Peat Moss – Garden Friend or Foe

BY Kathy Conner Cornell VCE Southside Master Gardener It is important to understand what peat moss is and the impact of harvesting it. Peat is made up of decomposed mosses and plants that slowly build up under cool and wet conditions. It takes hundreds of years to go through the decaying process to become peat. Peat bogs are being mined at a rate where we will potentially run out of peat within our lifetime and our kids lifetime. That is one issue. The second issue relates to carbon sequestration. Peat bogs store lots of CO2. When it is mined this carbon is released into the atmosphere. Carbon levels are rising and this adds to climate impacts. Peat bogs alone store one-third of the world’s soil carbon. Peat bogs make up 3% of earth’s surface but store 30% of land based carbon.
This is an example of the types of materials that go into a compost bin. Patience required while the materials break down. When crumbly brown humus forms, it is a great alternative to peat moss. The peat bog surface supports wildlife such as dragon flies, frogs and birds. Also, blueberries can be found in peat bogs that indigenous communities rely on. Here in the United States, our peat comes from Canada. The Canadian Sphagnum Peat Moss Association claims to be a sustainable harvester of peat. After harvesting it reseeds moss from nearby bogs thus putting in place a system to regrow the peat bog. Paul Short, president of CSPMA, admits that “we cannot replace the peat biomass that are removed from a bog in a human lifetime”. Linda Chalker Scott, an outspoken agent from Washington State Extension, says “A sustainable resource! Oh for peats sake. This is kind of like relying on the petroleum industry for the most objective information on the environmental effects of oil spills”. She suggests we use peat alternatives and eliminate peats use completely. What peat brings to the garden is an amendment that has strong water holding capacity but does not add much in the way of nutrients. It does add to the cation exchange capacity which holds nutrients to soil particles. But other amendments can perform this function. The following are sustainable alternatives to peat: Coconut coir is a by product of harvesting coconuts for oil, milk and shredded coconut. Larger fibers are used for doormats, brushes, rope and upholstery stuffing. Smaller fibers are used in the garden. It also has water retentive properties and adds to aeration. Wood based materials such as wood fiber, sawdust or composted bark can be used. Fresh sawdust can burn plants. Some municipalities process wood waste such as shrubs, trees and prunings to provide fine wood chips. We tend to think of this more as mulch than a soil amendment but these will break down over time and enrich the soil. Compost – compost is a DIY process that uses your kitchen scraps, grass clippings (although these feed the lawn if left on the grass) and yard waste. Do not compost weedy, diseased, infested or seed bearing waste. Compost adds nutrients and most importantly, is a source of microorganisms for the soil that are vital to plant processes. Pine needles – no need to worry that they will lower the pH. They decompose so slowly that this is a nonissue. Pine needles are readily accessible here in Southside. They support the idea of keeping within the sense of place since pines are so prevalent in our area. Leaf mold – this is an easy process whenever you have a bout of leaf drop. Place the leaves in a bin that provides aeration. Allow the leave to decompose for a year and you’ll have a nutrient source to amend the soil. This is easier and safer than burning the leaves which can cause harmful physical effects of the smoke byproducts. With as many deciduous trees as we have in Southside Virginia, there is plenty of ‘raw material’ for you to make your own natural fertilizer and soil amendment. Do not mix walnut leaves in your DIY composting that will be going into the vegetable garden, but can be used around many of our native plants. Just have patience in waiting for the composted leaf mold to break down. Composted manure - It is important to allow fresh manure time to breakdown. If you use fresh manure, it will burn plants. Composted manure adds beneficial microbes important for plant life. It increases water retention which is important for soils to increase their Carbon holding capacity. Hopefully this information will make you think before you pick up a bag of peat moss this spring. It should be noted that England has totally banned peat for homeowners use by 2020 and for commercial growers by 2030. The VCE Halifax Extension Office is now open. Masks and social distancing are required. If the door is locked, please knock. If you have gardening questions, you can continue to reach an Extension Master Gardener or Extension staff member by sending an email to or calling the Halifax Extension Master Gardener Help Desk at (434) 830-3383. Be sure to give us your first and last name, telephone number and the nature of the call. The Help Desk phone is routinely checked. Someone will get back to you, although it may be from a different telephone number. Remember the three W’s – wear a mask, watch your distance and wash your hands and consider an alternative source for peat moss this spring.