Cu cât udăm, cu atât tulpina devine mai mare.

This is a very common Romanian pattern meaning the more ... the more ... or sometimes the ...er ..., the ...er ....

So:

• Cu cât udăm = The more we water
• cu atât tulpina devine mai mare = the bigger the stem becomes

It is a correlative structure: the first part sets up a change in degree, and the second part shows the corresponding result.

A few similar examples:

• Cu cât înveți mai mult, cu atât știi mai multe.
  The more you study, the more you know.

• Cu cât e mai târziu, cu atât sunt mai obosit.
  The later it is, the more tired I am.

Because they work as a pair in this construction.

• cât = how much / how far / to what extent
• atât = that much / so much / to that extent

In cu cât ... cu atât ..., Romanian is literally doing something like:

• by how much ..., by that much ...

So the sentence is structurally close to:

• By how much we water, by that much the stem becomes bigger

That sounds unnatural in English, so we translate it as:

• The more we water, the bigger the stem becomes

Udăm is the 1st person plural present tense of a uda (to water).

So:

• eu ud = I water
• tu uzi = you water
• el/ea udă = he/she waters
• noi udăm = we water
• voi udați = you (plural) water
• ei/ele udă = they water

In the sentence, udăm means we water.

Romanian usually does not need the subject pronoun, because the verb ending already shows the person. So noi udăm and udăm both mean we water, but udăm is more natural unless you want emphasis.

Romanian often leaves out the object if it is obvious from context.

So udăm can mean:

• we water
• we water it
• we do the watering

depending on the situation.

In a sentence about a plant, a learner might expect something like:

• Cu cât o udăm, ... = The more we water it, ...

That is also possible if you want to make the object explicit. But Romanian often sounds perfectly natural without it when everyone already knows what is being watered.

Tulpina means the stem (or sometimes the stalk, depending on context).

The basic noun is:

• tulpină = stem

The form tulpina is the definite form, meaning:

• the stem

Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the.

So:

• tulpină = a stem / stem
• tulpina = the stem

This is very normal in Romanian:

• floare = flower

• floarea = the flower

• frunză = leaf
• frunza = the leaf

Because mai mare is the comparative form: bigger / larger.

• mare = big
• mai mare = bigger

In the pattern cu cât ... cu atât ..., Romanian usually expresses a comparison in degree, so mai is very common.

Here:

• tulpina devine mare = the stem becomes big
• tulpina devine mai mare = the stem becomes bigger

The second one fits the idea of the more X, the more Y.

Devine comes from a deveni, meaning to become.

So:

• tulpina devine mai mare = the stem becomes bigger

This is correct and natural. It focuses on a change of state.

Romanian could also use other verbs depending on nuance. For example:

• tulpina crește = the stem grows
• tulpina se face mai mare = the stem gets bigger

A rough comparison:

• devine mai mare = becomes bigger
• crește = grows
• se face mai mare = gets bigger

So devine is a good choice if you want to emphasize the result or change.

Romanian word order is fairly flexible, but this order is straightforward and natural.

The sentence is organized like this:

1. Cu cât udăm
2. cu atât tulpina devine mai mare

The second clause starts with cu atât, which links it clearly to the first clause. Then comes the subject:

• tulpina = the stem

Then the verb:

• devine = becomes

Then the comparative adjective:

• mai mare = bigger

You may see slightly different word orders in Romanian, especially for emphasis, but this version is simple and neutral.

Because the sentence expresses a general relationship or general truth, not a one-time event.

In English, we also often use the present in these kinds of statements:

• The more we water, the bigger the stem gets.

Romanian does the same:

• udăm = we water
• devine = becomes

Even though the idea is about a process over time, the present tense is the normal tense for general facts and repeated patterns.

Yes, the comma is normally used to separate the two parts of the cu cât ... cu atât ... structure.

So this is the standard punctuation:

• Cu cât udăm, cu atât tulpina devine mai mare.

The comma helps show that the first clause sets up the comparison and the second clause gives the result.

No, not literally. Tulpina specifically means the stem or stalk, so the sentence is talking about that part of the plant.

If Romanian wanted to say the plant, it would use:

• planta = the plant

So:

• Cu cât udăm, cu atât planta devine mai mare. = The more we water, the bigger the plant becomes.

Since the sentence says tulpina, it specifically refers to the stem.

Yes, that is possible, and it can sound even clearer in some contexts.

For example:

• Cu cât udăm, cu atât tulpina devine mai mare.
• Cu cât udăm mai mult, cu atât tulpina devine mai mare.

The second version makes the comparison more explicit:

• udăm mai mult = we water more

In many situations, learners may find cu cât ... mai mult, cu atât ... easier to recognize because it looks more like the English pattern the more ...

So both are possible, but the version with mai mult spells the comparison out more directly.