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Gardening Glossary: Practical Gardening Terms and Definitions

Read through these practical gardening terms and definitions to give yourself an overview. Then, as you gain experience in your garden, you will see the words and meanings come to life. Don’t worry about memorizing everything; you will learn as you go. Refer to this page as needed. You’ve got this! 

Starting a garden can feel overwhelming. You may have heard many gardening terms and phrases but didn’t clearly understand them. This post lists many helpful gardening terms with their definitions. 



Disclaimer: This post may contain affiliate links. See my disclosure policy for more information.


ACIDIC SOIL: Soil with a pH lower than 7.0. Most plants prefer slightly acidic soil. 

AIRFLOW: Proper spacing between and around plants allows air to circulate and prevents mold and moisture-related diseases. Airflow around plants is as essential as sunshine and water.

ALKALINE SOIL: Soil with pH higher than 7.0. Arizona native soils are typically alkaline. 

ANNUAL: A plant that completes its life cycle from seed to flower to production of seeds within one growing season, after which the entire plant dies. 

BARE ROOT: Dormant plants sold with roots exposed rather than in a container with soil. When purchasing and planting a bare root plant, note that roots should be kept moist until you can plant them in soil.

BENEFICIAL INSECTS: Insects or the larvae of insects that prey on pests and their eggs. Common beneficial insects include ladybugs, lacewings, hover flies, parasitic wasps, praying mantis, soldier bugs, and spiders. Read more in this blog post.



BIENNIAL: A plant that requires two years to complete its life cycle from seed to flower to production of seeds, followed by the plant’s death. Examples of biennials include carrots, onions, and parsley.

BLANCHING: Blocking the light from a plant to keep it paler in color or milder in flavor.

BOLTING: Producing seeds or flowers prematurely. Annual and biennial plants switch from storing energy to producing seeds at the end of their life cycle. When a plant is under stress, it may pre-maturely make a flowering stem that produces seeds. However, once a plant bolts, it often becomes bitter. Read more in this blog post.

BUD UNION: Place where the shoot or bud (scion) is grafted onto the rootstock. 

BULB: Storage structure that contains the complete life cycle of a plant. It remains dormant until conditions are favorable for growth. Examples of bulbs include garlic and onions



CALICHE: A type of sedimentary rock formed from calcium carbonate. Common in desert soils. Causes problems with lack of drainage.

CHILL HOURS: The number of hours when the air temperature between 32°F and 45°F. Winter hours above 60°F are subtracted from the total. The minimum period of cold weather a fruit-bearing tree needs to blossom and produce fruit. Cold climates have more chill hours than warm climates. See also VERNALIZATION.

CHLOROSIS: Yellowing of leaves due to chlorophyll breakdown or loss of production. It is often caused by high soil pH, lack of fertility, moisture, pests, or herbicide injury. 


Gardening Glossary: Practical Gardening Terms and Definitions (cont.)


COCONUT COIR: A product made from the fiber of coconut shells and typically sold as pressed bricks; a common ingredient in many potting soils. Coconut coir allows for water retention, drainage, and aeration for roots.

COMPANION PLANTING: The practice of planting different crops to benefit both crops in various ways, including increasing productivity, pest control, and pollination. Read more in this blog post.

COMPOST: A mixture of decayed organic matter used as a soil conditioner or plant fertilizer. It improves soil’s ability to drain well and hold air and water. 

COMPOSTING: The process of combining plant and other organic matter with air and water to encourage microbial activity and decomposition into a form usable as a soil conditioner or plant fertilizer. Read more in this blog post



CONTAINER: Anything filled with soil and used for planting. Range from small to very large. Read more in this blog post.

COOL-SEASON CROP: Vegetables, herbs, or flowers that thrive during cooler months. Often originate from temperate regions.

CORM: Swollen, energy-storing structure (similar to bulbs) of ranunculus, iris, and crocus. 

COVER CROP: Category of crops grown to cover the soil during periods where there would not be anything growing. It can enrich the soil, prevent weeds and erosion, and help with pests and diseases.

CROSS-POLLINATION: Often required with certain types of fruit trees. The second variety of fruit (pollenizer) is planted nearby to increase pollination and yield. 

CUT-AND-COME-AGAIN METHOD: This method is a way to harvest continually from a single plant over several weeks or months rather than harvesting the entire plant. Use this harvesting method with plants such as arugula, celery, kale, lettuce, spinach, and Swiss chard.

DAMPING OFF: Wilting or dying back of young seedlings, often caused by soil-borne fungal pathogens. Seedlings wilt, topple over, and die. 

