CSLB Landscaping (C-27) Trade — All Questions

A zone of eight heads at 2.5 GPM each covers 1,200 square feet. What is its precipitation rate?

• a.About 0.8 inches per hour
• b.About 1.6 inches per hour✓
• c.About 1.2 inches per hour
• d.About 2.4 inches per hour

Total flow is 20 GPM, and 96.3 times 20 divided by 1,200 gives about 1.6 inches per hour. The 0.8 figure would come from half the flow or twice the area. The 1.2 figure does not follow from either input. The 2.4 figure would require roughly 30 GPM over the same area.

Rotary nozzles are substituted for standard spray nozzles on a sloped turf area. What schedule change follows?

• a.Shorter run times, because rotary nozzles apply water faster
• b.Longer run times, because rotary nozzles apply water more slowly✓
• c.Shorter run times, because the streams resist wind drift
• d.The same run times, because the nozzles thread onto the same bodies

Rotary nozzles put out a much lower precipitation rate than fixed sprays, so the same depth of water takes noticeably longer, which is exactly why they suit slopes and tight soils. They apply water more slowly rather than faster. Their wind resistance is real but does not shorten run time, and sharing a body does not mean sharing an application rate.

Heads along a walkway are throwing water across the concrete during every cycle. What is the first adjustment to make?

• a.Set the arc and radius so spray stops at the turf edge✓
• b.Lower the controller run time on that station by half
• c.Raise the heads on taller risers to clear the walkway
• d.Move the station to an early morning start time

Overspray onto pavement is a coverage problem, so adjusting each head to the correct arc and reducing radius so the pattern ends at the edge fixes the cause. Halving run time leaves the same overspray in every cycle. Taller risers throw water farther onto the walk. An earlier start time hides the waste rather than stopping it.

Why are irrigation cycles commonly scheduled for the hours before sunrise?

• a.Soil intake rate is naturally higher during darkness
• b.Municipal water pressure is lowest and gentler on the pipe
• c.Wind and evaporation losses are lowest at that time✓
• d.Foliage stays wet longer, which reduces plant stress

Early morning brings the calmest air and the lowest evaporative demand, so more of the applied water reaches the root zone. Pressure is typically higher rather than lower at night. Soil intake depends on texture and structure, not on time of day. Extended leaf wetness actually encourages foliar disease and is a reason to avoid evening watering.

A one-inch meter is rated at 50 GPM maximum. What flow should the designer plan the largest zone around?

• a.About 35 to 37 GPM, three quarters of the rating✓
• b.About 25 GPM, exactly half the rating
• c.About 60 GPM, since peak demand is brief
• d.The full 50 GPM, which the meter is rated to pass

Designers hold continuous irrigation demand near three quarters of the meter rating so friction loss through the meter stays reasonable and household demand can occur at the same time. Designing at the full rating leaves nothing for the building. Exceeding the rating is not acceptable at any duration. Half the rating is unnecessarily conservative and drives up zone count.

Where should a pressure gauge be attached to read the static pressure available to a proposed system?

• a.At an outside hose bibb with no water flowing on site✓
• b.At the controller location using a test manifold
• c.At the far end of the existing mainline while a zone runs
• d.At a spray head riser with the zone valve open

Static pressure is measured with no flow anywhere on the service, and an exterior hose bibb near the point of connection gives a clean reading. Reading at an open head or during a running zone gives dynamic pressure instead. A controller is an electrical enclosure with no water connection to test.

A hydraulic worksheet lists losses for the meter, the backflow assembly, the mainline, the valve, and the lateral. Why must the backflow assembly appear on it?

• a.It adds pressure downstream when the checks are clean
• b.It consumes a significant share of available pressure✓
• c.It sets the maximum velocity allowed in the mainline
• d.It reduces the flow the meter is able to deliver

A reduced pressure assembly typically eats about ten to twelve psi and even a double check takes several, so leaving it off the worksheet is a common reason zones run short of pressure. It does not change what the meter can deliver, it never adds pressure, and velocity limits come from pipe sizing rather than from the assembly.

A new commercial landscape exceeds the size threshold at which MWELO calls for a dedicated landscape water meter. What is the purpose of that meter?

