- Scarification
- The nicking, sanding, or otherwise compromising the hard outer coating of seeds to increase their water intake and thus promote quick germination.
- Seed
- A fertilized, ripened ovule, almost always covered with a protective coating and contained in a fruit.
- Seed leaves
- The first two leaves - sometimes only one leaf - that grow after germination.
- Seedling
- A very young plant that's been started from seed.
- Semi-evergreen
- Retaining at least some green foliage well into the winter, or shedding leaves only in cold climates.
- Sepal
- One of the outermost series of flower parts, arranged in a ring outside the petals, and usually green and leaflike.
- Setting
- The development of seeds or fruit after pollination.
- Setting out
- Transplanting a seedling into the open garden.
- Scale
- An insect with a waxy shell-like covering that camouflages and protects it from enemies and insecticides. It destroys plants by sucking the plants juices.
- Shade
- A reduced amount of sunlight. Light shade usually refers to a few hours of morning or late afternoon sun, but considerable skylight all day long. Moderate shade is filtered light as that coming through trees with light foliage, but little or no direct sun at anytime. Heavy shade is that under trees with thick foliage, and is suitable for only a few plant species.
- Shearing
- Wholesale cutting back of a plant, rather than selective pruning or deadheading. Often used to regenerate plants with many, small stems, where deadheading would be too time consuming.
- Sheet Composting
- A method of spreading undecomposed organic materials over the soil's surface, then working them into the soil to decompose, rather than piling them and spreading the resulting compost. (see also Green Manure).
- Shrub
- A woody plant with a framework of branches and little or no central stem.
- Slip
- A herbaceous soft-wood cutting used in propagation.
- Slugs
- Snails without a shell, they feed on plants by biting tissue with rasping mouths underneath their bodies.
- Soilless mix
- Any potting mix that is made without the addition of soil. Some common components include peat, bark, coconut fiber, vermiculite, perlite and sand.
- Soil polymers
- Super absorbent polymers recently developed that can increase water retention of soils. They can absorb hundreds of time their weight in water and are primarily used in container bound plants.
- Soil test
- An analysis of the soil used to diagnose soil type, pH, and any nutrient deficiencies that may exist. Can be done by commercial soil laboratories or your local cooperative extension. Some nurseries have soil-test kits available that can indicate certain specific problems.
- Sphagnum moss
- Various mosses native to bogs are sphagnum.
- Spike
- An elongated flower cluster; individual flowers lack stalks.
- Spinnerets The fingerlike protruberances on spiders' posterior abdomens (rear-ends) that are used to extrude web silk.
- Spore
- A reproductive cell of nonflowering plants, such as ferns.
- Stem
- A branch of a cane, emerging from a bud eye and bearing leaves and at least one flower.
- Stopping
- The removal of the growing tip of a plant to induce the production of sideshoots or the formation of flower heads. Also known as "pinching out".
- Stratification
- The storage of seeds in warm or cold conditions to break dormancy and aid germination.
- Succulent
- A plant with thick, fleshy leaves or stems that contain abundant water-storage tissue. Cacti are an example.
- Sucker
- A shoot which arises from an underground shoot or root of a plant.
- Sulfur
- A mineral element that has fungicidal properties. Sulfur dust is used to prevent many fungal diseases, and also functions as a minor nutrient for plants.
- Systemic
- Chemicals that a plant absorbs which then permeate it. Certain insecticides, herbicides, and fungicides are systemic.
