Ég sé að fræin fara að spíra núna.

They are two different words that just happen to look the same.

• The first að in Ég sé að ... is a conjunction meaning that. It introduces a whole clause: that the seeds are starting to sprout now.
• The second að in fara að spíra is the infinitive marker, like English to before a verb.

So:

• sé að = see that
• fara að spíra = begin to sprout

Because sjá is the infinitive, meaning to see. After ég, you need the present-tense form, and this verb is irregular:

• ég sé = I see
• þú sérð = you see
• hann/hún/það sér = he/she/it sees

So Ég sé is simply the correct present-tense form.

Fræin means the seeds, while fræ by itself means seed or seeds in an indefinite sense, depending on context.

Here:

• fræ = seed / seeds
• fræin = the seeds

The -in is the attached definite article, which is very common in Icelandic. Instead of using a separate word for the, Icelandic often adds it to the noun.

It is the subject of the clause að fræin fara að spíra núna, so it is in the nominative.

A useful thing to notice is that fræin is not the direct object of sé. The object of sé is actually the whole clause:

• Ég sé [að fræin fara að spíra núna]

So the structure is basically:

• I see [that the seeds are starting to sprout now]

Yes, fara usually means go, but in the expression fara að + infinitive, it often means begin/start to.

So:

• fara að spíra = start to sprout
• fara að rigna = start to rain
• fara að sofa = go to sleep / start sleeping

This is a very common Icelandic pattern. It does not usually feel as literal as English go to.

Because spíra is an infinitive here.

In fara að spíra, the only finite verb is fara. The verb after the second að stays in the infinitive:

• fræin fara = the seeds are starting
• að spíra = to sprout

So spíra does not change for person or number here.

Because the subject is plural: fræin = the seeds.

So the verb agrees in number with the subject:

• singular: fræið fer að spíra = the seed is starting to sprout
• plural: fræin fara að spíra = the seeds are starting to sprout

The noun is neuter, but the verb agreement here is about person and number, not gender.

Because after the conjunction að, Icelandic uses normal subordinate-clause word order.

So you get:

• að
  • subject + finite verb + rest

Here that gives:

• að fræin fara að spíra núna

This is different from the main clause, where Icelandic often follows verb-second patterns. In the subordinate clause, the subject-first order is completely normal.

Yes, it could move, but the final position is very natural and neutral.

• Ég sé að fræin fara að spíra núna = very normal
• Ég sé að fræin núna fara að spíra = possible in some contexts, but less neutral
• Núna sé ég að fræin fara að spíra = emphasizes now

So the sentence as written has a straightforward, natural flow.

Not always. It can mean either:

• literal visual seeing: I can see that ...
• noticing/realizing: I can tell that ...

In this sentence, both ideas fit well. The speaker may literally be looking at the seeds and noticing that they have begun to sprout.

Yes. Both can mean now.

• nú is often a bit shorter and can sound slightly more formal, compact, or stylistically neutral depending on context.
• núna is very common in everyday speech and often feels a bit more conversational or immediate.

So Ég sé að fræin fara að spíra nú would also be understandable and natural.