County of Orange Greeneries

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Sprout coming up from soil with the sun shining

 

Thank you for your interest in the County of Orange Greeneries. Below are tips and information regarding our STA Certified compost and mulch offerings available by request. Follow us on social media @OCWaste for future giveaway events.

 

COMPOST VERSUS MULCH

COMPOST 2
MULCH 3

Compost

Compost is typically used as a soil amendment, but may also provide plant nutrients. Finished compost is typically finer than mulch and screened to reduce its particle size, to improve soil incorporation.

Mulch

Mulch is compost of a coarser particle size, containing a larger percentage of composted wood particles. It is commonly used on the surface of the soil and helps retain water in the summer and adsorb more rainwater in winter.

HOW TO USE OUR COMPOST

  • TREE AND SHRUB CLASS
person gardening a tree

Establishment

Excavate a planting hole slightly shallower and 2 to 3 times the width of the root ball or container.  Set the root ball on firm soil so that the top of the root ball sits slightly higher than the final grade.  Uniformly blend compost with the excavated soil at one (1) part by volume to 2-3 parts by volume soil.  Compost with higher amounts of salts and nutrients should be used at lower rates (e.g. 1:3 or 1:4 parts compost to soil).  Backfill and firm the soil blend around the root ball within the planting hole.  Always water thoroughly after planting.  It should be noted that whenever possible, trees and shrubs should be planted in a mass planting bed, where multiple plants are established in a larger amended bed.  This technique allows for greater planting success.

Lower compost application rates should be used for salt sensitive crops (e.g., conifers), or where composts possessing higher salt and nutrient levels are used, while higher application rates may be used for plants that require greater amounts of fertility.

Maintenance:

Apply a coarser compost mulch (1’’ – 2’’ screened) over the garden bed to conserve moisture, for weed suppression and/or for aesthetic purposes.  Note: The nutrients contained in compost should be considered when applying fertilization.  They will typically offset plant nutrient requirements, thereby potentially reducing fertilizer application rates. 

 

  • FLOWER AND VEGETABLE GARDEN

birds eye view of person gardening

Establishment:

Compost should be uniformly applied over the entire area at an average depth of 1-2 inches and then incorporated to a depth of 6-8 inches using a rotatory tiller or other similar equipment.  Higher application rates of compost may be used if the compost is incorporated into a greater depth.  Rake the soil surface smooth prior to seeding or planting.  The soil should be free of large clods, roots, stones, and other material that will interfere with planting.  The amended area should be watered thoroughly after planting.

Lower compost application rates may be necessary for salt sensitive crops (e.g., strawberries), or where composts possessing higher salt and nutrient levels are used, while higher application rates may be used for plants that require greater amounts of fertility (e.g., tomatoes).

Maintenance:

Apply a coarser compost mulch (1’’ – 2’’ screened) over the garden bed to conserve moisture, for weed suppression and/or for aesthetic purposes.  Note: The nutrients contained in compost should be considered when applying fertilization.  They will typically offset plant nutrient requirements, thereby potentially reducing fertilizer application rates. 

  • TOP DRESSING

wagon full of topdressing for the garden

Topdressing is a method of applying compost by spreading a thin layer on top of your project area. With this surface application method, established plant roots aren’t disturbed.  Make sure not to pile compost against the crown of the plants, as this holds water on the stems of plants.  Worms and rain help mix the compost into the soil.  Generally, the compost is spread 1-2” thick around trees, shrubs, flowers, and vegetables.  On top of lawns, a finer grade compost is spread 1/4 - 1/2" thick.

  • INCORPORATE INTO SOIL

As its name suggests, this method involves mixing compost into the soil as an amendment. This is an especially useful method when the soil is compacted or lacks organic matter, and there aren’t tree roots to avoid.  Generally, the compost is applied 1-2” thick and then mixed in 6-8” deep into the soil.

  • ADD TO TOPSOIL MIX

As part of this method, the compost is added to topsoil mix and then applied to your project area. This method is necessary when more bulk volume is required for the project.  A ratio of 20-30% compost to 70-80% subsoil is recommended to create new topsoil. The goal is creating soil with 5% organic matter (OM), measured on a dry weight basis.

person holding small garden shovel scooping topsoil

*Instructions for use per the U.S. Compost Council

 

LOCATIONS & COMPOST AVAILABILITY

The County of Orange operates Greeneries at our landfill sites. Our Greeneries play an integral part of the growing regional resource recovery infrastructure to support state mandated recycling of organic waste.  By recycling organics such as curbside green waste, we preserve valuable landfill space and support the region in meeting key recycling targets to reduce greenhouse gas emissions.  We repurpose these materials into beneficial products such as mulch and STA Certified compost, available for residential and community use. Locations include:

  • Bee Canyon Greenery, 11002 Bee Canyon Access Rd., Irvine
  • Capistrano Greenery, 32250 Avenida La Pata, San Juan Capistrano
  • Valencia Greenery, 1942 N. Valencia Ave., Brea – COMING SOON -- EARLY 2023

For more information on how to obtain compost and mulch, click here. For additional questions, call 714-834-4000.