• a.To provide a shutoff the fire department can operate in an emergency
• b.To allow the water purveyor to bill landscape water at a lower rate
• c.To keep landscape flow from reducing pressure inside the building
• d.To measure landscape use separately and compare it to the budget✓

Separating landscape flow from building flow is what makes it possible to compare actual use against the calculated water budget and to spot leaks. Rate structures vary by purveyor and are not the ordinance purpose. A meter is not a fire department connection, and metering does not by itself protect building pressure.CA MWELO (Title 23)

A mature oak sits in the middle of a new lawn area. What irrigation approach protects the tree?

• a.Put the tree on its own valve for deep, infrequent watering✓
• b.Include the tree in the turf zone and extend the run time
• c.Place a ring of spray heads at the trunk to soak the root crown
• d.Install a bubbler at the trunk and run it with every turf cycle

Established oaks decline under frequent shallow turf watering, especially near the trunk, so a separate valve allowing infrequent deep irrigation out toward the drip line is the protective choice. Sharing the turf schedule keeps the root crown wet. Heads or bubblers at the trunk concentrate water exactly where crown rot begins.

A bubbler is specified for a newly planted 24-inch box tree. What condition must accompany it?

• a.A check valve so the basin does not drain after shutoff
• b.A finer filter than the rest of the system requires
• c.A watering basin or root ball area that can hold the flow✓
• d.A pressure-compensating emitter installed on the same outlet

Bubblers discharge at a high rate in a small area, so a formed basin or a contained root ball area is required or the water simply runs off. A separate compensating emitter on the same outlet is redundant. A check valve addresses drainage in the lateral, not basin retention. Bubbler orifices are large and need no special filtration.

An older system is being retrofitted from spray heads to inline drip in the shrub beds. Which existing component most often has to be changed at the valve?

• a.The zone needs a larger solenoid to open at lower flow
• b.The zone needs a filter and a pressure regulator added✓
• c.The zone needs its common wire replaced with heavier gauge
• d.The zone needs the control valve relocated above the beds

Drip runs at low pressure and cannot tolerate particles, so a retrofit kit adding filtration and regulation at the valve is the standard change. Solenoids do not vary with flow. Wire gauge is unrelated to converting the piping. Relocating the valve uphill matters only for anti-siphon devices, not for a drip conversion.

How often should the ends of inline drip laterals be flushed on a maintained system?

• a.On a routine schedule, such as each season's start✓
• b.Once at installation, since the lines then stay sealed
• c.Only when emitter output visibly drops off
• d.Only after the filter has been replaced

Fines that pass the filter settle at the far end of every lateral, so routine flushing on a set schedule clears them before they plug emitters. Waiting for visible output loss means damage has already happened. Filter replacement does not remove what is already in the line, and a sealed system still accumulates sediment and biofilm over time.

A crew must locate a buried valve on a system with no as-built drawing. Which method is the appropriate first step?

• a.Energize the station and trace the valve wire with a locator✓
• b.Pressurize the zone and listen for flow at the meter
• c.Excavate along the mainline at ten-foot intervals
• d.Cut the lateral at the nearest head and follow it back

A wire tracer follows the energized valve wire directly to the solenoid, which is the least destructive way to find a buried valve. Random trenching along the mainline damages pipe and landscape. Listening at the meter confirms flow but gives no location. Cutting a lateral creates a repair without narrowing the search.

Which practice makes a valve manifold serviceable years after installation?

• a.Grouping all valves for the site into one continuous trench
• b.Solvent welding the valves directly to the mainline tee
• c.Setting the valve boxes two inches below finish grade
• d.Installing unions or slip fix couplings on each valve outlet✓

A union or repair coupling at each valve lets a technician remove one body without cutting and rebuilding the manifold. Welding valves solidly into the tee forces a cut-out for every repair. Boxes buried below grade cannot be found. Grouping all valves in one trench is a layout choice that does not make individual valves easier to replace.

A soil moisture sensor is added to an existing controller. How does it change operation?

• a.It calculates run times from local reference evapotranspiration data
• b.It adjusts nozzle pressure at each head to match soil conditions
• c.It allows a scheduled cycle only when soil moisture is below a set point✓
• d.It measures flow through the mainline and closes the master valve

A soil moisture sensor reports the condition of the root zone and permits or skips the programmed cycle based on a threshold. Using weather data to compute run times is what a weather-based controller does. Flow measurement and shutdown belong to a flow sensor and master valve. No sensor adjusts pressure at the heads.

