CSLB General Building (B) — All Questions

A soil that drains very quickly, warms fast, and holds little water is MOST likely which texture?

• a.Clay
• b.Silt
• c.Sandy soil✓
• d.Peat

Sandy soils have large particles with large pore spaces, so water drains through rapidly and little is retained. They warm quickly in spring but dry out fast and need more frequent irrigation. Adding organic matter improves their water and nutrient holding capacity.

Most landscape and turf plants grow best in soil with a pH in which range?

• a.About 6.0 to 7.0 (slightly acidic to neutral)✓
• b.About 3.0 to 4.0
• c.About 9.0 to 10.0
• d.Exactly 8.5

A slightly acidic to neutral pH of roughly 6.0 to 7.0 keeps most nutrients available for uptake by common landscape plants and turf. Extremely acidic or alkaline soils lock up nutrients even when they are present. Acid-loving plants like azaleas prefer the lower end of this range.

To lower the pH of an alkaline soil, which amendment is commonly used?

• a.Agricultural lime
• b.Wood ash
• c.Gypsum for pH change
• d.Elemental sulfur✓

Elemental sulfur is oxidized by soil bacteria into sulfuric acid, gradually lowering soil pH over weeks to months. Lime and wood ash raise pH, and gypsum changes soil structure and adds calcium without significantly changing pH. Sulfur is the standard choice to acidify alkaline soils.

In a fertilizer labeled 16-6-8, the three numbers represent the percentage of which nutrients in order?

• a.Nitrogen, potassium, phosphorus
• b.Nitrogen, phosphorus, potassium✓
• c.Phosphorus, nitrogen, potassium
• d.Potassium, phosphorus, nitrogen

The three-number N-P-K label always lists nitrogen first, phosphorus (as P2O5) second, and potassium (as K2O) third. So 16-6-8 is 16 percent nitrogen, 6 percent phosphorus, and 8 percent potassium by weight. Nitrogen drives leafy green growth, phosphorus supports roots and flowers, and potassium aids overall vigor.

A 50-pound bag of 20-0-10 fertilizer contains how many pounds of actual nitrogen?

• a.10 pounds✓
• b.20 pounds
• c.5 pounds
• d.1 pound

Actual nitrogen equals the bag weight times the nitrogen percentage, so 50 pounds times 0.20 equals 10 pounds of nitrogen. Landscapers use this calculation to apply the correct pounds of nitrogen per 1,000 square feet. Knowing actual nutrient content prevents over- or under-application.

Applying a 3-inch layer of organic mulch around plants primarily provides what benefits?

• a.Raises soil pH sharply
• b.Eliminates all irrigation needs
• c.Conserves moisture, moderates soil temperature, and suppresses weeds✓
• d.Increases soil compaction

A layer of organic mulch reduces evaporation, keeps soil temperatures more stable, and blocks light that weed seeds need to germinate. As it decomposes it also adds organic matter to the soil. Mulch is one of the most cost-effective water-saving practices in landscaping.

When planting a container-grown shrub, the top of the root ball should be placed at what level relative to the surrounding soil?

• a.6 inches below grade
• b.12 inches below grade
• c.Buried under 4 inches of soil over the crown
• d.At or slightly above the surrounding grade✓

The top of the root ball should sit at or slightly above finished grade so the crown does not sit in water and settle too deeply. Planting too deep suffocates roots and can rot the crown or trunk. Slightly high planting allows for minor settling while keeping the crown dry.

Gypsum is added to certain clay soils primarily to accomplish what?

• a.Lower soil pH significantly
• b.Improve structure and displace sodium in sodic soils✓
• c.Add large amounts of nitrogen
• d.Kill weed seeds

Gypsum, calcium sulfate, supplies calcium that replaces sodium in sodic clay soils, improving aggregation and water penetration. It changes soil structure and drainage without appreciably altering pH. It is not a fertilizer and does not add nitrogen.

A newly planted tree needs staking. What is the correct staking practice?

• a.Allow some trunk movement and remove stakes after the tree establishes, usually within a year✓
• b.Tie the trunk rigidly for at least five years
• c.Drive one stake straight through the root ball
• d.Wrap wire tightly around the bark

Stakes should support the tree while allowing slight trunk movement, which encourages a stronger trunk and root system. Ties should be loose and use a broad, soft material, and stakes are typically removed after about one growing season. Rigid staking and bare wire damage the tree and create a weak, dependent trunk.

Which practice BEST improves drainage in a heavy clay planting bed?

• a.Compact the soil before planting
• b.Add fine sand only in small amounts
• c.Incorporate organic matter such as compost and improve grading✓
• d.Line the bottom of the bed with plastic sheeting

Blending compost and other organic matter into clay improves aggregation, creating larger pore spaces that let water move through. Combined with grading that directs excess water away, this relieves waterlogging. A small amount of sand can actually make clay worse by forming a concrete-like mix, and plastic traps water.

Proper plant spacing at installation should be based on what?

• a.The size of the nursery container only
• b.Fitting as many plants as possible
• c.The current size of the plant
• d.The mature size and spread of the plant✓

Plants should be spaced according to their expected mature width so they fill in without overcrowding. Spacing based on current small size leads to crowding, poor air circulation, and disease as plants grow. Good spacing reduces long-term maintenance and pruning.

A soil amendment high in nitrogen but low in decomposition, like fresh wood chips tilled into soil, can cause what short-term problem?

