Download California Master Gardener Program Questions And Correct Answers Plus Rationales 2025 and more Exams Gardening and Horticulture in PDF only on Docsity!
California Master Gardener Program Questions
And Correct Answers Plus Rationales 2025
- What is the ideal pH range for most vegetable garden soils? A. 4.5–5. B. 6.0–7. C. 7.5–8. D. 5.0–5. Most vegetables grow best in slightly acidic to neutral soils, which fall in the 6.0–7.0 pH range.
- What is the most accurate way to determine soil nutrient levels? A. Observing plant color B. Conducting a soil test C. Measuring soil texture D. Tasting the soil Soil tests provide precise data on nutrient levels and pH, which visual observation cannot.
- What is a benefit of using mulch in the garden? A. Attracts pests B. Increases soil erosion C. Retains soil moisture
D. Raises soil temperature Mulch helps conserve water by reducing evaporation from the soil surface.
- What is a sign of nitrogen deficiency in plants? A. Purple stems B. Yellowing of older leaves C. Brown spots on leaves D. Wilting at night Nitrogen deficiency often causes chlorosis (yellowing) in the older leaves first.
- Which irrigation system is most water-efficient for home gardens? A. Overhead sprinkler B. Flood irrigation C. Drip irrigation D. Hose watering Drip irrigation delivers water directly to plant roots, reducing evaporation and runoff.
- What is the scientific term for a plant’s response to gravity? A. Phototropism B. Hydrotropism C. Gravitropism D. Geotropism Gravitropism (also known as geotropism) is how roots grow downward and shoots upward in response to gravity.
- Why is crop rotation recommended?
D. Vacuole Chloroplasts contain chlorophyll, which captures light energy for photosynthesis. 11.Which of the following best describes loam soil? A. Heavy clay B. Balanced mixture of sand, silt, and clay C. Pure sand D. Mostly organic matter Loam is ideal for gardening because it holds nutrients and water while allowing drainage. 12.What is the best way to manage gophers in a vegetable garden? A. Chemical sprays B. Underground wire mesh barriers C. Overhead netting D. Noise deterrents Physical barriers like hardware cloth prevent gophers from accessing plant roots. 13.What is the primary function of plant roots? A. Photosynthesis B. Water and nutrient absorption C. Pollination D. Transpiration Roots anchor plants and absorb water and minerals from the soil.
14.What type of pruning promotes air circulation and light penetration in fruit trees? A. Heading back B. Thinning cuts C. Shearing D. Topping Thinning removes entire branches at their base, improving light and air movement. 15.Which nutrient primarily promotes flowering and fruit development? A. Nitrogen B. Phosphorus C. Potassium D. Calcium Phosphorus supports root growth, flowering, and fruiting in plants. 16.Which of the following is an invasive species in California? A. California poppy B. Yellow star-thistle C. Toyon D. Coast live oak Yellow star-thistle is a widespread invasive weed in California. 17.What time of day is best for watering plants? A. Early morning B. Noon
21.What is the term for growing different crops in proximity for pest control and efficiency? A. Crop rotation B. Companion planting C. Grafting D. Intercropping Companion planting uses plant pairings that benefit each other, such as pest deterrence. 22.Which of the following plants is native to California? A. Hydrangea B. Ceanothus C. Boxwood D. Gardenia Ceanothus (California lilac) is a drought-tolerant California native. 23.Powdery mildew typically thrives in: A. Dry, windy areas B. Warm days and cool, humid nights C. Constantly wet soils D. Sandy soils Powdery mildew spreads under high humidity with poor airflow. 24.When is the best time to prune deciduous trees?
A. Late summer B. Late winter C. During flowering D. After leaf drop in spring Late winter pruning allows for better visibility and healing before spring growth. 25.The process by which plants lose water vapor through leaves is called: A. Evaporation B. Condensation C. Transpiration D. Respiration Transpiration occurs through stomata and drives water movement from roots to leaves. 26.Which pest transmits Pierce’s Disease in grapevines? A. Leafhopper B. Glassy-winged sharpshooter C. Spider mite D. Thrip This pest spreads the bacterium Xylella fastidiosa, causing Pierce’s Disease. 27.What is vermicomposting? A. Using bacteria to compost B. Using worms to decompose organic material C. Composting in cold climates D. Mulching with straw
31.Which mulch is best for weed suppression? A. Grass clippings B. Wood chips or bark C. Sand D. Straw Thick wood mulch blocks light and prevents weed germination. 32.What is an annual plant? A. Lives for several years B. Completes its life cycle in one year C. Grows year-round D. Only flowers once Annuals grow, flower, set seed, and die within one growing season. 33.What is the purpose of hardening off seedlings? A. Increase flowering B. Acclimate them to outdoor conditions C. Delay flowering D. Prevent pest attack Hardening off gradually exposes seedlings to sunlight and wind before transplanting. 34.A deficiency in which nutrient causes purple leaves in some plants? A. Nitrogen B. Phosphorus C. Iron
D. Potassium Lack of phosphorus can cause purpling, especially in cool soils. 35.Which plant part carries water upward from roots? A. Phloem B. Xylem C. Cambium D. Meristem Xylem vessels transport water and minerals from roots to shoots. 36.A plant that continues vegetative growth but delays flowering is likely exposed to: A. High humidity B. Too much nitrogen C. Low phosphorus D. High calcium Excess nitrogen favors leafy growth over flower and fruit production. 37.Which method best controls weeds without chemicals? A. Sprinkling lime B. Sheet mulching C. Spraying vinegar D. Frequent irrigation Sheet mulching smothers weeds using layers of cardboard and organic material. 38.What is the minimum compost temperature to kill most weed seeds?
