Od piątku do niedzieli nie robimy remontu, tylko odpoczywamy w ogrodzie.

Because after od (from) and do (to / until), Polish normally uses the genitive case.

So:

• piątek → piątku
• niedziela → niedzieli

That is why you get:

• od piątku = from Friday
• do niedzieli = until Sunday / through Sunday

This whole phrase means a time span: from Friday to Sunday.

Not exactly, though it is very close in many contexts.

• Od piątku do niedzieli literally means from Friday to Sunday
• W weekend means at/on the weekend

The Polish sentence is a bit more explicit: it includes Friday through Sunday, not just the idea of the weekend in a loose way.

This is a very common learner question. The short answer is: because of negation.

With the verb robić (to do / to carry out), a direct object is often in the accusative:

• robimy remont = we are doing a renovation

But when the sentence is negated, Polish very often changes that object to the genitive:

• nie robimy remontu = we are not doing a renovation

So:

• positive: robimy remont
• negative: nie robimy remontu

This is one of the classic Polish patterns learners need to get used to.

Remont usually means renovation, repair work, or home improvement work.

Depending on context, robić remont can mean things like:

• renovating an apartment
• doing construction or repair work in a house
• redecorating in a more serious, disruptive way

So it is broader than just a repair, and often suggests a bigger project.

In Polish, the present tense of an imperfective verb can be used for:

• what is happening now
• habitual actions
• scheduled or planned actions

So Od piątku do niedzieli nie robimy remontu, tylko odpoczywamy w ogrodzie can mean something like:

• From Friday to Sunday we aren’t doing renovation work; we’re just relaxing in the garden
• or From Friday to Sunday we won’t be doing renovation work; instead we’ll be relaxing in the garden

This kind of present-for-plans usage is very natural in Polish.

Because the sentence describes an activity over a period of time, not a single completed event.

• robić = imperfective to do
• odpoczywać = imperfective to rest / relax

Imperfective verbs are the normal choice for:

• ongoing actions
• repeated actions
• general activities over a stretch of time

Here the idea is not we will complete one rest or finish one renovation action, but rather what we are doing or not doing during that whole Friday-to-Sunday period.

Here tylko means but rather / instead.

After a negation, nie ..., tylko ... is a very common Polish pattern:

• nie X, tylko Y = not X, but Y / not X, rather Y

So:

• nie robimy remontu, tylko odpoczywamy
  = we’re not doing renovation work; instead, we’re relaxing

In other contexts, tylko can also mean only, but in this structure its contrastive meaning is the important one.

Because nie ..., tylko ... introduces a contrast between two parts of the sentence.

The comma helps separate:

• what is not happening
• from what is happening instead

So:

• nie robimy remontu, tylko odpoczywamy

This punctuation is standard in Polish.

Because after w meaning in, when you talk about location, Polish uses the locative case.

• ogród = garden
• w ogrodzie = in the garden

So this is the normal pattern for being somewhere:

• w domu = in the house
• w pracy = at work
• w ogrodzie = in the garden

W ogród would not work here, because that would suggest movement into something, and even then Polish would normally use a different form and structure.

Standard Polish uses w ogrodzie.

• w ogrodzie = in the garden

In some regional speech, you may hear na ogrodzie, but for learners, w ogrodzie is the correct and safest standard form.

Because the basic form is piątek (Friday).

When it changes case after od, the ending changes:

• piątek → piątku

The ą is part of the stem of the word, not something added just in this sentence.

Other weekday forms also change in their own ways, for example:

• poniedziałek → poniedziałku
• wtorek → wtorku
• piątek → piątku

Because niedziela is a feminine noun, and in the genitive singular it changes to niedzieli.

So:

• niedziela = Sunday
• do niedzieli = until Sunday

This is a normal feminine noun pattern in Polish. Compare:

• szkoła → do szkoły
• ulica → do ulicy
• niedziela → do niedzieli

The exact ending depends on the noun type.

No, it is not stated explicitly, but it is built into the verb forms.

• robimy = we do / we are doing
• odpoczywamy = we rest / we are resting

Polish often drops subject pronouns when they are clear from the verb ending. So there is no need to say my (we) unless you want extra emphasis.

Yes, you can, but it adds emphasis.

• Nie robimy remontu, tylko odpoczywamy w ogrodzie.
  = neutral
• My nie robimy remontu, tylko odpoczywamy w ogrodzie.
  = We’re not doing renovation work; we’re relaxing in the garden

Adding my can suggest contrast, emphasis, or correction.

The given word order is very natural, but Polish word order is fairly flexible.

The original version:

• Od piątku do niedzieli nie robimy remontu, tylko odpoczywamy w ogrodzie.

is neutral and clear.

You could also move things for emphasis, for example:

• Nie robimy remontu od piątku do niedzieli, tylko odpoczywamy w ogrodzie.
• W ogrodzie odpoczywamy od piątku do niedzieli.

But not every rearrangement sounds equally natural in every context. The original sentence is a good standard model.

Because in Polish, days of the week are normally written with a lowercase letter.

So:

• piątek
• niedziela

This is different from English, where Friday and Sunday are capitalized.

Yes. In time expressions, do often means until / up to.

So:

• od piątku do niedzieli is best understood as
  from Friday until Sunday
  or
  from Friday through Sunday

In natural English translation, from Friday to Sunday is often the smoothest wording.

Usually, odpoczywamy is the best choice here because it describes a continuous or repeated activity over those days.

A perfective form like odpoczniemy would mean we will have a rest / we will rest up, focusing more on the action as a whole or its completion. That does not fit this sentence as naturally.

So:

• odpoczywamy = we are relaxing / we relax
• odpoczniemy = we will rest / we will get some rest

For a Friday-to-Sunday activity description, the imperfective is more natural.

Yes, very much so. Robić remont is a common Polish collocation.

It is one of the standard ways to say:

• to do renovation work
• to renovate
• to be in the middle of renovation

So even though English might often prefer a verb like renovate, Polish very naturally uses robić + remont.