Horticultural fleece is a thin, unwoven, polypropylene

Polypropylene

Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...

 fabric that is used as a floating mulch

Mulch

In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....

 to protect early crops and other delicate plants from cold weather, frost, and insect pests. It admits light, air and rain but creates a microclimate

Microclimate

A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet or as large as many square miles...

 around the developing plants, allowing them to grow faster than unprotected crops.

Method of use

Available in rolls of various widths, fleece is laid out across the sown seedbed or young growing plants. The edges are either pegged down (if the site is small, or not too exposed to winds) or buried in slit trenches. It will stretch slightly in use, allowing the plants to grow. For taller plants grown in rows or blocks, heavy-duty fleece can be used to create cloche

Row cover

In horticulture, row cover is any material used as a protective covering to shield plants, usually vegetables, primarily from the undesirable effects of cold and wind, and also from insect damage....

s. When used as winter protection the fleece is wrapped around, or fastened over, delicate plants, to protect them from frost and scorching by cold winds.

Uses

• Extending the growing season for vegetables by allowing earlier sowings in spring and later cropping in autumn
• Hardening-off
  Cold hardening
  Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather.-Plants:During the winter months, as the leaves fall off deciduous species and the temperature drops, the cold forces a stop to water movement in plants. Freezing water can also cause...
  
   seedlings before transplanting
  Transplanting
  For botanical organ transplant, see GraftingIn agriculture and gardening, transplanting or replanting is the technique of moving a plant from one location to another. Most often this takes the form of starting a plant from seed in optimal conditions, such as in a greenhouse or protected nursery...
  
   them
• Protecting winter crops, allowing them to produce softer, more palatable growth than unprotected plants
• Providing extra warmth for crops of borderline hardiness
• Winter protection for ornamental plants and fruit blossom
• Protection from pests such as pigeons, rabbits, carrot fly
  Carrot fly
  The carrot fly is a pest of gardens and farms, and mainly affects the crop of carrots, but can also attack parsnips, parsley and celery.It is a member of the family Psilidae .-Larvae:...
  
  , Small White and Large White
  Large White
  The Large White , also called Cabbage Butterfly, Cabbage White, or in India the Large Cabbage White, White cabbage butterfly is a butterfly in the family Pieridae.-Distribution:...
  
  butterflies etc.