It is read:
うえきばち に ひりょう を いれる
In normal Japanese writing, you would usually write it without spaces:
植木鉢に肥料を入れる。
を marks the direct object — the thing that is being acted on.
Here, the thing being put into the pot is 肥料.
So:
A simple way to see it is:
This is a very common question.
So:
Because someone is actively putting the fertilizer in, 入れる is the correct verb here.
In this sentence, に is often translated as in or into, but it is not exactly the same as an English preposition.
Japanese particles do not match English prepositions one-to-one. Here, に marks the target location of the action. In natural English, that becomes in or into.
So it is fine to understand:
But it is better to think of に as a Japanese grammar marker, not as a word that always equals one English preposition.
Japanese normally puts the verb at the end of the sentence.
So the basic order here is:
This is normal Japanese sentence structure. English and Japanese word order are different, so it is best not to expect a direct word-for-word match.
Yes, to some extent.
Because the particles に and を show the roles of the nouns, Japanese word order is more flexible than English. For example, these can both work:
Both mean essentially the same thing. The difference is mostly one of focus or natural flow in context.
However, the verb 入れる will usually stay at the end.
The subject is omitted.
Japanese very often leaves out the subject when it is obvious from context. So this sentence could mean:
The exact subject is understood from the situation, not stated in the sentence itself.
入れる is in the dictionary form (plain non-past form).
This form can be used for several things depending on context, such as:
Related forms would be:
So this sentence is in a basic plain form often used in dictionaries, examples, and simple statements.
Yes, but adding は changes the nuance.
For example:
肥料は植木鉢に入れる。
As for the fertilizer, put it in the flowerpot.
植木鉢には肥料を入れる。
In the flowerpot, one puts fertilizer. / At least in the flowerpot, fertilizer is put in.
Here, は adds topic or sometimes contrast. The original sentence with に and を is more neutral and straightforward.
Usually, に is the natural choice here.
So:
植木鉢（うえきばち） means flowerpot or plant pot.
It is made of:
So together, 植木鉢 is the pot that a plant grows in.
Yes. It is a perfectly natural simple sentence.
Without context, it sounds a little like:
In real conversation, you might also hear polite or more contextual versions like:
But the original sentence is grammatically natural and very useful for learning.