Sjekk såbrettet selv når parsellhagen er tom.

In this sentence, selv når is most naturally understood together as even when.

So the structure is:

• selv når = even when
• parsellhagen er tom = the subordinate clause after it

That is important because selv on its own can also mean yourself, itself, or even, depending on context. But when it comes right before når, learners should strongly consider the combined meaning even when.

Sjekk is the imperative form of å sjekke.

That means it is a command, like:

• Sjekk! = Check!

In Norwegian, the imperative often looks like the verb stem. The subject is usually not stated, so the sentence is understood as directed to you.

Because Norwegian normally writes compound nouns as one word.

Here:

• så = sowing / seed-sowing
• brett = tray

So såbrett is a compound noun meaning something like seed tray or sowing tray.

Then såbrettet is the definite singular form: the seed tray.

This is very typical in Norwegian. English often separates or hyphenates things that Norwegian joins into one word.

The ending -et marks the definite singular of a neuter noun.

The base noun is:

• et såbrett = a seed tray

Definite form:

• såbrettet = the seed tray

So instead of using a separate word like the, Norwegian often adds the definiteness to the end of the noun.

For the same reason: it is the definite singular form, but this time of a common-gender noun.

• en parsellhage = an allotment garden / plot garden
• parsellhagen = the allotment garden

So:

• -en is common-gender definite singular
• -et is neuter definite singular

A parsellhage is an allotment garden, community garden, or a garden area divided into small plots that different people use.

The exact English translation can vary by country and context, but the core idea is a garden made up of separate plots.

Når usually means when. In some contexts it can also feel like whenever.

Here, because of selv når, the meaning is even when.

This is different from hvis, which means if.

Compare:

• når = when
• hvis = if

English sometimes uses when and if more loosely than Norwegian learners expect, so this is a useful distinction to notice.

Because tom agrees with the noun it describes.

Here, the subject is parsellhagen, and hage is a common-gender singular noun, so the adjective is:

• tom

Compare:

• parsellhagen er tom = common gender singular
• huset er tomt = neuter singular
• hagene er tomme = plural

So tomt would be used with a neuter singular noun, not with parsellhagen.

Yes. Norwegian allows that.

You could say:

• Selv når parsellhagen er tom, sjekk såbrettet.

That keeps the same basic meaning, but changes the emphasis a bit. Putting the clause first makes the even when... part more prominent.

The original version is also natural because Norwegian often places time or condition clauses after the main command.