- Tap root
- A thick central root attached directly to the crown of the plant that branches little if at all. A strong root, sometimes swollen, which grows vertically into the soil or compost.
- Tender
- An indoor plant which requires a minimum temperature of 60"F. Occasional short exposure to temperatures below this level may be
- Tendril
- A thread-like stem or leaf which clings to any nearby support.
- Terminal bud
- A plant's apical bud.
- Terrarium
- A partly or entirely closed glass container used to house a collection of indoor plants.
- Thatch
- The layer of dead stems that may build up beneath grasses and groundcovers resulting in reduced water and nutrient penetration.
- Thinning
- Pulling or clipping the weak seedlings in a pot or row in order to leave the others room enough to develop.
- Top dressing
- The application of fertilizer, whatever its form, to the surface of the soil around established plantings.
- Topiary
- The art of clipping and training woody plants to form geometric shapes or intricate patterns.
- Topping
- The detrimental practice of lopping off a tree at random locations on limbs and branches.
- Tree
- A woody plant with a distinct central trunk.
- Transplanting
- Moving a plant from one location to another.
- Transpiration
- The process of losing moisture by a plant, usually through its leaves.
- True leaves
- All the leaves that a plant produces above the seed leaves.
- Tuber
- An underground storage organ, part of either the stem or the root of the plant.
- Turgid
- Applied to cells and the plants which they comprise: fully charged with water. A damaging decrease in turgidity causes wilting.
