20 Turf Maintenance Practice Questions & Answers

1. 1. A crew maintains a Kentucky bluegrass lawn in a cool northern climate and is planning the season's nitrogen program. Which timing decision gives the stand the most benefit, and why?

   • A.Apply the largest nitrogen application in mid-summer, because heat stress is when the turf needs the most feeding.
   • B.Apply the largest nitrogen application in early fall, because cool weather favours root growth and food storage.✓ Answer
   • C.Apply the largest nitrogen application during winter dormancy, because the nutrients are stored until spring.
   • D.Apply the largest nitrogen application in late spring, because that is when top growth is fastest and uses it up.

   Cool-season grasses grow best in cool weather, so autumn nitrogen is spent on root growth and stored carbohydrate rather than on rapid leaf production. Heavy mid-summer nitrogen forces succulent top growth exactly when the plant is already under heat stress, increasing disease and thinning; dormant turf cannot take nutrients up at all.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: FertilityReport a problem with this question

2. 2. Two neighbouring lawn areas take the same foot traffic and both thin out. One is Kentucky bluegrass, the other perennial ryegrass. Why does the bluegrass area close its own bare spots while the ryegrass area does not?

   • A.Bluegrass leaves lie flat and lean sideways over the gap, while ryegrass leaves stand upright and cannot cover it.
   • B.Bluegrass spreads by underground rhizomes into the gap; ryegrass is a bunch type that only tillers at its own crown.✓ Answer
   • C.Bluegrass seed in the soil germinates every season, while ryegrass seed loses its viability within a few weeks.
   • D.Bluegrass roots far deeper than ryegrass, and deep roots automatically raise new plants into any bare surface area.

   Rhizomatous grasses produce lateral underground stems that send up new shoots some distance from the parent plant, so worn areas are recolonised without any help. Bunch-type grasses expand only by adding tillers at the existing crown, so the plant gets wider by a leaf or two but never crosses a gap.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Cultural RequirementsReport a problem with this question

3. 3. A tall fescue lawn has a worn strip about two feet wide beside a gate; the turf around it is healthy and well fed. What is the appropriate repair, and why?

   • A.Overseed or sod the bare area, because tall fescue is a bunch grass and will not creep in from the edges.✓ Answer
   • B.Water the bare area daily, because constant moisture makes the existing crowns divide and fill in the gap.
   • C.Lower the mowing height over that area, because close mowing encourages the neighbouring plants to spread.
   • D.Fertilize the surrounding turf heavily, because the extra nitrogen will push runners across the bare ground.

   Growth habit decides the repair method: a bunch grass has no rhizomes or stolons, so no amount of fertilizer, water or close mowing will move plants sideways into the void. New plants must be introduced as seed or sod, and close mowing would in fact weaken the surrounding stand further.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Cultural RequirementsReport a problem with this question

4. 4. A lawn maintained at 2.5 inches was missed for two weeks and now stands about 5 inches tall. What should the technician do on this visit?

   • A.Mow now at about 3.5 inches, then mow again in a few days, stepping the height back down to 2.5 inches.✓ Answer
   • B.Set the deck to 2.5 inches and take one pass, since a single hard cut restores the correct height fastest.
   • C.Set the deck to 2 inches for this cut, since cutting extra low buys time before the next scheduled visit.
   • D.Leave it uncut until the next visit, since mowing grass this tall will shock the stand more than waiting.

   The one-third rule says never remove more than about a third of the leaf blade in one cut; from 5 inches that is roughly 3.3 inches, so the height comes down in stages over successive mowings. Removing more at once strips the photosynthetic tissue, halts root growth while the plant rebuilds leaf, and leaves the stand open to weeds.

   Source: NALP Landscape Training Manual for Maintenance Technicians, Turf Maintenance chapter — one-third mowing ruleReport a problem with this question

5. 5. Why does a lawn kept at the higher end of its recommended mowing range generally develop deeper roots and carry fewer weeds than the same lawn cut short?

   • A.Taller leaves shed rain away from the crown, so less water reaches weed seed and roots dive to find it.
   • B.Short mowing removes the growing point, so the plant has to rebuild its roots from seed every single season.
   • C.Taller turf stays cooler at night, and the cooler crown keeps the plant from making weed-attracting sugars.
   • D.More leaf area supports a bigger root system, and the taller canopy shades soil so weed seed germinates poorly.✓ Answer

   Root depth is roughly proportional to the leaf area the plant is allowed to keep, because leaves make the carbohydrate that roots are built from. The same taller canopy shades the soil surface, and most annual weed seed needs light and warm bare soil to germinate, so a taller cut suppresses weeds without any chemical.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Cultural RequirementsReport a problem with this question

6. 6. How does a dull mower blade injure turf, and how does that injury look across the lawn a day or two after mowing?