An irrigation plan calls for check valves at heads on a slope and pressure regulation at every head. What performance problem do these two details address?

• a.Excess flow demand that exceeds the available meter capacity
• b.Poor uniformity caused by mismatched nozzle arcs
• c.Water waste from low-head drainage and from misting✓
• d.Root intrusion into laterals installed below grade

Check valves stop the lateral from draining out the lowest heads after each cycle, and head pressure regulation stops fogging at high pressure, so together they cut two common sources of waste. Arc mismatch is a nozzle selection issue. Meter capacity is addressed by splitting zones. Root intrusion is a subsurface drip concern handled by treated emitters.

A designer is deciding where to place the point of connection for a new system. Which location is generally preferred?

• a.At the farthest hose bibb so the run to the valves is shortest
• b.Downstream of the building pressure regulator inside the garage
• c.At the water heater cold inlet where a tee already exists
• d.On the service line ahead of the building, downstream of the meter✓

Connecting on the service between the meter and the building keeps irrigation demand from competing with fixtures inside and gives the backflow assembly a clean above-grade location. A connection past the house regulator inherits reduced pressure. A water heater inlet is a fixture supply, not a system connection. A distant hose bibb is undersized for zone flow.

Which statement about installing an irrigation system on a site served by recycled water is accurate?

• a.Recycled and potable lines may share a trench if both are Schedule 40
• b.Recycled water systems are exempt from backflow protection requirements
• c.Recycled water lines are marked with green tape and green valve boxes
• d.Recycled water piping is identified in purple and kept separate from potable✓

Recycled water piping, valve boxes, and identification tape are purple, and the system must be physically separated from potable piping with no cross-connections. Sharing a trench without required separation is not acceptable regardless of pipe class. Green identifies sewer, not recycled water. Recycled water is a health hazard and increases rather than removes backflow requirements.

A newly seeded lawn and an established shrub bed are on the same controller. How should the seeded area be scheduled during establishment?

• a.The same program as the shrubs, with a higher station multiplier
• b.Deep watering twice a week to encourage rooting downward
• c.Brief cycles several times a day to keep the seedbed damp✓
• d.One long cycle each morning to soak the full root zone

Seed germinates in the top fraction of an inch, which dries within hours, so short frequent cycles are correct until the stand fills in. A single long cycle leaves the surface dry by afternoon. Deep infrequent watering suits established plants but kills germinating seed. Matching the shrub program applies water at the wrong frequency entirely.

A residential system is set with a single program watering every zone every day for ten minutes. What is the main weakness of this schedule?

• a.The master valve cycles too often and will wear prematurely
• b.Zones will overlap and reduce pressure at the far heads
• c.Every hydrozone receives the same depth regardless of its need✓
• d.Total runtime exceeds what most controllers can store

A uniform daily schedule ignores the differences between turf, shrubs, and drip areas, so some plants are drowned while others stay dry, which is precisely what hydrozoning and separate programs exist to solve. Storage capacity is not a limit at this scale. Master valve cycling is normal wear. Controllers run stations sequentially, so overlap does not occur.

A rain shutoff device is installed but the system still runs during a storm. What should be checked first?

• a.Whether the sensor is wired into the circuit and not bypassed at the controller✓
• b.Whether the controller has enough stations for the sensor
• c.Whether the sensor is mounted below the roof eave for protection
• d.Whether the sensor is rated for the local reference evapotranspiration

Most controllers have a sensor bypass switch or a jumper that must be removed, and a sensor that is installed but bypassed does nothing, so the wiring and bypass setting are the first check. Station count is unrelated. Sensors are not rated to evapotranspiration values. Mounting under an eave is in fact wrong, because the sensor then never gets wet.

Turf on a narrow parkway strip between the curb and sidewalk shows chronic dry edges and stained concrete. What is the durable fix?

