Composting Basics

What is Compost? Composting is the process of breaking down organic matter, and the elements and nutrients retained in it, back to a chemical state where it is again available for plants to use

What Does Compost do for Soil? Increase water and nutrient holding capacity Balance pH (buffering) Food for soil organisms and slow release nutrients for plants Improves soil structure

Nutritious soil for healthy plants

Essential Components of a Composting System Organic matter- C:N 30:1 (Plant and animal matter and manure) Water- 40-60% Oxygen (large pore space allows for more gas exchange) *You are creating an environment for the decomposers to work their magic

Carbon:Nitrogen ratio C:N Greens: Mostly nitrogen Carbon:Nitrogen ratio C:N Greens: Mostly nitrogen. Fresh, moist, likely to get smelly Browns: Mostly carbon. Old, dry, no noticeable smell Greens C:N ratio Browns C:N ratio Horse manure 18:1 Dry garden waste 40:1 Cow manure 16:1 Leaves 60:1 Chicken manure 12:1 Straw 75:1 Grass clippings 20:1 Hay Kitchen waste 25:1 Wood chips 400:1 Fresh garden waste 30:1 Paper 150:1 Coffee grounds   Urine 1:1

Water and Oxygen Water Necessary for life 40-60% usually ideal in compost As wet as a wrung out sponge Coarser textured compost can hold more water Too wet will reduce oxygen levels Oxygen Aerobic decomposition is ideal Faster, higher quality product Less off gassing of nitrogen Better smell

Ways to Compost Hot Passive

Passive Composting: A slow, cool decomposition process mainly mediated by fungi and secondary decomposers such as springtails, sow bugs, earthworms and nematodes Easy Takes time Does not kill weed seeds and pathogens

Passive Compost Rings

Passive Compost: Rings

Passive Compost: Rings and Bins Photos courtesy of Dr. Mack Thetford. Homeowner compost rings and compost bins at Press Street Gardens

Passive Compost: Turning Bins

Red Worm Composting Redworms in bins, are fed compost and garden scraps (vermiculture) Worms digest the compost and excrete soil (worm castings)

Vermiculture: Red Worm Composting Redworms are surface feeders that consume and break down a wide range of kitchen waste and greens Avoid feeding: meat, citrus, dairy, oils Feed top of pile Cover with damp and fluffed newspaper or other bedding materials Keep moist and cool (below 84°F is ideal) Allow for drainage Screen or barrier to avoid mass exodus Infamous denitrifiers (nitrous oxide evolution) Do not expect “castings” to be a fertilizer Great addition to potting soil, or garden soil amendment

Hot Composting: Higher energy input Short time,as fast as 18 days Fast, high temperature decomposition process mainly mediated by bacteria, actinobacteria, and fungi Higher energy input Short time,as fast as 18 days for initial breakdown Kills weed seeds and pathogens More nitrogen conserved

Hot Composting

ECUA: Bloom Yard waste and biosolids Composted at high temperatures High quality standard Inexpensive Environmentally friendly Safe

What to do with compost? Top dressing of compost Top dress around perennials, trees and shrubs Incorporate into soil before planting Can you use too much? Compaction, drainage issues Nutrients will leach into soil and be incorporated by soil organisms over time Top dressing of compost Incorporation of compost into soil

Plants respond to compost!

Camellias like compost too Camellias thrive is slightly acidic and well drained soil Top dress plants with compost avoiding mounding compost close to the trunk Slow release plant food Cools soil Helps manage moisture

Questions?