Glossary of Growing Terms

Glossary of Terms

A list of terms commonly used in the growing and gardening industries, with basic definitions.

Johnny's Glossary of Growing & Gardening Terms

Familiarizing yourself with horticultural terms can help you better understand the different characteristics and needs of plants and methods for success in growing them. Whether out in the field, border, or raised bed or indoors under cover, knowing what these terms mean can also help you choose the best crops, varieties, and techniques for your setting.

  • Allelopathic : Term used to describe an organism, usually a plant, that has a biological effect on another organism through the production of one or more biochemicals that influence the germination, growth, survival, or reproduction of the other species. The effects of allelochemicals can be beneficial or detrimental.
  • Annual : A plant which completes its life cycle in one growing season.
  • Bare-root plant : Perennial plants that have been dug up and placed in storage, where they will partially dry out and go dormant, to be replanted the following growing season.
  • Biennial : A plant which lives for two years or seasons, having a life cycle that is two years or seasons in duration. Biennials generally flower and go to seed in the second season, using up the energy they stored during the first season, completing their life cycle.
  • Certified organic : Seeds harvested from, or plant material grown, harvested, stored, and handled under the guidelines required by the USDA's National Organic Program (NOP) and, more specifically, the laws enacted by the Code of Federal Regulations. Most of our organic part numbers have a "G" included with the part number.
  • Conventional : In the context of our product descriptions, conventional means not certified organic.
  • Cotyledon : The botanical term for the embryonic leaf in seed-bearing plants (angiosperms), one or more of which are the primary (first) leaves to emerge from a germinating seed. From the Greek cotyle, "small cup."
  • Cover crop : A crop grown to "cover" the soil and prevent erosion. These crops are grown after the primary crop is harvested. Fast-growing annuals are ideal choices.
  • Cultivar : An abbreviated term for "cultivated variety", a cultivar is a subset of a species that has been discovered, selected and/or developed by plant breeders. May be propagated vegetatively through layerings, cuttings, tissue culture, and so on. Some cultivars are patented (see also Plant Variety Protected definition.)
  • Grafted plant : Grafting is a horticultural technique used to join parts from two or more plants so that they functionally grow as a single plant. In grafting, the upper part (scion) of one plant grows on the root system (stock) of another plant. The grafted plant benefits from combined favorable characteristics of the rootstock, eg, hardiness, drought tolerance, generativity, or disease resistance, with those of the scion, e.g., flower and fruit set, appearance, flavor.
  • Grains : Small, hard, dry seeds harvested for multiuse purposes, including human consumption, animal consumption, and farm seed applications. Predominantly members of the grass family, but the term applies more broadly to include grain-like products such as buckwheat, quinoa, amaranth.
  • Green manure : A cover crop that can be used to replenish organic matter. Nutrients are released into the topsoil as the green manure decomposes. Green manures are often a mix of two or more types of seed.
  • Gynoecious : All (or virtually all) of the flowers produced are female.
  • Heirloom : Open-pollinated varieties whose seed lines have been maintained and passed down by gardeners and farmers over generations, prized for traits such as appearance, fragrance, and flavor.
  • Heritage : Varieties that deserve special recognition for having stood the test of time across the generations because of outstanding flavor, reliability, and wide adaptability. (As with heirlooms their heritage status has arisen not by chance, but unlike heirlooms, they are not necessarily open-pollinated varieties but may be hybrids developed through classical plant breeding methods. Note in some regions the definitions of heritage and hybrid may be interchangeable.) At Johnny's, we call these strains our heritage varieties because of their history and dependability as long-time favorites in the garden and on the farm.
  • Hybrid & (F1) hybrid : The offspring of a cross between two genetically distinct parent lines. Hybrid varieties are selected for traits such as improved flavor, disease resistance, fruit quality, yield, and climate adaptability. An (F1) hybrid refers to first filial or first-generation offspring of the cross. Seeds saved from an F1 hybrid will not produce plants with characteristics equivalent to the F1 hybrid.
  • Inoculant : Used to introduce beneficial bacteria to legume seeds prior to planting, to prompt and enhance conversion of atmospheric nitrogen to ammonia nitrogen within nitrogen-fixing nodules on legume plant roots.
  • Legumes : A family of plants grown agriculturally for many different purposes, including human consumption, animal consumption, and farm seed applications. Notable for ability to fix atmospheric nitrogen and accumulate it within root nodules via nitrogen-fixing, symbiotic Rhizobia bacteria.
  • Non-MT0 : Indicates that a seed product has not been tested for Lettuce Mosaic Virus. All items not tested have an "N" included with the part number.
  • NOP-compliant : When a substance or product is described as NOP-compliant, it means it has met all of the regulatory standards established by the USDA's National Organic Program.
  • Open-pollinated (OP) : A non-hybrid variety; one that can reproduce itself in kind, demonstrating relatively stable traits from one generation to the next. Seeds saved from OP varieties will produce plants very similar to their parents.
  • Parent Line : To create quality parent seed that is genetically stable, uniform, and perfect, a parent seed line with the desired characteristics is inbred for several generations. Two such parent lines are cross-bred to produce an F1 hybrid.
  • Parthenocarpic : In flowering plants, the female flowers are able to set fruit without pollination from male flowers.
  • Pelleting : Improves the shape, size, and uniformity of raw seeds for more accurate sowing by hand and machine. The pellets are made of clay-based, inert materials which don't harm the seeds or soil. As the pellets absorb moisture they dissolve, allowing immediate access to oxygen for fast, uniform seedling emergence. All pelleted products have a "P" included with the part number.
  • Perennial and tender perennial : A perennial is a plant that persists for more than 2 years.