   • A.It cuts the tip too cleanly at an angle, which seals the leaf so it cannot transpire and the whole blade yellows.
   • B.It presses the leaf surface flat as it passes, which leaves a glossy striping that fades once the turf is watered.
   • C.It scalps the crowns instead of the tips, which leaves round brown patches wherever the deck crossed a high spot.
   • D.It tears and shreds the leaf tips, which dry to a frayed whitish-tan cast and open entry points for disease.✓ Answer

   A sharp blade severs the leaf cleanly and the small wound closes quickly, while a dull blade beats the leaf off and leaves a ragged tip with a large exposed surface. That torn tissue desiccates to a whitish-tan colour visible over the whole lawn and gives fungal pathogens an easy entry, which is why blades are sharpened on a routine schedule.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Equipment and Tools: MowingReport a problem with this question

7. 7. A crew arrives after an overnight rain and the turf is still soaking wet. What is the main reason to postpone mowing?

   • A.Wet turf grows faster right after rain, so cutting it now removes far more than one third of the leaf blade.
   • B.Wet soil holds nitrogen in solution, and mowing then carries the nutrients off the site in the wet clippings.
   • C.Wet blades are heavier and dull the cutting edge within minutes, so a full set of blades is ruined in one lawn.
   • D.Wet blades bend from the cutter and clump on the surface, giving a ragged cut, smothered patches and rutting.✓ Answer

   A wet leaf is limp and lays over instead of standing into the cutter, so the cut is uneven and the heavy clippings mat together into clumps that smother the turf beneath and spread disease. Saturated soil also compacts and ruts under mower wheels, and wet clippings pack the deck and discharge chute.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Equipment and Tools: MowingReport a problem with this question

8. 8. During a program review the discussion turns to potassium. What does potassium mainly contribute to turfgrass, compared with nitrogen and phosphorus?

   • A.Potassium establishes new roots at seeding, while nitrogen hardens the plant for winter and phosphorus greens the leaf.
   • B.Potassium improves tolerance of drought, cold and disease, while nitrogen drives shoot growth and phosphorus rooting.✓ Answer
   • C.Potassium raises soil pH as it dissolves, while nitrogen lowers it and phosphorus holds the pH steady all season long.
   • D.Potassium gives the dark green colour and fast shoot growth, while nitrogen builds roots and phosphorus resists drought.

   The three numbers on a fertilizer bag are the percentages by weight of nitrogen, phosphate and potash, in that order, and each drives a different process: nitrogen fuels leaf and shoot growth and colour, phosphorus supports root development and establishment, and potassium regulates the plant's water use and cell function so it withstands drought, cold and disease.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: FertilityReport a problem with this question

9. 9. What is the practical trade-off between a water-soluble (quick-release) nitrogen source and a slow-release nitrogen source?

   • A.Quick-release greens up fast but is short-lived and can burn; slow-release feeds evenly longer with less burn risk.✓ Answer
   • B.Quick-release feeds evenly for months and cannot burn; slow-release works only in cold soil and fades in a week.
   • C.Quick-release supplies the nitrogen and slow-release supplies the potassium, so each is used in a different season.
   • D.Quick-release must be watered in and slow-release must not be; otherwise the two behave alike in the root zone.

   A soluble source dissolves immediately, so all of its nitrogen and salt reach the plant at once: colour responds within days, the effect is gone in a few weeks, and the salt concentration can burn. Coated and natural organic sources release gradually as moisture, temperature or microbes act on them, giving a longer even feed at lower burn risk.

   Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: FertilityReport a problem with this question

10. 10. Two days after a granular fertilizer application, straight tan strips appear in the lawn that exactly match the spreader's overlapping wheel paths. What happened?

    • A.The fertilizer salts pulled moisture out of the leaf and root tissue where passes overlapped, drying the turf.✓ Answer
    • B.The granules shaded the leaf along each wheel line, and the shaded tissue lost its chlorophyll and turned brown.
    • C.The spreader wheels crushed the crowns along each pass, and the bruised plants died back in that same pattern.
    • D.The nitrogen washed to the low side of each pass and starved those strips, which faded from lack of feeding.

    Fertilizer burn is osmotic, not nutritional: concentrated soluble salts in the soil water pull moisture out of root and leaf cells faster than the plant can replace it, so the tissue desiccates. The pattern follows the applicator, which is why an overlapped or double-covered strip burns while correctly covered turf does not, and why product is watered in promptly.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: FertilityReport a problem with this question

11. 11. A bermudagrass lawn in a region with cold winters is given a heavy nitrogen application in late autumn, shortly before the first hard frost. What is the likely result?

