Article

Alternative uses for sawdust, a renewable natural resource

Sawdust, a byproduct or residue from the milling industry is often overlooked as a resource in many industries such as horticulture, agriculture and landscaping. With proper use and management, there are many valuable uses for sawdust and in most cases is a much more cost-effective solution.

Agriculture

Spread on your paddocks

Sawdust application on paddocks can reduce nitrogen leaching in our waterways. Its high absorbency acts as a sponge for nitrates from urine, fertilisers, and other excretions.

Sawdust is a carbon-based material. To decompose, it needs the help of nitrogen. The nitrogen comes from the soil or compost around it, which is why it is great for agriculture paddocks where nitrogen is released at an extremely high and toxic rate.

However, sawdust doesn’t keep this nitrogen forever. It uses nitrogen to help break down and work its way into the soil as organic matter. During this process, the sawdust slowly releases nitrogen at a controlled rate, which the soil and plants around it are able to use as nutrients. This prevents leaching into our waterways in large quantities that the soil cannot handle on its own.

Benefits of applying sawdust to your paddocks:

✓ Increase organic matter to help grass grow

✓ Reduce mud for better animal welfare

✓ A natural sponge that absorbs nitrogen

Sawdust specifications

Sawdust as Animal bedding

Sawdust make an absorbent bedding option that is readily available and relatively easy to sweep up. The small particles are great for indoor use to provide a cushiony warm layer. Blending with other wood products is also an option if you are needing larger particle sizes.

Animal bedding benefits include:

Used as a flooring material
Comfort for animal
Encourages resting
Contribute to udder health
Contributes to milk quantity & quality
Minimizes injury and fatigue

Improve vineyard soil with Azwood compost

Horticulture

Improve vineyard/orchard soils

Sawdust can help to increase Mycorrhizal fungi and mycelium which serve important roles in our soils. They increase the surface area of roots through their symbiotic relationship with plants, helping to access water and essential nutrients. This in turn enhances plant growth and increases production.

Some consider sawdust to be one of the best solutions for improving clay soils. Sawdust breaks down slowly, so it is a longer-lasting soil amendment than many other available options.

Note - It takes time to improve soil health so multiple applications are recommended to get the best result.

Sawdust specifications

Line walkways between produce fields

Sawdust makes a very good material for lining paths and walkways. It is soft underfoot and will compress and compact, which will help to keep it in its place.

✓ Compresses over time

✓ Suppresses weeds

✓ Reduces soil erosion and mud

Mix sawdust with compost

Bulks it up/ builds volume
Provides more air pockets to help bring oxygen to compost which is an essential part of the decomposing process
Good source of carbon and/or carbohydrates, which are the food source for microorganisms.
Put back into our soils to increase plant health - see the long-term benefits

Landscaping

Mulching

All the benefits of mulch without the high price tag. Sawdust works in a similar way to mulch by holding moisture, suppressing weeds and cooling plant roots. Just be sure to add a nitrogen component to your garden as well, in order to prevent nitrogen deficiency in the soil.

Benefits of sawdust in gardens:

Increase the presence of beneficial soil fungi like mycorrhizae which promotes plant health
Cheaper than normal mulch
Protects sensitive plants and helps trap moisture in the soil

It’s ironic in some ways that sawdust can be considered a weed killer because it is an excellent soil amendment that can help plants grow, too. It’s all in how you use it.

Counteracting nitrogen loss in the garden

Add nitrogen fertilizer. Some recommended options include compost, composted manure, ammonium nitrate, or ammonium sulphate.

Compost the sawdust completely before use, at which point it will no longer need to use the nitrogen in your soil.

Apply sawdust amendments directly to the garden at the end of a growing season when it will have many months of garden dormancy to break down. A fall application that overwinters in or on the garden, for example, is ideal.

Use in small amounts and applied at more frequent intervals so that the demands on available nitrogen are less.

It’s worth repeating that the nitrogen used by sawdust decomposition is not a permanent loss of nitrogen in the soil, it’s just unavailable for a while, while the sawdust uses it. Think of the nitrogen as locked and unavailable, not gone completely. Once the sawdust has completed its decomposition, nitrogen is slowly returned back to the soil, meaning it will be rich with nutrients for your plants once again.

Acid-loving plants love sawdust

Regular application can help keep the acidity levels of soils higher, which will enhance the growth and production of these plants. The release of acid from sawdust occurs mostly early on in its decomposition.

Uses:

Grow mushrooms, potatoes and tomatoes directly in sawdust.
Mix with compost for correct application
Plants classified as ‘acid loving’ thrive in acid soils and include trees and shrubs with a variety of shapes, foliage and flowers.

Other uses for sawdust

Burn it

The main component of wood pellet fuel is Sawdust, you may already be utilising it in high energy pellet fuel for your pellet fire. This can be for commercial use or just in a regular pellet fire in a home.

Although wood releases carbon when it is burned, this is offset by the carbon which is absorbed when a tree is grown making it carbon neutral and more environmentally friendly than fossil fuels.

With NZ moving towards a carbon-zero future with most gas and log burners being phased out, this is a great solution to use a renewable and sustainable energy source.

Pros of pellet fuel:

Carbon neutral energy source. No smoke only produces steam.
Some have timer options to pre-warm your home.
Can ignite with the press of a button.
Traditional burn of a log fire.
Back up options in power cuts.
You can purchase pellet fuel as needed all year round

More information on wood energy

Clean up spills

Due to its high absorbency, sawdust is great to have on hand to soak up spills.

Road grip in winter

Winter road operations can spread sawdust on their truck paths or roads instead of salt. Sawdust provides traction while protecting the ground underneath. Salt is more harmful when it drains into our waterways so this option is much more environmentally friendly as sawdust decomposes over time.

When not to use Sawdust

01
On acid-sensitive plants (decomposing sawdust does release a flush of acid, too, which can affect soil pH)
02
The sawdust from black walnut trees should be avoided for most garden growing purposes. This is due to the presence of juglone, a natural component that is toxic to many other plants.
03
Never use sawdust from pressure-treated or other chemically-treated wood in your garden.
04
Sawdust sometimes attracts unwanted insects like ants and termites (depending on where you live). Be selective in where you use sawdust, especially for mulching and pathways.

Sourcing Sawdust

As you can see there are many uses for sawdust and it is an abundant renewable source... we have mountains of it! Azwood offer bulk deliveries of sawdust throughout the South Island. Please contact us directly if you would like to know more.

Enquire about sawdust

*Can order in quantities of 7m3 or more.