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Texas A&M AgriLife Extension Master Gardener
Program Questions And Correct Answers Plus
Rationales 2025
- What is the best soil pH range for most vegetables in Texas? A. 4.5–5. B. 5.0–6. C. 6.0–7. D. 7.5–8. Most vegetables grow best in slightly acidic to neutral soils, which is in the 6.0– 7.0 pH range.
- What is the main benefit of adding organic matter to sandy soils? A. Raises pH B. Improves water and nutrient holding capacity C. Increases compaction D. Promotes erosion Sandy soils drain quickly and don’t hold nutrients well. Organic matter increases both moisture and nutrient retention.
- Which of the following insects is a beneficial predator in the garden? A. Cabbage looper B. Squash vine borer C. Lady beetle (ladybug)
D. Whitefly Lady beetles eat aphids and other soft-bodied insects, making them beneficial.
- What is the proper spacing when planting tomatoes to prevent disease? A. 6 inches B. 1 foot C. 2 feet D. 3 feet or more Good airflow helps reduce fungal diseases, so wider spacing is recommended.
- Which plant is most tolerant of Texas drought conditions? A. Hydrangea B. Texas sage (Leucophyllum frutescens) C. Fern D. Impatiens Texas sage is native and highly drought-tolerant, requiring minimal irrigation.
- Which part of the plant is responsible for photosynthesis? A. Root B. Stem C. Leaf D. Flower Chloroplasts in leaves capture sunlight to create energy through photosynthesis.
- What is the term for a plant that completes its life cycle in one season? A. Biennial B. Annual
11.What is the function of mulch in a landscape? A. Increases pests B. Conserves soil moisture and reduces weeds C. Adds acidity D. Inhibits root growth Mulch helps retain soil moisture, suppresses weeds, and improves soil quality. 12.When should spring-blooming bulbs like tulips be planted in Texas? A. Late spring B. Fall C. Summer D. Anytime Fall planting gives bulbs the required chill period before spring growth. 13.Which irrigation method is most water-efficient for garden beds? A. Sprinkler B. Hand watering C. Drip irrigation D. Flood irrigation Drip systems deliver water directly to roots, reducing evaporation and runoff. 14.What is a soil test used to determine? A. Pest presence B. Nutrient levels and pH C. Soil texture
D. Organic matter content only A soil test reveals nutrient content and soil pH, essential for proper fertilization. 15.What is the ideal time to prune oak trees in Texas to prevent oak wilt? A. March–May B. Summer C. Late fall to mid-winter D. Early spring Oak wilt is spread by beetles active in spring and summer, so pruning is safest during dormancy. 16.Which plant propagation method is used for succulents? A. Grafting B. Division C. Air layering D. Leaf cuttings Succulents often propagate successfully from leaf cuttings placed in dry soil. 17.What is compost? A. Bagged topsoil B. Decomposed organic matter C. Inorganic fertilizer D. Mulch Compost is made from decomposed plant material and improves soil health. 18.What causes blossom-end rot in tomatoes?
D. Daily pruning Rotating crops prevents pests and diseases from becoming established. 22.Which plant nutrient promotes green, leafy growth? A. Phosphorus B. Nitrogen C. Potassium D. Sulfur Nitrogen supports chlorophyll production and leafy development. 23.Which of the following is a warm-season grass? A. Kentucky bluegrass B. Bermudagrass C. Tall fescue D. Ryegrass Bermudagrass thrives in Texas summers and is commonly used in lawns. 24.What is deadheading? A. Root cutting B. Removing mulch C. Removing spent flowers D. Cutting stems below soil Deadheading encourages more blooming and maintains plant appearance. 25.What is the best mulch depth around trees? A. 1 inch B. 2–4 inches
C. 6 inches D. 10 inches A depth of 2–4 inches retains moisture and suppresses weeds without suffocating roots. 26.What tool is best for cutting small branches? A. Trowel B. Lopper C. Hand pruners D. Saw Hand pruners are ideal for branches under ½ inch thick. 27.What does full sun mean? A. 2 hours of sun B. 6 or more hours of direct sunlight daily C. Shade in afternoon D. Indirect light “Full sun” is defined as 6+ hours of direct sunlight per day. 28.Why is staking young trees important? A. Keeps roots dry B. Prevents disease C. Supports upright growth until roots establish D. Increases photosynthesis Staking prevents wind damage until the tree can support itself. 29.Which of the following is a nitrogen-fixing plant?
