NOVELTY - Preparation of garden flame retardant organic mulch includes taking branches, leaves, stem and leaves from garden waste, combining leaves and flower stems, removing mixed iron wire, rock, rubber and tree pile; pulverizing branches, shredding leaves and flowers, mixing, storing; adding fermentation strain, chicken manure and urea, regulating carbon and nitrogen, piling in greenhouse space, stacking, watering to saturation, pulling pile body upper layer particle, watering to saturation, re-pulling cover of particulate matter in source stack body, fermenting, and keeping ventilation.    USE - Method for preparing garden flame retardant organic mulch (claimed).    ADVANTAGE - The method recycles garbage for garden use, reduces dust, maintains soil humidity to prevent soil plate, inhibits weed growth, enhances soil fertility, and improves landscape.    DETAILED DESCRIPTION - Preparation of garden flame retardant organic mulch comprises taking 30 cm branches, leaves, stem and leaves from garden waste, independently classifying branches, combining leaves and flower stems, removing mixed iron wire, rock, rubber and tree pile; pulverizing branches into 1.5-7.0 cm particles, shredding leaves and flowers to less than 0.5 cm fine particles, mixing, storing; adding 1-1.2 kg fermentation strain, 25-30 kg chicken manure and 12.5-15 kg urea per 1-2 tons or 5 m3 raw material, regulating carbon and nitrogen to a ratio of 30:1-1.5, piling in greenhouse space height of greater than or equal to 4 m, stacking to 1.3-2 m high, watering to saturation for 2-3 days, pulling pile body upper layer particle to 50 cm thickness, watering to saturation for 2 days, re-pulling cover of particulate matter in source stack body, fermenting for 30-45 days, keeping ventilation and stacking water content, adjusting stack temperature to 55-65 degrees C using auxiliary ventilating and manual forklift periodically, turning once every two weeks in spring and autumn seasons, and once every ten days during summer, turning for the third time without water or only adding a small amount of water; layering organic mulch to a thickness of 5-8 cm, covering base to keep circular edges of tree base at a distance of 20-30 cm; taking solid ammonium polyphosphate and water, mixing into a solution, and spraying on surface of mulch at a permeation depth of 3-5 cm. The mass ratio of ammonium polyphosphate and water is 15-20:100.