    • A.It pushes tender new growth into dormancy season, so winterkill is more likely and spring recovery is slower.✓ Answer
    • B.It holds the colour all winter because nitrogen prevents dormancy, with no other effect on the stand at all.
    • C.It is stored in the rhizomes over winter, so the lawn greens up several weeks earlier than untreated turf.
    • D.It has no effect at all, because dormant warm-season grass cannot take up any nitrogen until the soil warms up again.

    Warm-season turf is fed during its active summer growth and needs to harden off before cold weather, so late nitrogen stimulates succulent shoot tissue at exactly the wrong time. That soft growth is far less cold-hardy and it also draws on stored carbohydrate the plant needs to survive dormancy, so damage and slow green-up follow.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: FertilityReport a problem with this question

12. 12. A soil test on a cool-season lawn reports a pH of 5.2. The lawn has been fertilized on schedule but is still pale and weak. What should be done, and why?

    • A.Apply a heavier nitrogen rate, because pH affects only soil life and pale colour always means short nitrogen.
    • B.Apply gypsum to correct the pH, because gypsum neutralises acid soil faster than any other turf amendment.
    • C.Apply elemental sulfur to lower the pH further, because acid soil is what keeps iron and nitrogen fully available.
    • D.Apply lime to raise the pH, because acid soil ties up nitrogen, phosphorus and potassium away from the roots.✓ Answer

    Soil pH matters because it governs nutrient availability: outside the range turfgrass prefers, applied nutrients become chemically bound and the plant cannot take them up, so more fertilizer does not fix a pale lawn. Lime raises pH on acid soil and elemental sulfur lowers it on alkaline soil; gypsum supplies calcium and sulfur but does not change pH.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Adjusting pHReport a problem with this question

13. 13. What is thatch, and what most often causes it to build up to a damaging depth?

    • A.A layer of grass clippings lying on the surface, built up whenever clippings are returned to the lawn instead of bagged.
    • B.A layer of undecomposed stems and roots at the soil surface, built up by heavy nitrogen and slow decomposition.✓ Answer
    • C.A layer of compacted soil just under the crowns, built up by mower wheels running the same line every week.
    • D.A layer of dust and dressing sitting on top of the leaf, built up by topdressing more than once in a season.

    Thatch is the spongy mat of stems, crowns and roots between the green leaves and the soil, and it accumulates when tissue is produced faster than soil microbes can break it down. Excess nitrogen, low soil biological activity, compaction and unfavourable pH all tip that balance; leaf clippings are mostly water and decompose quickly, so returning them does not create thatch.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Equipment and Tools: DethatchingReport a problem with this question

14. 14. A heavily used lawn has hard soil, shallow roots and irrigation that runs off instead of soaking in. Which operation addresses the underlying problem, and how does it work?

    • A.Sand topdressing, which adds a layer over the surface and by doing so restores pore space in the soil below.
    • B.Solid-tine spiking, which drives tines in without lifting soil and by doing so relieves compaction at each hole.
    • C.Core aeration, which lifts out soil plugs so that air, water and roots can move into the compacted layer.✓ Answer
    • D.Vertical dethatching, which slices the organic layer and by doing so loosens the mineral soil underneath.

    Compaction is a loss of pore space, so relief requires physically removing soil to create new pores. Hollow-tine core aeration lifts plugs out and leaves open channels for air, water and root growth; a solid tine displaces soil sideways and can compact the wall of the hole further, while dethatching and topdressing act on the surface layer only.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Equipment and Tools: AerationReport a problem with this question

15. 15. Why does deep, infrequent irrigation produce a deeper root system than light watering applied every day?

    • A.Daily watering cools the soil below what roots need, so growth stops near the surface and restarts deeper.
    • B.Water reaches well into the root zone and the surface dries between cycles, so roots follow it downward.✓ Answer
    • C.The larger volume pushes soil particles apart, so the roots are physically forced down into the loose soil.
    • D.Light watering leaches nitrogen past the roots, so the plant grows fewer roots with nothing left to feed them.

    Roots proliferate where soil moisture and oxygen are both available. Wetting the full root zone and then letting the top dry pulls root growth downward, while daily light watering keeps only the top inch or two moist, so the plant has no reason to root deeper and becomes dependent on the next irrigation.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Watering RequirementsReport a problem with this question

16. 16. A lawn has had repeated fungal disease outbreaks. Its irrigation currently starts at 7 p.m. What change should the technician recommend, and why?

    • A.Move the start to midday, so the sun sterilises the leaf surface while the water is sitting on the turf.
    • B.Move the start to early morning, so the leaves dry soon after sunrise and are not left wet all night.✓ Answer
    • C.Move the start to late night, so the turf takes up water while it is cool and none is lost to the wind.
    • D.Keep the evening start but run it nightly, so a constant film of water rinses spores off the leaf blades.