• a.Add two more spray heads and shorten the run time
• b.Convert the strip to subsurface drip with low water use plants✓
• c.Change the nozzles to a higher precipitation rate set
• d.Raise the heads and increase operating pressure at the valve

A narrow strip cannot be watered by overhead spray without overspray, which is why MWELO restricts it, and conversion to subsurface drip with appropriate plants solves both the dry edge and the staining. More heads and higher rates add more water to the pavement. Raising heads and pressure increases both drift and overspray.

Which situation calls for a separate zone rather than adding heads to an existing station?

• a.A lawn panel with a uniform slope of less than two percent
• b.A turf area whose heads are all the same nozzle family
• c.A shaded north-facing bed sharing a valve with full-sun turf✓
• d.A bed whose plants share the same mature size and habit

Shade and full sun produce very different water demand, so combining them on one valve guarantees that one area is mis-watered, and splitting the valve is the fix. Matching nozzle families, uniform plant habit, and a gentle uniform slope are all conditions that make a single shared station work well.

A contractor is asked to add a booster pump because static pressure at the meter is only 38 psi. What must be verified before installing it?

• a.That the pump is installed upstream of the water meter
• b.That the pump is wired to the same circuit as the controller
• c.That the purveyor permits pumping on the service and protection is adequate✓
• d.That the pump discharge exceeds the rating of the mainline pipe

Pumping on a potable service can pull down the main and creates backpressure, so purveyor rules and adequate backflow protection must be confirmed before anything is installed. Sharing a circuit with the controller is an electrical detail. Nothing may be installed upstream of the meter. A pump that exceeds the pipe rating would be a defect rather than a requirement.

At final walkthrough the owner asks for documentation of the new system. Which package is most useful for future maintenance?

• a.The soil report and the plant list from the landscape architect
• b.As-built drawings with valve locations plus the schedule and part list✓
• c.A copy of the hydraulic worksheet used during design
• d.The manufacturer catalog pages for the heads that were used

As-builts showing where valves and mainlines actually landed, together with the programmed schedule and the parts installed, are what a future technician needs to service the system. Catalog pages describe products without locating them. The soil report and plant list support planting decisions. The hydraulic worksheet documents design intent but not field conditions.

A soil report lists 45 percent sand, 35 percent silt, and 20 percent clay. What texture class is that, and what does it mean for irrigation?

• a.Clay loam, which requires frequent shallow irrigation cycles
• b.Silt loam, which holds the most water of any texture class
• c.Loam, which holds moderate moisture and drains at a moderate rate✓
• d.Sandy clay, which drains slowly and needs long soak periods

That mix falls in the loam class, the balanced texture that both retains usable moisture and drains at a workable rate. Sandy clay would need far more clay. Silt loam would need silt to dominate, and even then peats and organic soils hold more water. Clay loam is heavier than these percentages describe and is not watered by frequent shallow cycles.

Two beds are irrigated identically, one in sand and one in clay loam. Why does the sand bed need water more often?

• a.Sand transmits more water upward to the leaf canopy
• b.Sand loses more water to evaporation from the surface
• c.Sand has a higher permanent wilting point than clay loam
• d.Sand holds less available water per foot of soil depth✓

Large pores drain quickly and hold little water against gravity, so sand stores far less plant-available water per foot of depth and empties sooner. Surface evaporation is similar for both when mulched. Clay actually has the higher wilting point because it holds water too tightly to release. Soils do not transmit water to the canopy; roots and the plant do.

A percolation test in a proposed tree pit shows water standing in the hole 24 hours after filling. What does the installer conclude?

• a.The pit should be dug wider so more surface area is exposed
• b.The pit needs additional organic amendment mixed into the backfill
• c.Drainage is inadequate and the planting detail must be changed✓
• d.The soil is within the normal range for a clay site

Water standing a full day means the pit will hold the root ball in saturated soil, so the detail must change, whether by mounding, subdrainage, or moving the tree. Amending backfill in a poorly draining hole creates a bathtub that fills faster. Widening the hole does not give the water anywhere to go. A full day of standing water is a failure, not a normal clay result.

A landscape is failing in a heavy clay pad that was compacted by grading equipment. Which corrective measure addresses the root cause?

