MASTER GARDENER EXAM 2025 – QUESTIONS AND ANSWERS | VERIFIED AND WELL DETAILED
ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
Core Domains
1. Botany and Plant Physiology
2. Soil Science and Plant Nutrition
3. Entomology and Integrated Pest Management (IPM)
4. Plant Pathology and Disease Management
5. Landscape Design and Maintenance
6. Sustainable Gardening and Ecology
7. Pesticide Safety and Environmental Stewardship
8. Ethics and Professional Communication
Introduction
This comprehensive examination is designed to assess the foundational knowledge and practical skills
required of a certified Master Gardener. The test evaluates a candidate's understanding across core
domains, including botany, soil science, pest management, and landscape maintenance. Through a
combination of multiple-choice and scenario-based questions, the exam emphasizes the application
of scientific principles to real-world gardening challenges. It focuses on decision-making, problem-
solving, and the ability to provide sound, research-based horticultural advice to the public. Successful
completion of this exam signifies a commitment to professional standards and environmental
stewardship, ensuring that Master Gardeners are well-prepared to serve as community educators and
leaders in sustainable horticulture.
Section One: Questions 1–100
1. In plant anatomy, what is the primary function of the root cap?
A. To absorb water and nutrients from the soil.
B. To protect the apical meristem as the root pushes through the soil.
C. To conduct water and minerals from the roots to the leaves.
D. To store excess carbohydrates produced during photosynthesis.
🟢B
🔴 Explanation: The root cap is a thimble-like covering over the root tip's apical meristem. Its
primary role is to protect this delicate growing region from physical damage as the root penetrates
the soil.
2. A soil test reveals a pH of 5.5. This soil is considered:
A. Neutral.
B. Slightly alkaline.
C. Moderately acidic.
D. Highly alkaline.
,🟢C
🔴 Explanation: The pH scale ranges from 0 to 14, with 7 being neutral. A pH of 5.5 is below 7,
indicating acidity. It is classified as moderately acidic, which is typical for many regions and affects
nutrient availability.
3. Which of the following is an example of a plant disease caused by a bacterium?
A. Powdery mildew
B. Fire blight
C. Dutch elm disease
D. Rust
🟢B
🔴 Explanation: Fire blight, which affects plants like apples and pears, is a highly destructive
bacterial disease caused by Erwinia amylovora. Powdery mildew, Dutch elm disease, and rust are
caused by fungi.
4. A homeowner reports that their tomato plant leaves are curling upwards and have a purplish
discoloration on the undersides. They suspect a pest, but no insects are visible. What is the most
likely cause?
A. Tomato hornworm
B. Early blight
C. Phosphorus deficiency
D. Root-knot nematode
🟢C
🔴 Explanation: Purple discoloration on the undersides of leaves, especially in conjunction with
upward leaf curling, is a classic symptom of phosphorus deficiency. This is often seen in cool, wet
soils where phosphorus uptake is inhibited.
5. The process by which plants lose water vapor through their stomata is known as:
A. Condensation.
B. Transpiration.
C. Guttation.
D. Respiration.
🟢B
🔴 Explanation: Transpiration is the loss of water vapor from the plant, primarily through the
stomata in the leaves. This process is essential for nutrient transport and cooling the plant.
6. A Master Gardener is advising on a xeriscaping project. Which of the following irrigation
methods is most water-efficient?
A. Overhead sprinklers
B. Soaker hoses
C. Drip irrigation
D. Hand watering with a hose
🟢C
🔴 Explanation: Drip irrigation delivers water directly to the plant's root zone, minimizing
, evaporation and runoff, making it the most water-efficient method for xeriscaping and general
water conservation.
7. What is the primary function of the xylem tissue in a plant?
A. To transport sugars produced in the leaves to the rest of the plant.
B. To transport water and dissolved minerals from the roots to the leaves.
C. To provide structural support for the plant.
D. To exchange gases with the atmosphere.
🟢B
🔴 Explanation: Xylem is the vascular tissue responsible for the upward transport of water and
mineral nutrients from the roots to the rest of the plant. Phloem transports sugars.
8. An example of a complete fertilizer is:
A. 10-0-10
B. 21-0-0
C. 10-10-10
D. 0-20-0
🟢C
🔴 Explanation: A complete fertilizer contains all three primary macronutrients: nitrogen (N),
phosphorus (P), and potassium (K). The numbers in 10-10-10 represent the percentage by weight
of each nutrient, in that order.
9. A lawn has a thriving population of white grubs. This is a sign of an infestation of which pest?
A. Armyworms
B. Japanese beetles
C. Chinch bugs
D. Sod webworms
🟢B
🔴 Explanation: White grubs are the larval stage of several scarab beetles, including the Japanese
beetle. They live in the soil and feed on grass roots, causing damage to lawns.
10. Which of the following is the correct first step in diagnosing a plant health problem?
A. Apply a broad-spectrum pesticide.
B. Identify the plant species.
C. Send a soil sample to a lab.
D. Increase the watering frequency.
🟢B
🔴 Explanation: The first step in any plant health diagnosis is to correctly identify the plant.
Knowing the species and its specific requirements helps distinguish between normal characteristics
and potential problems.
