Tekuté hnojivo používám při zálivce.

Because tekuté agrees with hnojivo in gender, number, and case.

• hnojivo is neuter singular
• so the adjective must also be neuter singular
• the neuter singular form of tekutý here is tekuté

So tekuté hnojivo means liquid fertilizer.

It is the direct object of používám, so it is in the accusative.

However, for many neuter singular inanimate nouns, the accusative looks exactly the same as the nominative. So:

• nominative: hnojivo
• accusative: hnojivo

That is why the form does not change.

Používám means I use or I am using, depending on context.

It is the 1st person singular present tense form of the imperfective verb používat.

The ending -ám tells you the subject is I, so Czech does not need a separate word for I unless you want emphasis.

Because Czech often omits subject pronouns when they are clear from the verb ending.

So:

• používám already means I use
• já používám would also be possible, but já would usually add emphasis or contrast

For example, Já používám tekuté hnojivo could mean I use liquid fertilizer (maybe unlike someone else).

Literally, it means something like during watering or in the course of watering.

• při = during, while, in the course of, at
• zálivce = watering in the locative singular

So the whole phrase means when watering or during watering.

Because the preposition při requires the locative case.

The basic dictionary form is:

• zálivka = watering, irrigation

But after při, it changes to the locative singular:

• při zálivce

So this is a normal case change caused by the preposition.

Zálivka is a noun meaning watering, the act of watering, or sometimes irrigation.

In gardening language, it often refers to the watering process or watering treatment. In this sentence, it means the time or activity of watering plants.

A close English translation would be:

• when watering
• during watering

Yes, absolutely.

Both are natural, but there is a slight difference in style:

• při zálivce = using a noun, a bit more compact, often sounds slightly more technical or matter-of-fact
• při zalévání = using a verbal noun, often feels a bit more like while watering

Both can work in everyday Czech.

Czech word order is flexible, and the first position often shows the topic or what the speaker wants to highlight first.

So Tekuté hnojivo používám při zálivce puts liquid fertilizer first, as the thing being discussed.

Other word orders are also possible, for example:

• Používám tekuté hnojivo při zálivce.
• Při zálivce používám tekuté hnojivo.

These all mean roughly the same thing, but the emphasis and flow are slightly different.

Usually it sounds like a habitual or general statement:

• I use liquid fertilizer when watering

That is because používám is present tense of an imperfective verb, which often describes repeated, usual, or ongoing actions.

So the sentence most naturally means this is what the speaker normally does, not just what they are doing once.

Not always. The best translation depends on context.

With this sentence, natural English could be:

• when watering
• during watering
• while watering

So při does not always correspond to one single English word. Here it expresses something happening in the course of another activity.

Because Czech has no articles.

So tekuté hnojivo can mean:

• liquid fertilizer
• a liquid fertilizer
• the liquid fertilizer

The exact meaning depends on context. In this sentence, English usually prefers the general sense liquid fertilizer with no article, but Czech itself does not mark that distinction with articles.