DAYS TO MATURITY: The amount of time from when the seed or transplant is planted until maturity (meaning the fruit is harvested or the flower blooms). It is usually listed on the seed packet or plant label. 

DEADHEADING: The practice of removing faded blooms from flowers to encourage more buds, improve appearance, and delay seed formation.

DECIDUOUS: A type of tree or shrub that sheds its leaves each year, usually in the autumn. 

DIRECT SOWING: Planting seeds directly in the garden or containers outside, rather than starting from transplant or seeds indoors. Read more in this blog post.



DIVIDING: Dividing a plant means digging it up and separating it into two or more sections. Each section should contain roots and part of the plant. These sections can be planted and become new plants.

DORMANCY: A time when plants’ growth and activity are at a minimum, generally during temperature extremes. 

DRAINAGE: The downward movement of water through the soil. Drainage is often hindered if caliche is present. Poor drainage kills plants because the roots do not receive adequate oxygen. 

DWARF: Smaller and more compact than the typical variety for that type of plant. Fruit is usually a standard size.

ESPALIER: Practice of pruning (usually fruit trees) to encourage flat growth against a vertical surface. 

ESTABLISHED: After planting, the point at which the plant’s roots have begun to spread and grow below ground and above ground, the plant sends out new growth. 

EVERGREEN: A plant or tree that retains its leaves throughout the year and into the following growing season.


Gardening Glossary: Practical Gardening Terms and Definitions (cont.)



FERTILIZE: To apply nutrients to a plant. 

  • Granular fertilizer: dry, pelleted fertilizer.
  • Liquid fertilizer: a liquid fertilizer, usually mixed with water to form a solution.
  • Side dress: sprinkling fertilizer in the soil next to a plant. 
  • Foliar feed: spraying a fertilizer solution onto the leaves of a plant.
  • Soil drench: pouring a fertilizer solution into the soil surrounding the plant.

FROST DATE: Date of the average first or average last freeze that occurs in spring or fall.

FROST HARDY: A plant that can survive a certain amount of freezing temperatures without damage to leaves, stems, or roots.

FROST SENSITIVE: A plant likely to be damaged or killed by freezing temperatures. Read more in this blog post.

FULL SUN: At least six hours (or more) of unobstructed sunlight each day.

GERMINATION: The development of a plant from a seed into a seedling in response to warmth, water, and sometimes light.



GROWING SEASON: The time during the year when conditions are right for plants to grow. Sometimes counted from the date of the last frost in the spring to the first frost in the fall.

HABIT: A plant’s growth pattern; can be described as trailing, upright, spreading, etc.

HAND POLLINATION: Assisting with the transfer of pollen in plants from the male reproductive organ (stamen) to the female reproductive organ (pistil) to form fruit. Use a small paint brush to transfer the pollen or remove the male blossom (long, thin stem) and lightly touch the center of the male flower to the center of the female flower (bulbous stem).

HARDENING OFF: Gradually exposing an indoor / greenhouse-grown plant to increasing periods outside to prevent shock when planted outside. Read more in this blog post.


Gardening Glossary: Practical Gardening Terms and Definitions (cont.)


HARDINESS: A plant’s ability to tolerate cold temperatures. 

HARDINESS ZONE: The geographical zone where certain plants grow best in that particular climate. The hardiness zones show the average annual minimum temperature ranges for a specific area. Awareness of your growing zone helps you know which fruit trees will survive outdoors or if you must bring containers inside during cold months. However, hardiness zones are not a good indicator of summer temperatures. See also USDA PLANTING ZONE



HERBACEOUS: A plant with soft or fleshy tissue. Commonly refers to any non-woody plant, annual, perennial, or bulb. Contrast with woody. 

HÜGELKULTUR (pronounced “hoo-gul-culture”): Gardening technique for building soil structure through layering. Typically logs and other wood layered with soil. Benefits include a reduced need for watering and fertilizer. 

HYBRID: The resulting plant from cross-pollination (intentional or natural) between two or more plants in the same family (genus).

HYDROPHOBIC: “Water hating”. Soil that repels or will not absorb moisture. If the soil has dried out too much, water may drain through the soil without being absorbed. If this happens to your soil, gently dig in it with a garden spade; don’t turn the soil over, just loosen it. Next, repeatedly sprinkle the surface lightly with water. After several sprayings, the soil should begin to break up and loosen, allowing more water to be absorbed.