• a.Increasing irrigation frequency to keep the surface moist
• b.Ripping the compacted layer and incorporating organic matter✓
• c.Top-dressing with two inches of sand across the pad
• d.Applying a complete fertilizer at twice the label rate

Compaction destroys pore space, so roots and water cannot move, and breaking that layer and blending in organic matter restores structure. Extra fertilizer does not create pore space and can burn stressed roots. More frequent watering keeps a compacted soil saturated. A thin sand layer over clay creates a perched water table rather than drainage.

A soil test returns a pH of 8.1 on a site where azaleas are specified. What is the most practical response?

• a.Apply agricultural lime to buffer the soil before planting
• b.Plant as drawn and correct the pH with monthly acid rinses
• c.Revise the plant list toward species tolerant of alkaline soil✓
• d.Increase the phosphorus rate to offset the high pH

Sustained pH change on an alkaline California soil is slow, expensive, and prone to rebound, so matching the plants to the site is the durable answer. Lime raises pH and would make the problem worse. Extra phosphorus does not change pH and can tie up other nutrients. Monthly acid applications are a maintenance burden that rarely holds.

Which amendment is used to lower the pH of an alkaline landscape soil over time?

• a.Wood ash spread evenly and watered in
• b.Elemental sulfur, which soil bacteria convert to acid✓
• c.Dolomitic limestone worked into the top six inches
• d.Calcium carbonate blended with the backfill

Soil bacteria oxidize elemental sulfur into sulfuric acid, which is the standard way to move pH downward. Dolomitic limestone and calcium carbonate are liming materials that raise pH. Wood ash is strongly alkaline and raises pH as well, so three of these four choices move the soil in the wrong direction.

Newly emerging leaves on a citrus tree are yellow between green veins while older leaves stay dark green. What does this pattern suggest?

• a.Nitrogen deficiency, which appears first on new growth
• b.Phosphorus deficiency from cold soil temperatures
• c.Iron deficiency, common where soil pH is high✓
• d.Potassium deficiency caused by excess irrigation

Iron is immobile in the plant, so a shortage shows on the newest leaves as interveinal chlorosis, and it is common on alkaline California soils where iron is present but unavailable. Nitrogen is mobile and yellows the oldest leaves first and uniformly. Potassium shortage shows as marginal scorch on older leaves. Phosphorus shortage typically shows as dull purpling.

A 50-pound bag is labeled 15-5-10. How much actual nitrogen does the bag contain?

• a.1.5 pounds
• b.3.0 pounds
• c.7.5 pounds✓
• d.5.0 pounds

The first number is percent nitrogen by weight, so 15 percent of 50 pounds is 7.5 pounds. The 1.5-pound figure would come from a 3 percent product. Three pounds would come from a 6 percent product. Five pounds is the phosphate content of this bag expressed the same way, which is a common mix-up.

A specification calls for one pound of actual nitrogen per 1,000 square feet using a 20-0-10 fertilizer. How much product is applied per 1,000 square feet?

• a.10 pounds
• b.20 pounds
• c.2 pounds
• d.5 pounds✓

Dividing the pound of nitrogen wanted by the decimal fraction of nitrogen in the product gives 1 divided by 0.20, or 5 pounds of product. Ten pounds would deliver two pounds of nitrogen. Twenty pounds would deliver four pounds and risk burning. Two pounds delivers only four tenths of a pound and falls short of the specification.

An owner asks why the crew uses a controlled-release fertilizer on a slope above a creek instead of a soluble product.

• a.It contains more total nutrient per bag and covers more ground
• b.It changes soil pH less than soluble products do
• c.It releases gradually, lowering burn risk and leaching✓
• d.It costs less per pound of nitrogen than soluble fertilizer

A coated or slow-release product meters nutrient out over weeks, so less is available to wash off in a storm and less is present at any moment to burn roots, which matters directly above a waterway. Analysis per bag is usually lower rather than higher. Both types can affect pH depending on nitrogen source, and slow-release costs more per pound of nitrogen.

Fresh wood chips are tilled into a planting bed and the plants yellow within weeks. What happened?

• a.The chips held water and drowned the shallow feeder roots
• b.The chips raised soil pH beyond the range the plants tolerate
• c.The chips released natural herbicides that damaged the roots
• d.Microbes decomposing the chips tied up available soil nitrogen✓

High-carbon material incorporated into soil feeds a microbial bloom that immobilizes nitrogen while it decomposes, and the plants go hungry until the process finishes. Wood chips do not shift pH sharply. Allelopathic effects are limited to a few species and not the general case. Chips tilled in improve aeration rather than causing saturation.