    Most turf pathogens need extended leaf wetness to infect, so the length of time the blade stays wet is the controlling factor. Early-morning irrigation keeps evaporation and wind losses low like an evening cycle, but the canopy dries within a few hours of sunrise instead of staying wet all night, which shortens the wetness period disease depends on.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Watering RequirementsReport a problem with this question

17. 17. On a hot afternoon part of a lawn takes on a dull blue-grey cast, and footprints stay visible after someone walks across it. What does this indicate?

    • A.The turf has been scalped, and the exposed stems show grey where the mower took off the green leaf tissue.
    • B.The turf has been over-watered, and saturated soil has starved the roots so the leaves have collapsed flat.
    • C.The turf is short of nitrogen, and this blue-grey colour is the first stage of the yellowing that follows.
    • D.The turf is beginning to wilt for lack of water, and the leaves have lost the turgor that springs them back.✓ Answer

    A blue-grey or smoky cast plus persistent footprinting is the classic early signal of moisture stress: cells lose turgor pressure, the leaf folds or rolls and no longer springs back when it is bent by a foot. Catching it at this stage allows irrigation before the turf browns, and it appears first on slopes, sandy spots and areas nearest heat-radiating pavement.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Watering RequirementsReport a problem with this question

18. 18. In late summer, irregular brown patches appear in a lawn. The turf inside them lifts up easily like loose carpet, and skunks have been digging around the edges. What is the most likely cause?

    • A.Scalping by the mower on high spots, which browns the crowns in a pattern that follows the ground contours.
    • B.A dog urinating on the lawn, which burns the centre of each spot and leaves a dark green ring around it.
    • C.White grubs feeding on the roots below the crowns, which cuts the turf loose and draws animals that dig.✓ Answer
    • D.Drought on a shallow-rooted stand, which browns the driest areas first while the turf stays firmly anchored.

    Symptoms are separated by their pattern and by what is happening below the surface. Root-feeding grubs sever the turf's anchorage, so the sod rolls back by hand — a test drought, scalping and urine injury all fail — and the digging by skunks, raccoons or birds is secondary damage from animals hunting the larvae. Confirming the insect by inspection comes before any treatment decision.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Pest ManagementReport a problem with this question

19. 19. A client asks for a crabgrass pre-emergent and an overseeding on the same spring visit. What should the technician explain?

    • A.A pre-emergent feeds the new seedlings while it works, so doing both together is the standard way to renovate.
    • B.A pre-emergent kills seedlings as they germinate and cannot tell crabgrass from turf seed, so separate the jobs.✓ Answer
    • C.A pre-emergent seals the soil surface against water, so the new seed simply needs a heavier watering schedule.
    • D.A pre-emergent only kills weeds that are already up, so it can go down with the seed and will not touch the seedlings.

    A pre-emergent works by leaving a chemical barrier in the germination zone that kills weed seedlings as they emerge; it acts on the process of germination, not on a particular species, so desirable seed sown into it is killed as well. Post-emergent products are the ones that act on weeds already growing, and the label is the legally binding instruction on any waiting interval.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Pest ManagementReport a problem with this question

20. 20. What is the most effective long-term control for broadleaf weeds in a home lawn?

    • A.A blanket herbicide application on a fixed calendar schedule, every spring and again every autumn.
    • B.Hand pulling every visible weed weekly, which is the only method that takes out the whole tap root.
    • C.Correct mowing height, fertility and watering that keep the stand dense enough to crowd weeds out.✓ Answer
    • D.Close mowing several times a season, which cuts the weeds off below the height that they can tolerate.

    Weeds colonise openings, so the primary control is a dense, vigorous stand that leaves no bare soil and no light at the surface for weed seed. Correct cultural practice is therefore the foundation of an integrated program; calendar spraying treats the symptom without closing the openings, and close mowing actually thins the turf and invites more weeds.

    Source: NALP Landscape Industry Certified Technician (Exterior) — Turfgrass Maintenance Principles: Pest ManagementReport a problem with this question

Practice questions based on the published content areas of the National Association of Landscape Professionals' Landscape Industry Certified Technician (Exterior) programme — the universal safety and hazard-communication elements every candidate takes, plus the plan reading, horticultural principles and calculation content behind the installation and maintenance specialties — together with standard horticulture, soils, turfgrass and hardscape construction references. This site is not affiliated with or endorsed by the National Association of Landscape Professionals. This bank covers written knowledge only; where a certification programme also assesses hands-on skill, that part is judged in the field and cannot be practised on a screen. Irrigation system design and troubleshooting, and arboriculture, are covered by our separate irrigation and arborist banks rather than here. Landscape work is governed by pesticide, licensing, water-use and vehicle rules that vary by state and locality — confirm what applies where you work, and confirm current certification requirements with NALP before testing. About NALP certification →