Which of the following is NOT a component of hydroseeding?

Hydroseeding is a planting process that involves a mixture of seed, fertilizer, mulch, and water. The main purpose of hydroseeding is to promote rapid growth of grass and plants in areas that may be challenging to seed using traditional methods.

Seed is a crucial component because it's the primary element that will grow into the desired vegetation. Fertilizer is also vital as it provides necessary nutrients to support plant growth. Water helps activate the seed and facilitates the germination process, ensuring that the mixture adheres to the area being seeded and maintains moisture for growth.

Concrete, however, is not a component of hydroseeding. It is not necessary or beneficial in the hydroseeding process, which focuses on establishing vegetation rather than creating a solid barrier or structure. The absence of concrete as a component confirms that it is not related to the hydroseeding method, making it the correct answer to the question.