C27 License - C-27 Landscaping Contractor License Planting and Soil Management Questions and Answers — Questions and Answers
Question 1: A client has heavy clay soil and wants to plant a new tree. To ensure proper establishment and long-term health, what is the MOST appropriate backfilling technique?
- Amend the backfill generously with sand and organic compost to create a rich, loamy mixture.
- Backfill the planting hole using only the native clay soil that was originally excavated. (Correct answer)
- Dig the hole twice as deep as the root ball and fill the bottom half with gravel for drainage.
- Replace all the native soil with a pre-mixed planter soil from a nursery.
Correct answer: Backfill the planting hole using only the native clay soil that was originally excavated.
When planting in clay soil, it is best to use the native soil as backfill. Amending the soil in just the planting hole can create a 'bathtub effect,' where water collects in the amended soil and does not drain into the surrounding dense clay, potentially leading to root rot. The roots need to adapt and grow into the surrounding native soil for long-term stability and health.
Question 2: According to the California Model Water Efficient Landscape Ordinance (MWELO), when preparing a new landscape area of 1,000 square feet, what is the minimum amount of compost that should be incorporated into the soil?
- 1 cubic yard to a depth of 3 inches
- 2 cubic yards to a depth of 4 inches
- 4 cubic yards to a depth of 6 inches (Correct answer)
- 6 cubic yards to a depth of 8 inches
Correct answer: 4 cubic yards to a depth of 6 inches
The California Model Water Efficient Landscape Ordinance (MWELO) requires that for new landscape projects, compost shall be incorporated at a rate of at least four cubic yards per 1,000 square feet to a depth of six inches, unless contradicted by a soil test. This is to improve soil health, water retention, and reduce the need for irrigation.
Question 3: Which of the following is the PRIMARY reason for conducting a soil compaction test before beginning a hardscape installation?
- To determine the soil's pH and nutrient levels for future planting.
- To identify the presence of beneficial microorganisms.
- To ensure the soil has adequate organic matter content.
- To verify the soil's density and ability to support the structure without settling. (Correct answer)
Correct answer: To verify the soil's density and ability to support the structure without settling.
A soil compaction test is critical for determining if the soil has the necessary density and strength to provide a stable foundation for structures like patios, walkways, or retaining walls. Properly compacted soil minimizes the risk of settlement, shifting, or structural failure over time.
Question 4: When planting a container-grown shrub, the planting hole should be dug:
- To the exact same depth and width as the container.
- Slightly deeper than the root ball to allow for soil settling.
- Two to three times wider than the root ball, but no deeper than the root ball. (Correct answer)
- At least six inches deeper and wider than the root ball on all sides.
Correct answer: Two to three times wider than the root ball, but no deeper than the root ball.
The proper technique is to dig the planting hole two to three times wider than the diameter of the root ball, but only as deep as the root ball itself. Planting too deep is a common and serious error that can lead to root suffocation and girdling roots. A wider hole allows the roots to spread out into loosened soil, promoting faster establishment.
Question 5: A landscape plan for a residential property in California calls for a new lawn. To comply with the Model Water Efficient Landscape Ordinance (MWELO) prescriptive approach, what is the maximum percentage of the total landscape area that can be dedicated to turf?
- 50%
- 25% (Correct answer)
- 75%
- 10%
Correct answer: 25%
Under the prescriptive compliance approach of the California MWELO, the total turf area is not to exceed 25% of the entire landscape area for a residential project. This regulation is designed to limit high-water-use plantings and encourage water conservation.
Question 6: What is the primary purpose of applying a 3-inch layer of organic mulch to all exposed soil surfaces in a newly planted landscape bed?
- To provide a significant source of immediate nutrients to the plants.
- To prevent all insect activity in the garden bed.
- To retain soil moisture, suppress weeds, and regulate soil temperature. (Correct answer)
- To increase the soil's pH level for acid-loving plants.
Correct answer: To retain soil moisture, suppress weeds, and regulate soil temperature.
Applying a layer of mulch is a crucial practice for several reasons: it helps the soil retain moisture by reducing evaporation, suppresses the growth of weeds that compete for resources, and moderates soil temperature, protecting roots from extreme heat and cold. The California MWELO also requires a minimum 3-inch layer of mulch on all exposed soil surfaces in planting areas.
C27 License - C-27 Landscaping Contractor License Planting and Soil Management Questions and Answers
A client has heavy clay soil and wants to plant a new tree.
To ensure proper establishment and long-term health, what is the MOST appropriate backfilling technique?