Heirloom

Heirloom varieties of vegetables or seeds are those that are open-pollinated rather than hybridized. Generally, the line must be 50-years old or older. These are seeds that are passed down from one farming generation to the next, hand collected, preserved, and cherished. They are the opposite of what you would find in a commercial agriculture farm where the plants are hybridized against common disease or have other characteristics that differentiate them from an heirloom seed or vegetable. 

GMO 

GMO seeds are laboratory created using techniques such as gene splicing under a process by which the DNA of the seed is modified. The process produces specific characteristics in the adult plant. GMO — plants are grown from modified GMO seeds. 

Non-GMO 

Non-GMO seeds are produced through open pollination. The wind or pollinating organism (honey bee) distributes pollen from one plant to the next resulting in the natural mixture of genes within the given gene pool. 

Hybrid 

A hybrid is a cross between two organisms - in this case, plants. When planted together in the same garden, one type of carrot and another type of carrot would produce hybrids - a cross between the two. GMO seeds are made in a lab. Hybrid seeds are the result of natural pollination among species of organisms that can crossbreed. Some hybrids are produced in a lab or controlled environment, but in general, a hybrid is produced through pollination rather than using science to splice genes. 

Organic 

Plants that are grown in an organic environment without the use of artificial growing agents. Organic chemicals may be used in organic gardens or farms but must meet the USDA system of organics; those chemicals must be approved. 
Different certification agencies: All certification agents must be certified via the USDA. These can include private, state, and governmental agents. 
Difference between certified organic seeds and seeds that can be used to grow certified organic vegetables. Certified organic seeds are grown and produced in an organic system - from a certified organic farm. Organic vegetables are grown in a certified organic garden or farm, and per the USDA, all certified organic farms must use certified organic seeds. 

Treated seeds 

Treated seeds are coated with a non-organic chemical or substance such as a pesticide, fungicide, either as a preventative to damage or as a preservative. 

Common Fertilizers 

Nitrogen, phosphorus, and potassium are the three most common fertilizers. Nitrogen is the primary form of fertilizer or energy that a plant needs. It helps with plant growth, the development of leaves, and more. Phosphorus is used at the plant cell level to increase photosynthesis and seed production. It also helps with root development. Potassium helps plants utilize nutrient uptake and the movement of nutrients through the plant's system. 

Soil PH 

pH is the measurement of acidity and alkalinity. Most plants prefer slightly acidic soil but not all. Understanding plants' soil pH requirements help you create a better growing environment where those plants may thrive.  

Perennial

A plant that lasts more than one year and is generally cold-hardy.

Determinate 

Determinate plants generally grow to a consistent height or size and then stop growing, produce their crop at one time — over a few weeks.

Indeterminate

Indeterminate plants tend to grow tall and vine until they die (tomatoes). Indeterminate plants also produce a continuous crop that ripens over the growing season. 

Direct sow 

The act of sowing seeds directly in the ground rather than starting them in containers or flats.

Pelleted seeds 

Commercial seed producers sell seeds by volume — weight — or by the number of seeds. A pelleted seed is a tiny seed coated in a substance so that it — the seed plus the coating - meets the standard sizing (weight or physical size) for the seed variety. 

Transplant 

The act of moving seedlings from one container to another or from a container to the final growing media or ground.

Pole/trellis 

Support structures that help plants grow vertically rather than allowing them to sprawl on the ground. Poles are single unit support structures that work well with vegetables such as pole beans. A pole works well with vegetables that do not have significant weight or that have a single stalk. A trellis is a multi-pole support system that supports the plant from the root to the crown and is perfect for use on plants with more weight or bulk. Peas work well on a pole, whereas cucumbers or melons need a trellis. Roses, cucumbers, tomatoes all benefit from a trellis. A cage, such as a tomato cage, is a form of trellis. 

Days-to-harvest 

The average number of days for a plant to produce a harvest-ready crop. The timing starts from when you plant the seed until when you pick or harvest the produce. Some families of vegetables, such as tomatoes, have varied days-to-harvest. For example, a beefsteak tomato may have 85 days to harvest, whereas a cherry tomato may have only 60 days to harvest. 

Soil Temperature

The temperature of the soil that is suitable for the specific plant. Cool-weather crops may germinate and thrive in soils as cool as 40°F. A tomato plant is a heat-loving plant and will thrive when the soil temperature is above 60°F or warmer. Plants may look healthy in soil that is too hot or too cold, but they undergo changes that stop root production, leaf production, and fruit development. Too hot or too cold may kill the plant. Soil temperate is different from ambient air temperature. When the weather is too warm, certain plants will bolt and go to seed. 

Fertilizing Teas 

Fertilizer comes in solid, pellet, and liquid forms. A newer variety is a liquid tea made by adding water to a dry product and then applied to the plant or soil. Teas are beneficial because they allow you to make only as much as you need. The varieties of fertilizing teas available will enable you to control the nutrient stream for different plant types. 

Parthenocarpy

The production of fruit without pollination.  This trait is particularly desire-able when normal pollination is difficult; e.g. when growing vegetables indoor where there is no wind or pollinator insects to assist with pollination.