11. The term "loam" refers to soil that has a roughly equal mixture of:
A. Sand and silt.
B. Sand, silt, and clay.
ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
Core Domains
1. Botany and Plant Physiology
2. Soil Science and Plant Nutrition
3. Entomology and Integrated Pest Management (IPM)
4. Plant Pathology and Disease Management
5. Landscape Design and Maintenance
6. Sustainable Gardening and Ecology
7. Pesticide Safety and Environmental Stewardship
8. Ethics and Professional Communication
Introduction
This comprehensive examination is designed to assess the foundational knowledge and practical skills
required of a certified Master Gardener. The test evaluates a candidate's understanding across core
domains, including botany, soil science, pest management, and landscape maintenance. Through a
combination of multiple-choice and scenario-based questions, the exam emphasizes the application
of scientific principles to real-world gardening challenges. It focuses on decision-making, problem-
solving, and the ability to provide sound, research-based horticultural advice to the public. Successful
completion of this exam signifies a commitment to professional standards and environmental
stewardship, ensuring that Master Gardeners are well-prepared to serve as community educators and
leaders in sustainable horticulture.
Section One: Questions 1–100
1. In plant anatomy, what is the primary function of the root cap?
A. To absorb water and nutrients from the soil.
B. To protect the apical meristem as the root pushes through the soil.
C. To conduct water and minerals from the roots to the leaves.
D. To store excess carbohydrates produced during photosynthesis.
🟢B
🔴 Explanation: The root cap is a thimble-like covering over the root tip's apical meristem. Its
primary role is to protect this delicate growing region from physical damage as the root penetrates
the soil.
2. A soil test reveals a pH of 5.5. This soil is considered:
A. Neutral.
B. Slightly alkaline.
C. Moderately acidic.
D. Highly alkaline.
,🟢C
🔴 Explanation: The pH scale ranges from 0 to 14, with 7 being neutral. A pH of 5.5 is below 7,
indicating acidity. It is classified as moderately acidic, which is typical for many regions and affects
nutrient availability.
3. Which of the following is an example of a plant disease caused by a bacterium?
A. Powdery mildew
B. Fire blight
C. Dutch elm disease
D. Rust
🟢B
🔴 Explanation: Fire blight, which affects plants like apples and pears, is a highly destructive
bacterial disease caused by Erwinia amylovora. Powdery mildew, Dutch elm disease, and rust are
caused by fungi.
4. A homeowner reports that their tomato plant leaves are curling upwards and have a purplish
discoloration on the undersides. They suspect a pest, but no insects are visible. What is the most
likely cause?
A. Tomato hornworm
B. Early blight
C. Phosphorus deficiency
D. Root-knot nematode
🟢C
🔴 Explanation: Purple discoloration on the undersides of leaves, especially in conjunction with
upward leaf curling, is a classic symptom of phosphorus deficiency. This is often seen in cool, wet
soils where phosphorus uptake is inhibited.
5. The process by which plants lose water vapor through their stomata is known as:
A. Condensation.
B. Transpiration.
C. Guttation.
D. Respiration.
🟢B
🔴 Explanation: Transpiration is the loss of water vapor from the plant, primarily through the
stomata in the leaves. This process is essential for nutrient transport and cooling the plant.
6. A Master Gardener is advising on a xeriscaping project. Which of the following irrigation
methods is most water-efficient?
A. Overhead sprinklers
B. Soaker hoses
C. Drip irrigation
D. Hand watering with a hose
🟢C
🔴 Explanation: Drip irrigation delivers water directly to the plant's root zone, minimizing
, evaporation and runoff, making it the most water-efficient method for xeriscaping and general
water conservation.
7. What is the primary function of the xylem tissue in a plant?
A. To transport sugars produced in the leaves to the rest of the plant.
B. To transport water and dissolved minerals from the roots to the leaves.
C. To provide structural support for the plant.
D. To exchange gases with the atmosphere.
🟢B
🔴 Explanation: Xylem is the vascular tissue responsible for the upward transport of water and
mineral nutrients from the roots to the rest of the plant. Phloem transports sugars.
8. An example of a complete fertilizer is:
A. 10-0-10
B. 21-0-0
C. 10-10-10
D. 0-20-0
🟢C
🔴 Explanation: A complete fertilizer contains all three primary macronutrients: nitrogen (N),
phosphorus (P), and potassium (K). The numbers in 10-10-10 represent the percentage by weight
of each nutrient, in that order.
9. A lawn has a thriving population of white grubs. This is a sign of an infestation of which pest?
A. Armyworms
B. Japanese beetles
C. Chinch bugs
D. Sod webworms
🟢B
🔴 Explanation: White grubs are the larval stage of several scarab beetles, including the Japanese
beetle. They live in the soil and feed on grass roots, causing damage to lawns.
10. Which of the following is the correct first step in diagnosing a plant health problem?
A. Apply a broad-spectrum pesticide.
B. Identify the plant species.
C. Send a soil sample to a lab.
D. Increase the watering frequency.
🟢B
🔴 Explanation: The first step in any plant health diagnosis is to correctly identify the plant.
Knowing the species and its specific requirements helps distinguish between normal characteristics
and potential problems.
11. The term "loam" refers to soil that has a roughly equal mixture of:
A. Sand and silt.
B. Sand, silt, and clay.
