Health and Wellness

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Recycle! Organics and Composting

Waste Reduction, Recycling, and Enforcement

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All About Composting 

What is Composting?

Composting is a natural process that recycles leaves, grass clippings, and small twigs into rich organic matter. Composting returns organic matter to the earth for reuse; and compost is one of nature’s best mulches. It can benefit even the smallest yard or garden and can be used around trees, shrubs, and in planter boxes.

Because it is easily turned into a resource, yard waste is banned from landfill disposal and, therefore, cannot be disposed of with regular trash. Residents have three options to manage their yard waste:

1. Subscribe for yard waste collection through their trash hauler or municipality;
2. Take yard waste directly to a commercial composting facility where it is composted (fees vary by facility);
3. Compost the yard waste in their own backyard.

How Can I Compost?

The breaking down of organic matter is a cycle that occurs in nature without any human intervention. When you compost in your backyard, the goal is to provide a satisfactory environment for nature’s decomposers (bacteria, fungi, and invertebrates) to do their work. Composting can be done actively, with frequent turning, or passively, with little to no turning. Active piles break down faster, but the basics for both methods are the same.


Choose a level area in your backyard with good water drainage – partially shaded is best. The availability of water is a plus. Compost bins are not necessary to make good compost, but they help. You can simply rake your compost ingredients into a mound. The key is to keep the pile large enough to hold heat (at least 3’ x 3’ x 3’) but small enough for air to reach the center (no more than 5’ x 5’, but it can be any length).


For best results, compost should contain alternating layers of “green” and “brown” plant matter. Brown materials provide carbon to the pile and consist of dried leaves, small twigs, wood chips, and straw. Green materials provide nitrogen and include grass, flowers and stems, and fresh plant trimmings.

When composting, do NOT use:

  1. Meat, grease, or dairy products;
  2. Weeds that have gone to seed;
  3. Diseased or infected plants;
  4. Animal waste.


Compost piles need watering or they will become dormant; however, too much water can cause odors. In general, keep the pile as moist as a damp sponge. It is best to water the materials as you add them.


If choosing to maintain an active compost pile, the most effective way to determine when to turn the pile is by monitoring pile temperature. The pile should be turned whenever there is a substantial decrease in heat. A simpler method is to turn the pile five to ten days after new material is added (a pile will benefit by turning, but it is not essential). You can also use a broomstick or a pitchfork to poke holes in the pile to allow air in.

Finished Compost

The compost is “finished” when it is dark and crumbly and the materials are no longer recognizable. The compost can now be used as a soil amendment, mulch, or as a seed starting mix.


The Saint Louis County Waste Code requires backyard compost piles to comply with the following:

1. It must be managed to prevent the harborage of rodents and pests.
2. It must be maintained to prevent odors.
3. Meat scraps, bones, fatty foods, and pet feces are not permitted in a residential compost pile.
4. It must be located at least three (3) feet behind the front of the main residential structure.
Composting 2
5. It must be located to prevent leachate (the water that has come in contact with the compost) from flowing onto adjacent property or into natural or human-made storm channels.
6. Compost piles abutting adjacent properties must not be visible from adjacent property (shielded from view by shrubbery or an enclosure).
7. Composting enclosures must comply with all local zoning regulations.


Composting is easy, but there are some common problems that can be avoided. The following table is a simple guide to keep your pile “breaking it down”!

Composting Trouble-Shooting Guide
Symptom Problem Solution
The compost has a bad odor. There is not enough air. Turn it.
The center of the pile is dry. There is not enough water. Moisten the pile while turning it.
Pile is damp and warm in the middle but nowhere else. The pile is too small. Collect more material and mix the old into a new pile.
The pile is damp and sweet smelling but it won’t heat up. The pile lacks nitrogen. Add green material.

To learn more about composting, visit the Missouri Department of Natural Resources’ website: Homeowners' Composting Guide, How to Manage Yard Waste

The Saint Louis County Health Department also offers free composting classes for groups of ten or more. Please call (314) 615-8958 for details.

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Grass Cycling - "Mulch" Easier than Bagging

A healthy lawn and grass cycling go hand in hand! Do your back and your lawn a favor and kick the bagging habit! (Some people may refer to it as “grass recycling”, but the proper term is “grass cycling”.)

Grass clippings are a valuable source of nitrogen-rich organic matter. When mowing, remove no more than one-third of the total plant height so that the clippings are small enough to sift back down into the turf and break down quickly, thus returning valuable nutrients back to the soil. Using a mulching lawn mower or simply converting your existing mower with a mulching attachment is an easy way to practice grass cycling.

Mulching your grass clippings does not cause thatch! Thatch is a layer of living and dead organic matter that occurs between the green matter and the soil surface. It is actually the tough fibrous part of the grass stem (which takes much longer to decompose) that contributes to thatch buildup. However, clippings are very high in water content and break down rapidly when returned to the lawn after mowing (assuming the lawn is mowed regularly and that no more than one-third of the leaf blade is being removed during mowing).