in the future: I will transplant.

This is one of the biggest differences from English.

Examples:

• dělám = I do / I am doing
• udělám = I will do

So here:

• Poté co přesadím rostlinu... = After I transplant the plant...

Rosím is from the imperfective verb rosit, meaning to mist / to spray lightly.

In this sentence, the imperfective present most naturally gives a habitual or routine meaning:

• After I transplant a plant, I mist it.

That sounds like a general procedure or repeated action, not just one single future event.

So the sentence most naturally means something like:

• Whenever / after I transplant the plant, I mist it.

If you wanted to emphasize one single completed future action, Czech might use a different structure, depending on the exact nuance.

Most naturally, it sounds like a routine or general practice.

Why?

• přesadím = perfective, marking the transplanting as a completed step
• rosím = imperfective present, which often describes what one regularly does

So the sentence feels like:

• After I transplant a plant, I mist it.
• Once I’ve transplanted the plant, I mist it.

In the right context, it could refer to a future occasion, but on its own it sounds most like a habitual statement.

Because rostlinu is the accusative singular form, and the noun is the direct object of přesadím.

The base form is:

• rostlina = plant

But after a transitive verb like přesadit (to transplant), Czech uses the accusative:

• přesadím rostlinu = I transplant the plant

For this feminine noun, the ending changes like this:

• nominative: rostlina
• accusative: rostlinu

This is a very common pattern for feminine nouns ending in -a.

Because ji is the accusative form of she/it for a feminine noun, and here it means it referring back to rostlinu.

So:

• rosím ji = I mist it

The form jí is used for other cases, especially dative and sometimes genitive, not for the direct object here.

So in this sentence:

• rostlinu = the plant
• ji = it

Both are feminine because rostlina is a feminine noun.

Not exactly.

Rosit means to mist, to spray lightly, or to moisten with a fine spray, usually with water.

So it is more specific than English to water.

Compare:

• zalévat = to water a plant
• rosit = to mist / spray a plant

So if you use a spray bottle on the leaves, rosit is a very good verb.

Because the sentence begins with a subordinate clause:

• Poté co přesadím rostlinu = subordinate clause
• rosím ji = main clause

In Czech, a subordinate clause is normally separated by a comma from the main clause.

So:

• Poté co přesadím rostlinu, rosím ji.

The comma comes after the whole subordinate clause, not between poté and co.

Czech word order is flexible, but rosím ji is the neutral and natural order here.

The short pronoun ji is unstressed, so it usually does not stand at the very beginning of its clause unless there is a special reason.

So:

• rosím ji = neutral, normal
• ji rosím = possible only in marked contexts, but not the basic choice here

For a learner, rosím ji is the safest and most natural pattern.

Sometimes Czech can omit an object if the context makes it obvious, but here ji is very natural and expected.

• Poté co přesadím rostlinu, rosím ji. = complete and natural
• Poté co přesadím rostlinu, rosím. = sounds incomplete unless the context already strongly tells us what is being misted

So in a standalone sentence, keeping ji is the normal choice.