How should the same wood chips be used so that nitrogen tie-up is not a problem?

• a.Left on the surface as mulch rather than incorporated✓
• b.Composted for two weeks and then tilled in at six inches
• c.Applied with a high-phosphorus starter fertilizer at planting
• d.Blended at no more than ten percent by volume into backfill

Tie-up happens where carbon and soil are mixed, so leaving chips on top confines the effect to a thin surface layer while the mulch still suppresses weeds and holds moisture. Two weeks is not enough composting. Even ten percent by volume still incorporates raw carbon. Phosphorus does not substitute for the nitrogen the microbes take.

What does MWELO require of a project regarding soil before the planting plan is finalized?

• a.A geotechnical report establishing the bearing capacity of the subgrade
• b.A record of the last three crops or land uses on the parcel
• c.A soil management report with testing and amendment recommendations✓
• d.A certified laboratory analysis of the irrigation water source

MWELO requires a soil management report so that amendment and mulching decisions are based on actual soil chemistry and texture rather than habit. Water quality analysis is useful but is not the required report. Bearing capacity belongs to structural design. Prior cropping history is not part of the ordinance.CA MWELO (Title 23)

MWELO sets a minimum mulch depth on exposed soil in planting areas. Which statement matches the requirement?

• a.Two inches, applied everywhere including turf areas
• b.Four inches, with the layer piled against trunks to hold moisture
• c.At least three inches, with turf and creeping groundcover excepted✓
• d.One inch, refreshed each time the landscape is fertilized

The ordinance calls for a minimum three-inch layer on exposed soil in planting areas and recognizes that turf, rooting groundcover, and direct-seeded areas cannot be mulched that way. Two inches falls short of the minimum. Four inches piled against trunks invites collar rot. One inch neither suppresses weeds nor conserves moisture.CA MWELO (Title 23)

Why must organic mulch be pulled back from the trunk of a newly planted tree?

• a.Mulch against the trunk prevents the root flare from taking up nitrogen
• b.Constant moisture against the bark encourages crown and collar rot✓
• c.Mulch against the trunk raises the soil pH in the root ball
• d.Mulch against the trunk attracts beneficial insects away from the canopy

Bark is not built to stay wet, and mulch heaped against it holds moisture that leads to collar rot and encourages rodents and adventitious roots. Insects are not the driving issue. The flare does not take up nitrogen. Mulch has little effect on pH within the root ball, and none of that would justify burying the trunk.

A five-gallon shrub comes out of the can with roots circling tightly around the outside of the root ball. What should the installer do?

• a.Plant it as is so the intact root ball is not disturbed
• b.Prune the top by a third to balance the restricted roots
• c.Score or tease the circling roots apart before backfilling✓
• d.Set it two inches deeper so the circling roots are covered

Circling roots continue to circle and eventually girdle the plant, so cutting or teasing them outward at planting is required. Planting as is preserves the defect. Pruning the top does not correct roots. Planting deeper buries the root crown, adds a second problem, and still leaves the circling roots in place.

What is the correct relationship between the root flare of a new tree and the surrounding finish grade?

• a.The flare is covered by four inches of amended backfill
• b.The flare is set level with the bottom of the watering basin
• c.The flare sits two inches below finish grade
• d.The flare sits at or slightly above finish grade✓

Planting with the flare at or slightly above grade keeps the trunk base dry and is the single most common difference between trees that establish and trees that decline. Setting the flare below grade or burying it under backfill traps moisture against the bark. A basin bottom sits below grade, so matching it would bury the flare as well.

Current practice for backfilling a tree pit in average native soil is which of the following?

• a.Backfill with imported topsoil to the full depth of the pit
• b.Backfill with native soil below and pure compost in the top foot
• c.Backfill with a fifty-fifty blend of native soil and nursery compost
• d.Backfill with the native soil that came out of the hole✓

Backfilling with native soil encourages roots to move out into the surrounding profile instead of staying in a rich pocket, and it avoids the texture interface that stalls water movement. Heavy compost blends, imported topsoil, and a compost cap all create that interface and can leave the tree rooted only inside the hole.