INTEGRATED PEST MANAGEMENT (IPM): Method of managing pests, weeds, and diseases with the least possible disruption to the surrounding ecosystem. Emphasizes observation and natural, biological solutions.  Read more in this blog post.

IRRIGATION: Watering the garden and surrounding landscape using different methods, including drip systems, soaker hoses, flood irrigation, and hand watering with a hose. Read more in this blog post.



JUNE DROP: Natural thinning by a fruit tree of excess fruit; common on citrus trees. In warm areas, often occurs during May. 

LARVA: The active immature stage of an insect, especially one that differs from the adult. The plural is “larvae”.  

LEGGY: The condition of seedlings when there is not enough light present during germination and early growth. The seedlings stretch towards the light and often become unusable. Read more in this blog post.

MACRONUTRIENTS: Plant nutrients required in percentage quantities: calcium, magnesium, nitrogen, phosphorus, potassium, and sulfur. 


Flowers to Plant Outside & Seeds to Start Indoors Each Month in the Low Desert of Arizona.
• PLANTING GUIDE: Each month lists annual flowers to plant outside & seeds to start indoors.
• BLOOMING GUIDE: Photos show what may be in bloom that month.


MICROCLIMATE: The climate of a small area. It can be a backyard or a portion of a yard. Microclimates are influenced by factors such as hills, hollows, surrounding structures, and existing plants. 

MICRONUTRIENTS: Trace amounts of minerals such as boron, chlorine, copper, iron, maghanese, molybdenum, nicket, and zinc that are needed in parts per million for proper plant development. 

MULCH: A layer of material spread over the surface of the soil. Types of organic mulch include leaves, grass clippings, peat moss, compost, straw, and pine needles. Organic mulch reduces evaporation, regulates temperature, and reduces weeds. Read more in this blog post.



MYCHORHIZA: A symbiotic relationship between certain fungi and roots of plants; literally “fungus root”. The plural is “mycorrhizae”.


Gardening Glossary: Practical Gardening Terms and Definitions (cont.)


NITROGEN: An ingredient in most fertilizers crucial for healthy leafy growth. Plants use more nitrogen than any other nutrient. The amount of nitrogen is listed as the first number in the three numbers on fertilizers (N-P-K).

NO-TILL GARDENING: Minimal disruption to the soil while gardening to minimize disruption to the soil food web. Removing plants by cutting at the base and leaving the roots in place is an easy way to begin no-till practices in your garden. 

OLLA: A clay pot with a narrow neck and bulging body used as a watering technique that reduces evaporation and makes water available where the roots need it. The wider part of the olla is buried in the soil, with the narrow opening remaining above soil level. Fill the olla with water regularly, and it seeps out through the porous wall of the pot into the surrounding soil and root zone of the plant. I use ollas from Growoya.



ORGANIC FERTILIZER: Naturally-occurring fertilizers derived from rock, animal, and plant matter.

ORGANIC GARDENING: Gardening without synthetic pesticides and fertilizers to maintain plant and soil health. Read more in this blog post.

ORGANIC MATTER: Carbon-based material from plants and animals that is capable of decomposition. Includes products of organisms and the decayed remains of dead organisms.

PARTIAL SHADE: Areas of the yard and garden that receive between four to six hours of unobstructed sunlight each day.

PEAT MOSS: Partially decomposed moss remains; used as a common ingredient in potting soil. Peat moss holds water and air, decomposes slowly, improves the texture, and raises soil pH. It is considered a less sustainable option than coconut coir.

PERENNIAL: A non-woody plant that lives for many growing seasons. The top of the plant may die back in the winter and come back each spring from the existing roots. Or the plant may keep its leaves year-round. 

PERLITE: A material formed when volcanic rock is crushed and heated; it is a common ingredient in potting soil. Adding perlite to soil keeps the soil loose and helps with water retention. Perlite retains less water than vermiculite.

PEST: Any organism that can cause disease or injury to plants or plant products. Read more in this blog post.



PHOSPHOROUS: An ingredient in most fertilizers that encourages strong root growth and the development of flowers, fruits, and seeds. The amount of phosphorous is listed as the second number in the three numbers on fertilizers (N-P-K).

PHOTOSYNTHESIS: The process whereby plants use sunlight to turn carbon dioxide into usable energy for the plant.