• a.Excess nitrogen burning plants
• b.Temporary nitrogen deficiency (nitrogen drawdown)✓
• c.A large rise in pH
• d.Immediate salt toxicity

When high-carbon materials like fresh wood chips are mixed into soil, microbes decomposing them consume available nitrogen, temporarily starving plants of it. This nitrogen drawdown causes yellowing until decomposition slows. Using wood chips as surface mulch instead of tilling them in avoids the problem.

Cool-season turfgrasses such as tall fescue grow most actively in which conditions?

• a.Cooler spring and fall temperatures✓
• b.The hottest summer weeks
• c.Deep winter freezes only
• d.Complete shade year round

Cool-season grasses like tall fescue peak in growth during the cooler temperatures of spring and fall and slow down in summer heat. Warm-season grasses such as Bermuda are the opposite, thriving in summer. Choosing the right type for the climate reduces water and maintenance needs.

When establishing turf from seed, keeping the seedbed consistently moist is important because what?

• a.Seeds germinate better when completely dry
• b.Water is needed only after sprouts appear
• c.Germinating seeds and shallow roots dry out and die quickly✓
• d.Moisture prevents any weed growth

Germinating seeds and their tiny first roots sit near the surface and die rapidly if the seedbed dries out. Light, frequent watering keeps the top layer moist until seedlings establish deeper roots. Once established, watering shifts to deeper and less frequent cycles.

Rough grading followed by finish grading before planting is done primarily to accomplish what?

• a.Increase soil compaction for planting
• b.Remove all topsoil from the site
• c.Create low spots that hold water
• d.Establish proper surface drainage and a smooth planting surface✓

Grading shapes the soil surface so water drains away from structures and toward intended outlets, and finish grading creates a smooth, even bed for planting or turf. Poor grading causes ponding, erosion, and drainage complaints. Positive slope away from buildings is a core goal.

Compost is added to soil primarily to do what?

• a.Raise pH to strongly alkaline levels
• b.Improve soil structure, add organic matter, and support microbial life✓
• c.Serve as the sole source of all nutrients permanently
• d.Compact the soil

Compost improves soil structure, increases water and nutrient holding capacity, and feeds beneficial soil microorganisms. While it adds some nutrients, its main value is as an organic amendment that improves overall soil health. It benefits both sandy and clay soils.

Which plant selection strategy BEST supports water-efficient landscaping in California?

• a.Choose climate-appropriate, drought-tolerant plants grouped by water needs (hydrozoning)✓
• b.Plant only high-water tropical species
• c.Mix high- and low-water plants on one valve
• d.Select plants at random from the nursery

Selecting drought-tolerant, climate-appropriate plants and grouping them by similar water needs, called hydrozoning, lets each irrigation zone be scheduled efficiently. Mixing high- and low-water plants on one valve forces overwatering of the low-water plants. Hydrozoning is a core MWELO efficiency practice.

A soil test reports very low phosphorus. Which fertilizer analysis would BEST correct it?

• a.21-0-0
• b.0-0-60
• c.0-45-0✓
• d.46-0-0

The middle number of the N-P-K label is phosphorus, so 0-45-0 supplies a high level of phosphorus and nothing else. 21-0-0 and 46-0-0 supply only nitrogen, and 0-0-60 supplies only potassium. Matching the deficient nutrient to the fertilizer analysis avoids waste.

Balled-and-burlapped (B&B) trees should have synthetic burlap and wire baskets handled how at planting?

• a.Left fully intact around the root ball forever
• b.Removed only after two years
• c.Never touched
• d.At least loosened and folded down, with synthetic (non-biodegradable) materials removed from the top of the ball✓

Natural burlap decomposes, but synthetic burlap and twine do not and can girdle roots, so they should be removed or at least peeled back from the top of the root ball. Wire baskets are cut and folded down after the tree is set. This lets roots grow outward into the surrounding soil.

Slow-release (controlled-release) fertilizers are advantageous because they do what?

• a.Release all nutrients within one day
• b.Release nutrients gradually, reducing burn risk and leaching✓
• c.Contain no nitrogen
• d.Only work below freezing

Controlled-release fertilizers meter nutrients out over weeks or months, lowering the risk of fertilizer burn and reducing nutrient leaching into groundwater. This gives steadier plant growth and fewer applications. They are especially useful for sandy soils where quick-release nutrients leach fast.

The planting hole for a balled tree should generally be dug how wide relative to the root ball?

• a.Two to three times the width of the root ball, no deeper than the ball✓
• b.Exactly the same width and twice as deep
• c.Half the width of the root ball
• d.Ten times the width and very deep

A hole two to three times as wide as the root ball loosens surrounding soil so new roots spread outward easily, while keeping depth equal to the ball prevents settling and deep planting. Digging deeper than the ball causes the tree to sink and the crown to sit too low. Wide and shallow is the standard rule.

Salt buildup in soil from irrigation water or fertilizer is BEST managed by what practice?

• a.Adding more fertilizer
• b.Reducing all watering to zero
• c.Leaching with deep irrigation to move salts below the root zone✓
• d.Compacting the soil surface

Applying a deep, thorough irrigation, called leaching, dissolves accumulated salts and carries them downward below the root zone where they no longer harm plants. This requires soil with adequate drainage. Adding more fertilizer would worsen the salt problem.