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Mulch is a protective layer of either organic or inorganic material that is spread on the topsoil to;
  • improve soil condition
  • act as barrier against pests
  • prevent rainfall and irrigation water from splashing soil borne pathogens onto the plants that cause plant diseases
  • prevent weed growth
  • provide home for earthworms and natural enemies found in the soil
  • retain soil moisture
  • reduce soil compaction from the impact of heavy rains
  • maintain a more even soil temperature
  • prevent soil erosion
  • Types of mulch

    1. Organic mulch

    Organic mulch helps improve the soil condition. It provides organic matter which helps keep the soil loose, as it slowly breaks down (decomposes). This improves the root growth, increases the infiltration of water, and also improves the soil water holding capacity. It is also a good source of plant nutrients and provides a better place for earthworms and other natural enemies found in the soil.

    Organic mulch includes cut grasses, leaves, straws, hays, bark chips, animal manures, seaweeds, corncobs, pieces of corn stalks, coffee berry pulps, saw dusts, old newspapers

    Amount to apply (thickness)
  • 2-3 inches for cut grasses
  • 2-4 inches for bark mulch and wood chips
  • 3-4 inches for compost and mold leaves
  • Œ inch for sheets of old newspapers for the control of weeds and to prevent thrips from reaching the soil to pupate. Cover lightly with other mulch materials to prevent paper from flying.

  • 2. Inorganic mulch

    Inorganic mulch is made of colored aluminized plastic and aluminum foil. The reflection from the sun confuses and repels the flying insects from coming onto the plants.

    To make you own reflective mulch, place strips of aluminum foil on both sides on the sown seeds or newly transplanted seedlings. Studies showed that red repels root maggots and other flies, orange on potato whiteflies, and blue reflection confuses winged aphids and thrips. Black plastic mulch discourages sawbugs and other crawling pests that cannot withstand the heat and keeps leafminers from emerging and prevents their return to the soil to pupate. However, you must do your own study as the pests from different regions react differently to various colors.

    Pest controlled

    1. Aphids
    2. Colorado potato beetle
    3. Leafminer
    4. Potato tuber worm
    5. Root maggots and other flies
    6. r
    7. Thrips
    8. Whiteflies
    9. Sawbugs and other crawling insects
    10. Soil borne pests that include insects/mites, weeds, and diseases


  • When mulching trees and other perennials, place mulch 1-2 inches away from the trunks and or main stems.
  • Monitor plants regularly to know the presence of slugs, snails, and mice. Mulch attracts these pests.
  • When mulching to control weeds, apply mulch immediately after soil cultivation/preparation to prevent sunlight from reaching weed seeds and the migrating seeds to settle in.

  • External links


    • Gilberg, L. editor. (1993): Garden pests and diseases. Sunset books. Sunset Publishing Corporation, California.
    • Olkowski, W.; Daar, S.; Olkowski, H. (1991): Common sense - pest control. The Taunton Press. USA.
    • Olkowski, W.; Daar, S.; Olkowski, H. (1995): The gardener?s guide to common-sense pest control. The Taunton Press. USA.

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