How wide should a planting hole be relative to the root ball, and why?

• a.Two to three times as wide, so loosened soil eases root spread✓
• b.Half again as wide, so amendment can be layered around the ball
• c.The same width, so the ball is held firmly on all sides
• d.Four times as wide, so a full drainage envelope can be created

A wide shallow hole gives new roots loosened soil to grow into laterally, which is where feeder roots actually go, and two to three times the ball width is the accepted range. A tight hole leaves compacted walls. Layering amendment around the ball creates a texture interface. Four times the width is unnecessary excavation with no added benefit.

A balled-and-burlapped tree arrives in a wire basket with synthetic burlap. What is the correct handling at planting?

• a.Leave the wrapping intact, since both materials break down in soil
• b.Set the tree, then cut away the upper basket and synthetic burlap✓
• c.Cut the burlap only at the top and leave the basket untouched
• d.Remove the basket entirely before the tree is set in the hole

Handling by the ball keeps it intact, so the tree is set first and the upper basket and all synthetic burlap are then cut away, since synthetic burlap never rots and wire can girdle roots. Leaving the wrapping intact assumes a decomposition that does not happen. Removing the basket before setting risks breaking the ball. Cutting burlap alone leaves the wire in place.

Two stakes are installed on a new tree. What describes correct staking?

• a.Ties pulled tight so the trunk cannot flex in any direction
• b.Ties placed just below the lowest branch and left for three seasons
• c.Stakes driven through the root ball for maximum holding power
• d.Ties placed low, allowing some trunk movement, removed within a year✓

Trunk movement builds taper and strength, so ties go low, stay loose, and come off once the tree anchors, usually inside a year. Tying high and leaving stakes for years produces a weak whippy trunk. Stakes driven through the ball damage roots. Rigid ties prevent the very movement that develops trunk strength.

In most of California, which season generally gives the best establishment for woody landscape plants?

• a.Late winter, when plants are fully dormant and shipping is easiest
• b.Midsummer, when nursery stock is fully hardened off
• c.Fall, when soil is still warm and winter rain follows✓
• d.Late spring, when soil has warmed and growth is rapid

Fall planting lets roots grow into warm soil while cool weather and coming rain reduce demand on the canopy, so plants enter their first summer established. Late spring gives only weeks before heat arrives. Midsummer planting stresses new roots hardest. Deep winter works for bare root stock but leaves cold soil and slow root activity for most container plants.

A shrub shows wilted foliage, and the soil around it is wet and smells sour. What is the most likely diagnosis?

• a.Transplant shock from root disturbance at installation
• b.Root rot from saturated soil starving roots of oxygen✓
• c.Drought stress that will resolve after one deep watering
• d.Salt burn from fertilizer applied at too high a rate

Roots need oxygen, and in saturated soil they suffocate and rot, which produces wilting that looks like drought while the soil is wet and smells anaerobic. Adding water makes it worse rather than better. Salt burn shows as marginal leaf scorch in dry soil. Transplant shock does not produce sour saturated soil.

A soil analysis reports a high electrical conductivity and a history of irrigation with hard well water. What management practice is indicated?

• a.Till the top foot to blend the salts through the profile
• b.Apply extra water periodically to leach salts downward✓
• c.Increase nitrogen so plants outgrow the salt injury
• d.Reduce irrigation volume so fewer salts arrive in the soil

Salts accumulate as water evaporates, and the only way to remove them is to move them downward with water applied beyond plant demand, provided the soil drains. Reducing irrigation concentrates salts further. Nitrogen fertilizer is itself a salt and adds to the load. Tilling redistributes salts without removing any of them.

Gypsum is recommended for a soil that has high sodium and poor structure. How does it work?

• a.It adds organic matter that binds soil particles together
• b.It increases the clay fraction so the soil holds more water
• c.It lowers soil pH directly by releasing free acid
• d.Calcium displaces sodium on clay particles so they can aggregate✓

Gypsum supplies calcium that exchanges with sodium on clay surfaces, letting particles flocculate into crumbs so water and air can move; the displaced sodium then leaches. It is neutral and does not lower pH the way sulfur does. It contains no organic matter and does not change the texture class of the soil.