Hierdie plante groei beter in die skaduwee as in sterk sonlig.

Hierdie means this or these. In this sentence, it means these, because plante is plural.

• hierdie plante = these plants
• die plante = the plants
• daardie plante = those plants

So hierdie is a demonstrative word: it points out which plants you mean.

Because plante is the plural form of plant.

• plant = plant
• plante = plants

A lot of Afrikaans nouns form the plural with -e, although there are other plural patterns too. Here it is just a normal singular/plural change.

No. In Afrikaans, verbs usually do not change according to the subject in the present tense.

So you get:

• Ek groei
• Jy groei
• Hy groei
• Ons groei
• Hierdie plante groei

That is much simpler than English, where you have I grow but he grows.

Here beter means better, and it describes how they grow, not what the plants are like.

So it is working like an adverb in English:

• Hierdie plante groei beter = These plants grow better

It is not saying the plants are better plants. It is saying their growth is better under those conditions.

After a comparative word like beter, Afrikaans uses as to mean than.

• beter as = better than
• groter as = bigger than
• vinniger as = faster than

So:

• in die skaduwee as in sterk sonlig = in the shade than in strong sunlight

A useful contrast:

• so groot soos = as big as
• groter as = bigger than

Because both sides of the comparison are prepositional phrases:

• in die skaduwee
• in sterk sonlig

Afrikaans normally keeps the structure clear by repeating the preposition.

So the sentence literally compares:

• better in the shade
• than in strong sunlight

If you leave out the second in, the sentence sounds incomplete or unnatural.

Because the two expressions work a little differently.

• in die skaduwee is a very common, natural phrase meaning in the shade
• in sterk sonlig means in strong sunlight in a general sense

Skaduwee here is treated as a definite environment: the shade.
Sonlig is an uncountable noun, like sunlight, so it often appears without an article when you mean it generally.

You could sometimes say in die sterk sonlig, but that would sound more specific, like in the strong sunlight.

Because sterk is the normal form used here before the noun.

Afrikaans adjectives do sometimes change form in front of nouns, but not all adjectives do so in the same way in every context. In this phrase, sterk sonlig is the standard, natural wording.

So just learn this combination as:

• sterk sonlig = strong sunlight

Sonlig is a compound noun:

• son = sun
• lig = light
• sonlig = sunlight

Afrikaans uses compound nouns very often, just like Dutch and German. So instead of a two-word phrase, you often get one combined word.

This is a normal main clause, so the verb comes early in the sentence, in the usual second position pattern:

• Hierdie plante = first element
• groei = verb
• beter in die skaduwee as in sterk sonlig = the rest

So the structure is:

subject + verb + rest

You can move other parts to the front, but then the verb still stays in second position. For example:

• In die skaduwee groei hierdie plante beter as in sterk sonlig.

That is also correct, but the verb groei still comes right after the first element.

It most often means shade in contexts like this, especially when talking about sunlight and where plants grow best.

So:

• in die skaduwee = in the shade

In some contexts, it can also relate to shadow, but in this sentence the meaning is clearly shade, not a sharply defined shadow cast by one object.

Yes. That is a very close, natural translation.

Word by word, it is roughly:

• Hierdie = these
• plante = plants
• groei = grow
• beter = better
• in die skaduwee = in the shade
• as = than
• in sterk sonlig = in strong sunlight

So the Afrikaans sentence is quite straightforward once you know the comparison pattern beter ... as ....