Frøposen er åpen.

Frøposen is a compound noun:

• frø = seed / seeds
• pose = bag or packet

So frøposen means the seed bag or the seed packet, depending on context. In everyday English, seed packet is often the most natural translation.

In Norwegian, the definite article the is often added to the end of the noun instead of being a separate word.

So:

• en pose = a bag / a packet
• posen = the bag / the packet

With the compound noun:

• en frøpose = a seed packet
• frøposen = the seed packet

So the -en is the definite ending meaning the.

Norwegian usually writes compound nouns as one word.

So:

• frø + pose → frøpose
• frøpose + -en → frøposen

This is very common in Norwegian. English often uses two words where Norwegian uses one compound word.

Because this sentence uses the verb er = is.

The structure is:

• Frøposen = subject
• er = is
• åpen = open

So åpen is not directly in front of the noun; it is describing the subject after the verb, just like in English:

• The seed packet is open

If you wanted the adjective directly before the noun, you would say something like:

• den åpne frøposen = the open seed packet

Norwegian adjectives change form depending on gender and number.

The noun pose is a common gender noun, and it is singular here. After er, the adjective takes the form that matches that noun:

• common gender singular: åpen
• neuter singular: åpent
• plural / some definite uses: åpne

So:

• Frøposen er åpen = correct, because frøpose is common gender singular.

Compare:

• Huset er åpent = The house is open
  because hus is neuter
• Dørene er åpne = The doors are open
  because it is plural

Pose is a common gender noun in Bokmål.

That is why you get:

• en pose = a bag / a packet
• posen = the bag / the packet

And in the sentence:

• Frøposen er åpen

the adjective uses the common gender singular form åpen.

In this compound, frø is best understood as the thing the packet contains: seed(s).

In Norwegian compounds, the first part often does not tell you clearly whether English should translate it as singular or plural. So frøpose can naturally be understood as:

• seed packet
• packet of seeds

Both ideas fit.

These are two vowels that English speakers often need to practice.

• ø in frø is a rounded front vowel. There is no exact English equivalent.
• å in åpen sounds roughly like the vowel in British law or more, but exact pronunciation depends on dialect.

A rough learner-friendly pronunciation might be:

• frø ≈ a rounded vowel something like fruh / frer but with lip-rounding
• åpen ≈ OH-pen

These are only approximations. The important thing is that ø and å are different sounds.

Yes, but it means something slightly different in structure.

• Frøposen er åpen = The seed packet is open
• Den åpne frøposen = The open seed packet

The first is a full sentence.
The second is just a noun phrase, not a complete sentence by itself.

So if you want to make it a full sentence, you could say:

• Den åpne frøposen ligger på bordet = The open seed packet is lying on the table

Yes. This is the normal word order for a simple statement:

• Subject + verb + complement

So:

• Frøposen = subject
• er = verb
• åpen = complement

This is very similar to English:

• The seed packet is open

Norwegian main clauses also follow the verb-second rule, so in more complex sentences the verb still tends to come early.

Yes. The word pose often means bag, but in context it can also be translated as packet, pouch, or similar words.

For gardening or shop context, seed packet is often the most natural English translation. In another context, seed bag could also work.

So the best English choice depends on what kind of container is meant.