A tap root is the thicker, dominant root of a plant, from which many other roots sprout.
A plant may be described as tender if it is sensitive to cold temperatures and frost. Tender perennials need to be moved indoors or to a greenhouse or cold frame over winter to protect them. They are unlikely to survive a British winter as they are often native to warmer countries.
A tendril can be a twining stem, leaves or petiole, that is used by climbing plants to attach themselves to other plants or surfaces and sometimes as a method of invasion by parasitic plants.
Thatch is a build up of dead organic matter on a lawn, which should be removed to allow greater water, nutrient and light penetration for grass to grow effectively.
Thin is a method used to improve the quality and growth of buds, flowers and seedlings, by removing some in order for the remainders to thrive.
This is a broken-down surface layer of soil that has been prepared for seeds to be sown.
Tip layering is a technique used to encourage new roots to grow, by burying the tip of a shoot in soil. It is particularly effective in brambles such as blackberries.
Adding a fertiliser such as compost or manure to the top of the surface of soil to act as a mulch.
Topiary is a popular horticultural practice where hedges and other plants are clipped into clearly defined shapes.
Topsoil is the top layer of soil, which is normally darker and more fertile than the soil underneath. Maintaining a good quality topsoil goes a long way to helping your garden plants.
How water moves through plants.
This is a common process of moving a plant from one area in your garden and planting it in another. You might do this for several reasons, but the most common is transplanting a seedling that has germinated indoors, outside to its final growing position.
Trellis is a fence with an open framework, typically used to support and display climbing plants.
A trowel is a small hand-tool used in the garden for digging.
A way to describe the first leaves that grow after cotyledon leaves. These leaves are usually different from the cotyledon leaves. See also, Cotyledon, Monocotyledon' and Dicotyledon.
A tuber is a swollen part of the root of a plant, which stores food for dormant plants. These tubers often have buds, or eyes from which a new plant can be grown, for example, potatoes.
Turf is a patch of grass which has been cut out from the ground, so it can be laid elsewhere. Usually turf comes in rolls which are then laid out to become a lawn.