D. Ethylene Ethylene is a gaseous hormone responsible for ripening in many fruits. 42.Which component improves soil drainage? A. Clay B. Sand C. Peat moss D. Limestone Sand particles are large and increase pore space, improving drainage. 43.Which pruning technique stimulates dense foliage growth? A. Heading cuts B. Thinning cuts C. Crown reduction D. Root pruning Heading cuts remove terminal buds and encourage lateral growth. 44.What is the best way to prevent fire blight in apples and pears? A. Overhead watering B. Sanitation and pruning infected branches C. Heavy fertilization D. Companion planting Removing infected tissue helps prevent the bacterial disease from spreading. 45.What is an example of abiotic plant damage? A. Powdery mildew B. Frost damage
C. Leaf spot D. Root rot Abiotic disorders are caused by non-living factors like temperature extremes. 46.What garden technique can improve pollination in fruit trees? A. Planting multiple varieties B. Heavy pruning C. Using systemic insecticides D. Removing blossoms Many fruit trees are cross-pollinated and need other varieties nearby. 47.Which tree species is drought-tolerant and native to California? A. Birch B. Valley oak C. Maple D. Elm Valley oak is a native oak adapted to California’s dry summers. 48.What garden condition promotes damping-off disease? A. Dry soils B. High winds C. Overwatering and poor drainage D. Full sun Excess moisture encourages fungal pathogens that kill young seedlings. 49.What is the primary role of mycorrhizal fungi?
A. Seed germination B. Cuttings C. Grafting D. Layering Cuttings involve removing part of a plant and rooting it to produce a clone. 53.A horticultural plant labeled “full sun” requires: A. Less than 2 hours of sun B. At least 6 hours of direct sunlight daily C. Dappled shade D. Morning sun only “Full sun” plants typically need 6 or more hours of direct sunlight to thrive. 54.Which soil texture holds the most water? A. Sand B. Loam C. Clay D. Silt Clay has small particles with high surface area, allowing it to hold more water. 55.What is the function of the phloem in plants? A. Transports sugars from leaves B. Transports water from roots C. Anchors the plant D. Produces flowers Phloem distributes sugars and other organic compounds from the leaves to other plant parts.
56.What is the primary benefit of crop diversity in a garden? A. Increases cost B. Reduces pest pressure and disease C. Requires more irrigation D. Limits soil nutrients Diverse plantings interrupt pest cycles and reduce spread of diseases. 57.When preparing a garden bed, what is the best way to improve compacted soil? A. Add lime B. Incorporate organic matter C. Increase irrigation D. Use chemical softeners Organic matter improves soil structure, aeration, and water retention in compacted soils. 58.What is “deadheading” in gardening? A. Fertilizing with compost B. Removing spent flowers C. Cutting roots D. Watering at night Deadheading encourages further blooming by removing old flowers. 59.Which tool is best for cutting small branches or stems? A. Hoe B. Rake
63.Which insect pest forms honeydew and sooty mold? A. Spider mites B. Aphids C. Cutworms D. Grasshoppers Aphids secrete sugary honeydew, which supports the growth of sooty mold. 64.What is a symptom of root rot? A. Tall, leggy growth B. Wilting despite moist soil C. Purple stems D. Flowering out of season Root rot causes poor water uptake, leading to wilted plants even when soil is moist. 65.Which of the following weeds is known to be highly invasive in California? A. Dandelion B. Scotch broom C. Bermuda buttercup D. Chickweed Scotch broom aggressively spreads and displaces native vegetation. 66.Which compost material is high in nitrogen? A. Dried leaves B. Grass clippings C. Sawdust
D. Straw Green materials like grass clippings provide nitrogen for composting. 67.What is the best way to avoid transplant shock? A. Remove all roots B. Prune heavily C. Water thoroughly after transplanting D. Fertilize immediately Watering deeply helps establish roots and reduce stress in new transplants. 68.What part of the plant produces seeds? A. Roots B. Leaves C. Flowers D. Buds Seeds are produced after fertilization in flowers. 69.What is the best action for managing powdery mildew? A. Water the leaves daily B. Remove infected leaves and increase air flow C. Apply nitrogen fertilizer D. Overhead watering Powdery mildew spreads in humid, stagnant air. Removing infected tissue helps. 70.What is the function of stomata in leaves? A. Support structure B. Gas exchange