PINCHING: Removing the top or sucker growth to encourage bushier growth, longer stems, or more blooms. Common on plants such as basil, tomatoes, zinnias, and peppers

PLANT FAMILIES: Plant categories that share broad characteristics and have similar growth requirements and habits. The common names of some plant families and their members include: 

  • Alliums: garlic, onions, chives. 
  • Amaranths: beets, chard, spinach.
  • Asters: lettuce, sunflowers, chamomile. 
  • Brassicas: broccoli, cabbage, cauliflower, kale, kohlrabi, radish.
  • Cucurbits: squash, cucumber.
  • Legumes: beans, peas.
  • Mint: basil, mint, rosemary, sage. 
  • Nightshades: tomatoes, peppers, potatoes, eggplant.
  • Umbels: carrots, celery, cilantro, dill, parsley.

PLANTING GUIDE: A reference that tells the optimal time to plant vegetables, herbs, and flowers based on a specific location or climate.


Planting Calendar for the Low Desert of Arizona

POLLINATION: The transfer of pollen in plants from the male reproductive organ (stamen) to the female reproductive organ (pistil) to form fruit. Some flowering crops have separate male and female blossoms (squash, cucumber), while other crops (tomatoes, eggplant, peppers) have perfect flowers (both male and female organs in one flower). Bees and other pollinators assist in pollination by transferring the pollen from one flower to another or vibrating the flower to distribute the pollen inside the flower.

POLLINATOR: An insect, bird, or animal that transfers pollen from one flower or plant to another. 

POLYCULTURE: A variety of plants in each bed or plot of land. Diversity in plantings attracts a broader assortment of beneficial insects and pollinators. Read more in this blog post.



POTASSIUM: An ingredient in most fertilizers that increases the yield and quality of plants and helps plants resist disease and stress. The amount of potassium is listed as the last number in the series of three numbers on fertilizers (N-P-K).


Gardening Glossary: Practical Gardening Terms and Definitions (cont.)


POTTING SOIL: A blend of ingredients that holds moisture around plants’ roots, provides air for growing roots, and allows for plant drainage in containers. Sometimes called potting medium, container soil, or container mix. The ingredients may include vermiculite, perlite, coconut coir, and peat moss. Read more in this blog post.

POTTING UP: Transferring seedlings to a larger container. Often done when the roots or plant has outgrown the container the seeds were started in and conditions prevent planting outside in the garden. 

POWDERY MILDEW: Common name for one of a group of fungal pathogens that form a white froth on the surfaces of plant parts. Read more in this blog post.


Powdery Mildew
Powdery Mildew

PRUNING: Removal of dead, diseased, overgrown, or unwanted branches.

RESEED: The dropped seed from an annual plant that regrows the following season if conditions are suitable for germination and growth.

RHIZOMES: Fleshy stems that spread horizontally underground and contain several buds or growing points. Examples of rhizomes include ginger and turmeric.

ROOT BALL: The grouping of roots and soil surrounding a plant when removed from the ground or container. 

ROOT BOUND: Plants grown in the same container too long have roots that become tangled and circle the container. Roots restricted in too-small containers become “root bound” and are less likely to flourish after being planted in the garden.

ROOT CROWN: The area of the plant or tree where the roots branch off from the stem or trunk. It is essential not to bury this part of the plant when potting up trees and bushes.

ROOT STOCK: The base of a grafted plant is usually selected for size, hardiness, or disease resistance. 

ROOT ZONE: The soil, water, and oxygen area below ground and around the plant’s roots that supply the plant with water and nutrients. The roots are usually concentrated in the top 18 inches of soil and spread as wide as the plant’s canopy. 

ROW COVER: Lightweight or translucent fabric covers plants to protect them from frost, insects, birds, or other pests. Allows air, light, and water to pass through. 



SEEDLING: The first emergence of growth from seed. Emerging leaves are called cotyledons, while subsequent leaves are called true leaves.

SEED STARTING MIX: Typically a sterile, soil-less mix of peat moss, vermiculite, perlite, or other ingredients. Used when starting seeds indoors. 

SEED TYPES

  • GMO – Genetically modified organism whose genetic material has been altered. 
  • Heirlooms – Generally are open-pollinated varieties more than 50 years old. 
  • Hybrid – Produced by crossing plants from different lines and chosen for desirable characteristics such as disease resistance. The seeds of hybrid plants are usually sterile or not true to type.
  • Open-pollinated – Plant type that produces stable seed characteristics from generation to generation.
  • Organic – Seeds produced using organic gardening methods.

SELF-FRUITFUL: Fruit trees that do not require pollination from a different variety of trees. 

SELF-WATERING CONTAINERS: Containers with a water reservoir and wicking system that, when kept full, allow for a consistent source of moisture for plants. Self-watering containers are helpful if you cannot water your containers daily for plants that need a consistent moisture level, such as tomatoes, and in hot climates where containers dry out quickly.

