Final answer:
The four prepositional phrases in the sentence are 'at the garden store', 'about their preferred environment', 'in the garden', and 'ahead of yourself'.
Step-by-step explanation:
The four prepositional phrases in the given sentence are:
- at the garden store
- about their preferred environment
- in the garden
- ahead of yourself
These phrases begin with prepositions (at, about, in, and ahead of) and provide additional information about the verbs or nouns in the sentence. Prepositional phrases act as adverbials, adjectives, or nouns in a sentence.