What is a benefit of companion planting in home gardening?

Companion planting is the practice of growing certain plant species close together so that they benefit each other. Different plants interact in ways that can improve growth and reduce pest problems. For example, marigolds release chemicals from their roots that repel nematodes and certain insects, while basil planted near tomatoes can deter aphids and whiteflies. Some companion plants attract beneficial insects such as ladybirds and hoverflies, which feed on common garden pests.

Beyond pest control, companion planting can improve growth through nutrient sharing. Legumes such as beans fix atmospheric nitrogen in the soil, making it available to neighbouring plants. Tall crops can provide shade for heat-sensitive species, and ground-cover plants suppress weeds and retain soil moisture.

Improved growth and reduced pests is the correct answer because these are the direct, well-established benefits of companion planting. The other options describe negative outcomes - decreased crop yields, increased pest problems, and reduced soil quality - which are the opposite of what companion planting achieves when done correctly.