SHADE: Areas of the yard and garden that do not receive direct sunlight.



SHADE CLOTH: Reduces the amount of sunlight that reaches plants. You can use it to extend the season, reduce temperature, or protect newly-planted seedlings. Shade cloth comes in different coverages. A percentage of 40-60% shade cloth is suitable for vegetables during the summer when temperatures are consistently above 100°F. Read more in this blog post.


Gardening Glossary: Practical Gardening Terms and Definitions (cont.)


SOIL FOOD WEB: All the life (seen and mostly unseen) happening in healthy soil. Minerals, oxygen, and organic matter with microorganisms, earthworms, beetles, and more. Bacteria and fungi coexist in a life cycle with nematodes, protozoa, and micro-anthropods. 

SOIL PH: A measure of soil acidity or alkalinity. It is measured on a scale from 0 (very acidic) to 14 (very alkaline). Most plants grow best when soil pH is between 5.5 and 7.5. A pH of 7 is considered neutral. Each plant has a preferred pH range. The pH level affects which nutrients are available to the plant in the soil.

SOIL TEST: An analysis of a soil sample, usually to determine the nutrient levels and pH. Read more in this blog post.



SQUARE FOOT GARDENING: An intensive gardening method based on planting in one-foot grids. Depending on the fruit, flower, herb, or vegetable size, a certain number of seeds or transplants are planted in each square. Learn more in this blog post.

STAKING: Supporting a plant or tree with poles, twine, or other mechanisms.

SUCCESSION PLANTING: The practice of staggering plantings throughout the growing season to ensure a continual harvest, rather than harvesting all at once.

TENDER: Plants that do not tolerate cold temperatures. 

TERMINAL BUD: The central point on a plant where the new growth originates. Leave the terminal bud in place when harvesting outer leaves (cut-and-come-again method). Cutting off the terminal bud often results in branching below the cut.

THINNING

  • The removal of some plants to make room for the remaining plants to have enough soil, sunlight, water, and airflow to grow well. Thinning often occurs once plants have two sets of true leaves. 
  • Removing excess fruit from fruit trees to allow the remaining fruit to grow larger or prevent limb breakage and damage. 
  • A pruning cut that removes a branch or stem to the point of attachment on another branch or the base of the stem. 

TRELLIS: Vertical structure that provides support to growing plants. Read more in this blog post.



TRANSPIRATION: The process of plants breathing in water from the soil through their roots and out through their leaves.

TRANSPLANT: A young plant somewhat past the seedling stage, also called starts. Transplants usually have several sets of true leaves. Also, the process of moving a plant from one location to a different location. Read more in this blog post.

USDA PLANTING ZONE: System developed as a guide for planting and gardening. The United States is divided into thirteen zones by the lowest annual temperatures. A plant’s “hardiness zone” is the lowest USDA zone it can withstand without dying during cold temperatures. See also HARDINESS ZONE. 


Gardening Glossary: Practical Gardening Terms and Definitions


VERMICOMPOSTING: Worm composting – also called vermicomposting (‘vermi’ = worm) – is the process of using worms to compost food scraps into vermicompost. Read more in this blog post.



VERMICULITE: A common ingredient in potting soil. It is made from a mica rock. Vermiculite absorbs water, makes the soil loose and friable, and adds potassium, calcium, and magnesium. Vermiculite retains more moisture than perlite.

VERNALIZATION: Period of time where seed or plant is exposed to cold temperatures in nature or artificially to induce to initiate or accelerate the flowering process. See also CHILL HOURS.

VERTICAL GARDENING: Growing plants vertically up structures rather than allowing the plant to sprawl along the ground. Vertical gardening allows more sunlight and air to reach the plant, which helps the plant be more productive. Read more in this blog post.



VINING PLANT: A plant that produces climbing or trailing stems from a central point or several points. Vines often require support or a trellis. Read more in this blog post.

WARM-SEASON CROPS: Vegetables, herbs, or flowers that thrive during warmer months and do not tolerate cold or frost. 

WOODY: A plant with hardened stems or trunks. In contrast with herbaceous plants, which have soft stems.

WORM CASTINGS: Worms eat up to half their weight daily in kitchen scraps, and the byproduct of all that eating is worm castings. During digestion, the worms secrete chemicals that break organic matter into nutrition readily available to plants. Worm castings and the chemicals secreted during digestion make up vermicompost.



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