D. English ivy Gregg’s mistflower is known for attracting butterflies and bees. 33.Which of the following best describes loam soil? A. Mostly sand B. Mostly clay C. Balanced sand, silt, and clay D. Mostly organic matter Loam is ideal for plant growth due to its balance and drainage properties. 34.What is a good example of an evergreen shrub in Texas? A. Crape myrtle B. Yaupon holly C. Hibiscus D. Pecan Yaupon holly retains its leaves year-round and tolerates drought. 35.When should you harvest onions in Texas? A. When seeds appear B. When tops fall over and begin to dry C. When leaves are dark green D. Before flowering Fallen and dry tops indicate onions are mature and ready for harvest. 36.What causes powdery mildew? A. Insects B. Fungal spores
C. Nutrient deficiency D. Sunlight Powdery mildew is caused by fungal spores that thrive in humid conditions. 37.Which of these is a cool-season vegetable? A. Okra B. Watermelon C. Broccoli D. Peppers Broccoli grows best in cooler temperatures and bolts in heat. 38.Which flower is best for attracting hummingbirds? A. Marigold B. Salvia C. Pansy D. Chrysanthemum Salvia produces tubular flowers filled with nectar. 39.Which fruit tree requires chill hours to bear fruit? A. Fig B. Pomegranate C. Peach D. Loquat Peaches need a certain number of cold hours to produce fruit properly. 40.What is a sign of spider mite infestation?
D. Zone 10 Central Texas is generally Zone 8, meaning average minimum temps of 10–20°F. 44.What causes leaf scorch? A. Bacteria B. Drought and wind exposure C. Aphids D. Cold injury Scorching is caused by water loss exceeding water uptake, often from drought. 45.Which of these is best suited for xeriscaping? A. Hydrangea B. Mexican feathergrass C. Fern D. Hostas Mexican feathergrass is drought-tolerant and low-maintenance. 46.What soil texture drains the fastest? A. Clay B. Sand C. Loam D. Silt Sand has large particles and drains quickly. 47.What is the most common method to manage scale insects? A. Tilling B. Horticultural oil sprays
C. Baking soda D. Freezing Horticultural oils suffocate scale insects. 48.What is a good indoor plant for low light? A. Cactus B. Snake plant C. Marigold D. Petunia Snake plant thrives in low light and needs little care. 49.Why rotate tomato crops each year? A. Improve fruit size B. Change soil pH C. Prevent disease buildup D. Speed germination Rotating tomatoes reduces risk of soil-borne diseases like blight. 50.What is the main cause of lawn thatch? A. Earthworms B. Over-fertilization and shallow watering C. Poor mowing D. Lack of sun Excess fertilizer and poor watering practices promote shallow roots and thatch. 51.What is the most effective method for reducing compacted soil?
Pruning spring bloomers after flowering preserves blooms and encourages next year’s growth. 55.What does “xeriscaping” refer to? A. Using invasive plants B. Landscaping that reduces water use C. Planting only native trees D. Installing artificial turf Xeriscaping promotes water conservation by using drought-tolerant plants. 56.Which plant part is responsible for transporting water? A. Phloem B. Xylem C. Cambium D. Stomata Xylem tissues move water and dissolved minerals from the roots upward. 57.Which of these is a cool-season turfgrass in Texas? A. Bermudagrass B. Ryegrass C. Zoysiagrass D. St. Augustine Ryegrass thrives in cooler temperatures and is often used for winter overseeding. 58.Which pest is controlled using Bacillus thuringiensis (Bt)?
A. Caterpillars B. Aphids C. Scale insects D. Slugs Bt is a bacterial pesticide specific to caterpillar larvae. 59.Why is drip irrigation better for vegetable gardens? A. Makes weeds grow faster B. Increases nitrogen leaching C. Delivers water directly to plant roots D. Promotes foliar disease Drip systems conserve water and minimize disease by keeping foliage dry. 60.What is “companion planting”? A. Placing similar plants together B. Growing plants that benefit each other C. Planting the same crop repeatedly D. Avoiding crop rotation Companion planting pairs crops that help each other grow or deter pests. 61.What type of pruning removes dead or diseased limbs? A. Heading back B. Sanitation pruning C. Shearing
65.What plant part produces seeds? A. Leaf B. Flower C. Root D. Stem Flowers contain the reproductive organs and produce seeds after pollination. 66.Which of the following trees is native to Texas? A. Maple B. Dogwood C. Texas red oak D. Sycamore Texas red oak is adapted to the climate and soil of Texas. 67.What is the most accurate method to determine when to water? A. Daily schedule B. Wilting plants C. Checking soil moisture 2–3 inches below surface D. Leaf color Soil moisture at root depth is the best indicator of watering need. 68.What type of insect is a lacewing? A. Parasite B. Beneficial predator C. Pollinator
D. Pest Lacewing larvae feed on aphids and soft-bodied pests. 69.Which vegetable requires pollination to produce fruit? A. Lettuce B. Spinach C. Squash D. Broccoli Squash needs pollination to produce viable fruit. 70.What causes nutrient lockout in high-pH soils? A. Excess water B. Nutrients become unavailable to plants C. Cold weather D. Insect damage High pH can make essential nutrients insoluble, leading to deficiencies. 71.What is the purpose of staking tall flowering plants? A. Increase pest resistance B. Prevent lodging or breakage C. Attract pollinators D. Encourage drought tolerance Staking supports weak stems and prevents wind or rain damage. 72.Which plant is best suited for shade?
