CSLB C-27 Landscaping ContractorSite Preparation and DrainageEasy
A landscape contractor is planning a new planting bed on a site with compacted soil and poor drainage. To improve the soil structure and aeration, which of the following organic amendments would be most effective when incorporated to a depth of 6-8 inches?
- AGravel
- BSand
- CCrushed concrete
- DComposted green waste
Show answer & explanationAnswer & explanation
Correct answer: D. Composted green waste
Composted green waste, such as composted yard trimmings or wood chips, is highly effective at improving soil structure, increasing aeration, and enhancing drainage in compacted soils. It adds organic matter that creates aggregates and improves porosity.
Why the other options are wrong
- A. Gravel does not contribute to soil structure improvement or add organic matter; it creates voids but doesn't bind soil particles effectively.
- B. Sand can worsen compaction in clay soils if not mixed in very large proportions, and does not add organic matter.
- C. Crushed concrete can alter soil pH and does not provide the organic matter or structural benefits needed for planting beds.
Organic Amendment for Soil Structure
Incorporating organic matter like composted green waste significantly improves soil structure, aeration, and drainage, especially in compacted or clay soils.
- Increases soil porosity and aggregation.
- Enhances water infiltration and retention.
- Provides nutrients and supports microbial life.
Memory trick: Organic matter is the 'glue' for better soil.