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01 • 02 • 2010

Composting: Worms, Bins and Tea

By Surfrider Foundation

Compost helps kick start the transition from dirt to healthy soil, providing water, oxygen, nutrients, and essential microbes. Once the plants grow, their own leaf litter and root systems can act as self-made mulch and compost. Compost itself is pre-decomposed organic matter through the use of heat piles and/or carefully selected and fed microorganisms and worms.

The Benefits of Composting

This natural source of healthy soil can feed your plants without the need for chemical fertilizers, which pollute our local waterways, kill important soil biology and release greenhouse gas emissions. Composting also helps divert food waste that otherwise would go to the landfill and emit methane- one of the world’s most powerful greenhouse gas emissions that fuels climate change. Not to mention, composting helps us feel more connected to the earth, our plants, and the soil cycle.

A Note on Fertilizers

The nutrient-rich water running off fertilized residential properties poses a significant threat to the health of our ocean. Primarily composed of nitrogen, phosphorus, potassium, and iron this runoff causes the rapid growth of harmful algae. Organic fertilizers are promoted over chemicals, because they build the soil, rather than degrading it, which in turn increases porosity and the ability of the landscape to hold more rain water - all of which decreases the chances of run-off.


Types of Composting

There are three main types of backyard composting:

  1. Vermiculture (also known as worm bin) which uses red wigglers to breakdown raw foods, cardboard, paper and leaves.
  2. Compost bins which use heat and moisture to breakdown raw foods, cardboard, paper and leaves.
  3. Compost piles which mainly use heat to breakdown materials.

What Can be Composted

The following comes from Surfrider Foundation’s Ocean Friendly Gardens book, Chapter 13:

“Aquarium Water: Straight from the fish tank to the garden, aquarium water is high in nitrogen and phosphorus.

Catch / Infiltration Basin Sludge: Catch basins and retention areas will eventually fill with sediment and debris, and will need to be cleaned out. This sediment is loaded with a variety of nutrients and can either be mixed right into planter beds or added to a compost pile or bin.

Coffee Grounds: This abundant and often-discarded resource is a good source of nitrogen and can be used as light mulch. When added to compost piles, coffee grounds also help produce nitrogen-rich humus. If asked, local coffee houses will typically give a customer their used grounds. If using for a vermiculture system, be sure to balance the PH by also adding crushed eggshells.

Eggshells: Containing a large amount of calcium and moderate amount of nitrogen, eggshells can either be scattered directly over a landscape, or put in a compost pile, bin or vermiculture system.

Feathers: While not an abundant resource unless there is a bird in a house, or the property has a cat, feathers are an excellent source of nitrogen. This resource should be composted by adding to a bin or pile.

Grass Clippings: The debris created from mowing a lawn is a perfect high-nitrogen fertilizer if it is cured in a compost pile, bin or vermiculture system first. Scattering freshly cut grass over soil does not work as well, because if it is not kept moist then the sun will chemically break them down and they will be blown off the property; on the other hand, if the clippings are kept too moist, they may produce an acidic barrier on top of the soil.

Hair: Human and pet hair is rich in iron, manganese, and sulphur. Hair is best used as an additive in a compost pile, but when used as mulch it can help deter larger pests, such as some rodents and birds.

Kitchen Scraps: Kitchen scraps of vegetables and fruits make some of the richest composts. Kitchen scraps are fleshy, moist, and loaded with nutrients, which speeds the decomposition process and time required to turn the scraps into compost and humus. Tea bags, coffee grounds, crushed and dry dog food, and eggshells can be thrown into this mix. These high-activity compost piles do not require a lot of room, just an area comparable to an old bathtub; yet they provide an excellent source of readily available nutrients. Kitchen scraps are typically high in phosphorus and potassium, but low in nitrogen (unlike animal products).

Pine Needles: An abundant resource in many landscapes, pine needles belong in a compost pile, or used as a mulch to deter weeds. Needles are low in nitrogen, phosphorus and potassium.

Tea Grounds: An abundant resource in many homes and coffee houses. Tea grounds have a moderate amount of nitrogen and low amounts of phosphorus and potassium. This resource should be composted.

Wood Ashes: Completely cooled and dispersed straight from the fireplace to the garden beds, wood ashes are high in potassium, with minor amounts of phosphorus, which is perfect for flowering and fruiting plants. Ashes are a good addition to the compost pile.”

Compost Tea

From OFG book, Chapter 13: “Compost Tea: An organic concoction that concentrates nutrients in a liquid form. Useful in overcoming degraded areas and supporting productive landscapes. Tea is made by filling a permeable bag, like nylon stocking or burlap bag, with compost (generally made from worm castings, manures, and/or grass clippings) and setting the bag in a large bucket of water. The tea takes frequent stirring, or mechanical aeration, and about 2 days of seeping.” Click here to learn more about compost tea makers from the company, Keep It Simple.

Grow a Green Manure Crop

From the OFG book, Chapter 6: “Sow Green Manure: There are a variety of plants that are particularly good at improving degraded soils, called green manures. These plants include those that can fixate nitrogen, like clover and vetch, and those that are tough and vigorous, such as alfalfa, millet and rye. These plants are seeded and once they have a hold of landscape they are tilled into the soil and allowed to decompose. The area will be ready for planting 3 months after tilling.”

Composting Resources

Workshops- many cities and garden centers provide free or low cost compost workshops, e.g. City of Los Angeles

Surfrider's How To Build Your Own Compost Worm Bin

Surfider's Healthy Soils article

EPA's Composting at Home