Η γλάστρα θέλει νερό, της ρίχνω λίγο τώρα.

In Greek, θέλω very often means not just want, but also need, depending on context.

So:

• Η γλάστρα θέλει νερό
  literally: The pot wants water
  natural meaning: The plant/pot needs water

This is a very common Greek way to talk about things that require something:

• Το φαγητό θέλει αλάτι = The food needs salt
• Το αυτοκίνητο θέλει βενζίνη = The car needs petrol/gas

So even though the literal meaning is want, the natural English translation is often need.

Literally, γλάστρα means flowerpot / plant pot. But in everyday Greek it can also refer loosely to the potted plant as a whole.

So in a sentence like:

• Η γλάστρα θέλει νερό

a speaker usually means:

• The plant in the pot needs water
• or more loosely, The pot plant needs water

This is similar to how English sometimes says The plant needs water, even if technically you are watering the soil in the pot.

Because Greek often leaves out the article with mass nouns when speaking in a general, indefinite way.

Here, νερό means water in general, not the water.

Compare:

• θέλει νερό = needs water
• θέλει το νερό = needs the water / wants the water
  which sounds much more specific

This is similar to English:

• The plant needs water
• not usually The plant needs the water

Της is a weak pronoun referring back to η γλάστρα.

Here it means:

• to it
• or more naturally in English, it

So:

• της ρίχνω λίγο τώρα

means:

• I’m pouring a little to it now
• natural English: I’m giving it a little now / I’m pouring a little water into it now

Because γλάστρα is feminine, the pronoun is της.

This is a very common point for learners.

In Modern Greek, the old dative case no longer exists as a normal noun case. Its job is mostly taken over by:

• σε + accusative for full nouns
• genitive clitic pronouns for weak object pronouns like μου, σου, του, της, μας, σας, τους

So:

• ρίχνω λίγο νερό στη γλάστρα = I pour a little water into the pot
• της ρίχνω λίγο = I pour it a little

Even though της is technically genitive in form, in sentences like this it functions like an indirect object: to her / to it.

Because Greek often leaves out a noun when it is obvious from context.

The first clause already says:

• Η γλάστρα θέλει νερό = The pot needs water

So in the second clause:

• της ρίχνω λίγο τώρα

λίγο means a little, and νερό is understood.

In full, it could be:

• της ρίχνω λίγο νερό τώρα

But Greek naturally omits the noun if it is already clear.

Yes, ρίχνω often means throw, drop, or cast. But it has several everyday meanings, and with liquids it commonly means:

• pour
• put on
• add
• sometimes splash

So here:

• της ρίχνω λίγο τώρα

means something like:

• I’m pouring a little into it now
• I’m giving it a little water now

This is very natural Greek.

Other examples:

• Ρίχνω νερό στο ποτήρι = I pour water into the glass
• Ρίχνω ζάχαρη στον καφέ = I put sugar in the coffee

Because λίγο here is being used in a neutral, adverb-like/quantity way meaning:

• a little
• a small amount

It does not have to agree with γλάστρα. It refers to the omitted noun νερό, which is neuter:

• το νερό
• λίγο νερό

So the full idea is:

• της ρίχνω λίγο (νερό) τώρα

That is why λίγο is neuter singular.

Because Greek is a pro-drop language: subject pronouns are often omitted when the verb ending already shows the subject.

Here:

• ρίχνω = I pour

So εγώ is not necessary.

Greek usually includes εγώ only for emphasis or contrast:

• Εγώ της ρίχνω λίγο τώρα = I’m the one giving it a little now

Without emphasis, just ρίχνω is the normal choice.

In Greek, weak object pronouns like μου, σου, του, της, μας, σας, τους usually come before a finite verb.

So:

• της ρίχνω
• του λέω
• μου δίνει

This is the normal placement.

With an imperative, the pronoun usually comes after:

• Ρίξ’ της λίγο νερό! = Pour it a little water! / Give it a little water!

So in your sentence, της ρίχνω is exactly the expected word order.

Yes, absolutely. That is a very natural full version.

Compare:

• της ρίχνω λίγο τώρα = I’m pouring it a little now
• της ρίχνω λίγο νερό τώρα = I’m pouring it a little water now

The second version is more explicit. The shorter version sounds natural because νερό was already mentioned.

Τώρα means now.

It tells you that the action is happening at this moment:

• της ρίχνω λίγο τώρα = I’m giving it a little now

It can also add a slight practical tone, like:

• it needs water, I’ll give it some now

Greek often uses the present tense this way for something happening immediately.

Because in informal, natural Greek, two closely connected clauses are often placed side by side with a comma.

Here the logic is:

• Η γλάστρα θέλει νερό = The plant needs water
• της ρίχνω λίγο τώρα = I’m giving it a little now

So the comma creates a smooth conversational flow:

• The plant needs water, I’m giving it a little now.

You could also rephrase it with a conjunction, but the comma version sounds very natural in speech and informal writing.

Yes, Greek word order is fairly flexible, although some positions are more natural than others.

Possible variations include:

• Της ρίχνω λίγο τώρα
• Τώρα της ρίχνω λίγο
• Λίγο της ρίχνω τώρα
  though this one gives extra emphasis to λίγο

The most neutral version is the one you have. Greek changes word order mostly for emphasis, rhythm, or focus, not because the basic meaning changes a lot.