    A tender perennial is one which is unable to survive the winter in a given particular growing zone unless given special protection or treatment, but which will, in its native habit, continue to live for more than 2 years. In growing zones where winter temperatures are lethal to the plant, it may be either treated as an annual — grown and enjoyed for a single season only — or alternatively, provided protection or treatment to mimic the conditions of the plant's native habit, to allow it to survive through the winter(s) into the following growing season(s). Examples of treatments to allow a tender perennial to survive include being heavily mulched, covered, and/or wrapped; or being dug up and stored until being sprouted or vegetatively propagated in late winter or early spring (e.g., saving Belgian endive roots for forcing for chicons; saving sweet potatoes and producing slips from the roots; taking cuttings of certain varieties of herbs to grow in containers).
  • Phytosanitary certificate : Documentation which satisfies a requirement by the Agricultural Departments of certain countries and states that the plant material is certified free of pests. There is a charge for this service.
  • Plant Variety Protected (PVP) : PVP status indicates that the breeder has the legal "right to exclude others from selling the variety, or offering it for sale, or reproducing it, or importing it, or exporting it, or using it in producing (as distinguished from developing) a hybrid or different variety." The term of protection runs 20 years from the certificate's date of issue, or 25 years in the case of a tree or vine. Unauthorized marketing of PVP seeds is prohibited. To learn more, see the USDA FAQ page on PVP.
  • Priming : A process whereby germination rate of seed is enhanced by expanding the temperature range at which it occurs, the speed at which it occurs, and in some cases, with additional priming, by breaking light dormancy. Many lettuce seeds, for example, are primed to enhance germination. The priming process does, however, shortern the storage life of the seeds. We recommend you purchase only enough primed seeds to last one season.
  • Resistant / resistance : Implies that a variety has a certain amount of resistance when exposed to a disease-causing pathogen such as a fungus, bacteria, or virus. The extent of resistance is displayed as either high (HR) or intermediate (IR).
  • Sets : Small, dry bulbs of allions (onions, leeks, shallots) for replanting.
  • Slips : A part, typically a piece of root or leaf or bud, removed from a plant to propagate a new plant through rooting, e.g., shoots grown from cuttings from mature sweet potatoes.
  • Smother crop : Used in new ground or in weed-infested soil to outcompete the weeds. Buckwheat is a common smother crop.
  • Tolerant / tolerance : Implies that a variety will perform relatively well when exposed to a particular environmental stressor such as cold weather, hot weather, or drought.
  • Treated : Seeds that have a coating of fungicide intended to protect them from rotting in the soil before germination. All treated products have a "T" included with the part numbers. Note: The seeds themselves should not be used for food, feed, or oil purposes.
  • Underseeding : The practice of using green manures as "living mulch." Corn is often underseeded with clover once the corn reaches 2 feet in height. Clover out-competes the weeds and provides a green manure after the corn is harvested.
  • Untreated : Seeds that have no chemical treatments. All seeds offered by Johnny's are untreated unless otherwise noted.
  • Variety : A genetically similar population of plants, distinct in one or more traits from other populations. Varieties do occur naturally and are found in nature.