Glossary- Gardening Terms

half hardy

A plant that needs to be protected from frost in order to survive year round.

hardening off

The process for introducing a plant, typically a seedling, to temperatures that are different from that which it is used to Normally refers to moving a plant from indoors to a cooler outdoors.

hardiness

The measure of how well a plant can survive in different climates and temperatures.

hardpan

A hard layer of soil that exists below a layer of topsoil. It is difficult to dig and typically, roots have a hard time growing through it and water does not penetrate through it.

hardwood cutting

A mature cutting that is rigid and woody that is taken from a parent tree in order to propagate the tree.

hardy

The ability of a plant to survive the local weather conditions year round.

haulms

The dried stems of a plant after the food from the plant has been harvested. Most commonly used to refer to the stems of potatoes after harvest.

heading back

A method of pruning plants in order to make them stronger and bushier. In trees, this can mean severely cutting back branches. In other plants, this can mean cutting off the top third of the plant.

heartwood

The center or “heart” of the trunk of the tree. This wood is more dense than the outer wood and is dead. It is typically denser than the outer wood.

heeling in

Temporarily planting a plant in order to protect its roots from the elements until it can be planted in a more permanent location.

heirloom

An open pollinated plant, normally a flower, vegetable or fruit, that has been cultivated for more than 50 years.

herb

A plant that has either culinary (cooking) or medical uses.

herbaceous

A plant that is non-woody and dies back to the ground in cold weather or during dormancy.

herbicide

A substance that kills plants.

high light plants

Indoor plants that need 5 or more hours of direct light to grow properly.

honeydew

A sweet, clear substance produced by aphids and some other pests. Many plant owners will notice the honeydew before they notice the pest infestation. This substance will also attract ants.

hummingbird gardening

Planting a garden designed to attract hummingbirds.

humus

The organic part of the soil. It typically occurs when plants and animals decompose.

hybrid

A variety of a plant that has been created through the cross breeding of two other varieties of that same species of plant.

hydroponic

Growing plants without soil and using nutrient rich water to support the needs of the plants.

hydroponics

The use of water and nutrients to grow plants without needing soil.

hypocotyl

The part of a seedling stem that is between the soil line and the cotyledon leaves.

hypogeal

Plants whose first leaves (cotyledons) first appear below the soil line during the seed germination process.