Important Common Plant Terms
Updated: Jan 8, 2021
This list is meant to be a glossary of gardening terms. It will be added to and revised on an ongoing basis, so check back often to learn more!
A plant that completes its life cycle in one year. Growing, flowering and producing seed all happens within one season.
A plant that continues to grow for more than one year. It may be a tree or shrub, where the woody stems stay erect throughout the winter or it may be a herbaceous perennial where the stems die back each winter and new sprouts emerge from the ground each spring. Plants may flower and produce seed every year or only later on in its life cycle. Plants may also be longer or shorter lived perennials, depending on the particular characteristics of its species.
A perennial plant that only lives for two years. These plants usually grow and produce leaves and roots the first year, then flower and produce seeds the second year. If you want to collect seed from biennial plants such as carrots and parsnips, you must let them continue to grow a second year.
What heirloom means can vary greatly depending on who you talk to, but the most widely accepted definition is a specific variety that has been grown since at least 1945. This is when modern/industrial agriculture is thought to have begun, right after World War II. Heritage varieties are heirloom varieties with some cultural significance attached to them.
The seeds that are produced when you use the pollen from two parents of the exact same variety of a species are open-pollinated varieties. This produces offspring that are exactly like the parents. If you want to save seeds, open pollinated varieties will give you reliable results. Allowing natural pollination (wind or insects) of these varieties will give you consistent results as long as each open pollinated variety is planted far enough away from the others. Most heirloom seeds are open pollinated.
Hybrid (F1, F2, etc)
The seeds that are produced when you use the pollen from two parents of different varieties of the same species are termed hybrids. This is done intentionally by plant breeders to select for offspring that have characteristics we like such as higher sugar content, earlier maturity or larger size. Seeds collected from hybrid plants will produce very different offspring and are therefore not good for seed saving.
GMO or GEO
Genetically modified or genetically engineered organisms have genetic material from a completely different species inserted into the genome of an organism. This can only be done in a laboratory. Controversy due to potential allergy concerns, toxicity, corporate ownership and questions of morality exist. However, there is also great potential for increased nutrition and ability to grow in very harsh environments to consider. Currently, the only GMO seeds produced for sale are cotton, alfalfa, papaya, corn and squash and most of these are only available to commercial farmers. As of this writing, the only GMO seeds a home gardener in North America can purchase are sold under the brand Seminis (a Monsanto company).
The farm where the seeds were grown has been certified as organic by national agricultural agencies. They have been grown without the use of synthetic chemicals, fertilizers, seed treatments, pesticides or herbicides. It is a certification that requires a number of years to obtain and can be quite costly. Be aware that many farmers are growing organically and are either in the process of getting certified or cannot currently afford certification.
Determinate and Indeterminate
Tomatoes, beans and some squash may be labelled as determinate or indeterminate types. This has to do with how they grow. Determinate plants are also known as bush type. They tend to be shorter and fruit all at one time. Indeterminate are also known as vining type. They can grow very tall and tend to fruit over a longer period. Knowing which type of seeds you have will help you decide if you need a 3 foot tomato cage or a 7 foot trellis. It will also help you decide the best way to prune your plants.
Small seeds are coated with a layer of clay or molasses to make them larger and easier to handle or to prevent clumping when using seeding equipment. Pelleted seeds require more moisture to ensure that water penetrates the coating all the way to the seed inside.
Seeds are coated with fungicides, insecticides or other pesticides to aid in germination or growth. They are often bright coloured. Note that some seeds may be both treated and pelleted.
Seeds are glued onto a decomposable length of paper at the precise spacing required for optimal growth. This is very handy for tiny seeds (looking at you carrots!) and saves time by doing away with thinning, however more water is required to keep the tape consistently moist for germination.
Physically damaging the seed coat in order to promote germination. This may be done by lightly crushing the seeds, rubbing them with sand paper or soaking them in water. Your seed package should give you instructions if scarification is required for your seeds.
The process of putting a seed through a cold cycle to mimic winter. Many seeds may require this before germination will occur. Seeds may be in soil or not and placed either in the refrigerator or freezer for a specific period of time. Your seed package should give you the details needed to germinate your particular seed if required.
The process of gradually making a plant use to outside light levels, wind, and temperatures to avoid transplant shock. The first day they are put outdoors in a shady spot for a few hours and then brought back inside. The second day they are left outside all day in a sunny spot and brought back inside at night. The third day they are left outside all day and night. The fourth day they are planted. Adjustments should be made for any extreme weather events such as rains or high winds.
Last Frost Date (LFD)
The average date that spring frost is last known to occur within a particular area or region. Note that this is an average and will vary from year to year. Also keep in mind that this date for a particular area may be different depending on the time frame used to determine the average. For example some people use the last 10 years, some use the last 100 years.
First Frost Date (FFD)
The average first date that frost is known to occur in fall within a particular area or region. Note that this is an average and will vary from year to year. Also keep in mind that this date for a particular area may be different depending on the time frame used to determine the average. For example some people use the last 10 years, some use the last 100 years.