You might think that if you’re considering putting any kind of mulch around your flower gardens or planting beds, you’d always be better of choosing natural, organic material as opposed to something man-made.
However, despite the popularity of wood mulch over the years, many gardeners have decided to turn their backs on wood in favor of using rubber mulch instead. Why is this? And which is better? Let’s take a look.
What is Mulch?
Before we get started, it might help to explain what mulch is – skip on to the next section if you’re an experienced gardener just looking for the comparison.
Mulch is material that is spread on top of soil, usually around bedding shrubs or trees. It’s placed there for several reasons, including:
- insulation, particularly at times when soil is vulnerable to cold snaps and frost
- preventing weed growth
- improving drainage
- improving the aesthetic of an area
You’ll often see mulching used as a landscaping option in areas where there would ideally be less need for dealing with weed growth, such as grass verges and garden beds owned by local government. Mulch makes the area look tidier, but also cuts back on gardening costs.
Additionally, many new buildings feature beds where exposed soil is covered with a 2-3 inch layer of mulch. This is to bring them up to code with the environmental protection agency and earn the status of ‘energy star certified home.’
Last but not least, mulch is used by many gardeners to improve the quality of their gardens.
Traditionally, wood chip mulch has predominantly been used, as it not only performs the necessary function but over time decays into the soil, and is therefore recycled before being replaced. In recent years, however, there has been a rise in the use of rubber mulch, for reasons we’ll now explore.
What is Wood Mulch?
Wood mulch consists of any kind of recycled wood matter, chopped up finely into wood chips and spread over an area. It is typically made from organic matter such as reconstituted wooden pallets, tree bark, leaves, and trimmed branches.
If you’re landscaping your gardens and need mulch, it is normally readily available at local timber yard or store, and is typically sold by the bag.
Pros of Wood Mulch
Wood mulch has several benefits:
- It biodegrades over time, adding nutrients as it is absorbed into the soil.
- Excellent weed suppression ability, great for low-maintenance landscaping.
- It can be tilled into the soil when weeding – instead of pulling up stubborn weeds by hand, you till the soil and mix them back in.
- Wood mulches give a more organic look to your garden
- Wood mulch is a natural by-product.
Cons of Wood Mulch
Using wood chips as mulch also has a few downsides:
- Wood mulch decays naturally over time, and will need to be replaced every two years or so, sometimes more often (if soil is nitrogen-rich it will break it down faster).
- Wood mulch requires nitrogen to decay, and so absorbs a lot of nitrogen from the soil. You may need to add extra nitrogen to compensate, which again could mean extra cost.
- Because it removes nitrogen, many gardeners advice against using wood mulch in vegetable gardens or some plant beds as plants need nitrogen for growth.
- Wood mulch is food for termites and other pests. Termites or carpenter ants can be highly destructive, especially if they move from mulch to a house or other property.
What is Rubber Mulch?
Rubber mulch is made from using old rubber tires. For many years, recycled tire rubber has been used to create a springy surface in children’s playgrounds but is now also being made into mulch products.
Mulching with rubber mulch has become more popular over the years because we now have better ways or recycling tires into rubber mulch. Rubber is a product that won’t decompose in landfills for at least 50 years, so finding another use for old rubber tires is important.
Let’s take a look at the pros and cons of rubber mulch material:
Pros of Rubber Mulch
There are many benefits to rubber mulch:
- Rubber mulch can last much longer in your garden bed when compared to wood mulch. This is because it is not absorbed into the soil and breaks down very slowly.
- Rubber mulch is heavier than wood mulch, so it is less likely to blow away or disintegrate in poor weather.
- It requires even less maintenance than wood mulch.
- Rubber mulch is has greater weed suppression capabilities. The shape and properties of rubber mulch mean that weed seeds don’t get the chance to settle and take hold. Weed growth is restricted because rubber is better at preventing weeds from taking over.
- Rubber landscaping mulch is a better insulator than wood chips and offers better water retention.
- It is not edible and does not attract termites or other pests.
- You can buy rubber mulch in a non-loose variety, either pre-rolled or in ring shapes to go around trees.
Cons of Rubber Mulch
Using rubber also has a few disadvantages:
- Rubber mulches are made from old recycled tires. These tires are made using a lot of chemicals that over time can leach into the soil. It may also retain trace metals which could seep into soil.
- The cost of rubber mulch is higher compared to wood mulch (see below), although this is offset by the fact that is can last much longer.
- Because rubber cannot be tilled into the soil, any upkeep has to be done by hand. To prevent stray weed seeds from taking hold, lay weed fabric over the soil first, before applying your rubber mulch ground cover.
- Rubber mulch is highly flammable. While both mulches can be set alight, rubber mulch burns faster and releases a toxic gas. In the same way that you should never burn old tires, you should be careful about heat near rubber mulch.
Is Rubber Mulch Cheaper than Wood Mulch?
To assess which is cheaper, we must look at both the initial and on going costs:
Purchased in bulk, you can get wood mulch for just a couple of dollars per cubic foot, while rubber mulch often costs upwards of $10 per cubic foot. However, wood mulch needs to be replaced every year or two, whereas rubber mulch will last much longer. Overall, rubber mulch is the cheaper option only if you want to keep the mulch in place for many years. Otherwise, wood mulch is cheaper.
Rubber mulch costs you significantly more in its initial outlay because it is not a natural byproduct and takes time and resources to produce from old tires. It’s also heavier, so you will need to pay more per meter squared of garden. Judging only on price, rubber mulch is often the worst option, however people choose it for its advantages – it suppresses weeds better, holds in moisture better, and requires very little maintenance.
The increasing use of rubber mulch on government parks and shrubbery tells you all you need to know about which one is more cost-effective in the long term.
Rubber Mulch vs Wood Mulch – Which is Best?
The best mulch material will depend on your needs. Both options are effective for mulching your garden, and both have real advantages and disadvantages.
If cost is your main deciding factor, wood is cheaper for short-term use and rubber is cheaper for long-term use because it is so long lasting.
If you are concerned about using a natural product, wood mulch is the best choice. Although rubber is also a natural product, the rubber used in mulch has come into contact with chemicals and metals and may bring other substances in to the soil. Overall, wood is better for the soil – although be wary of it leading to a lack of nitrogen.
Finally, there’s the look of the thing. Rubber looks less messy – it stays in place better (being heavier) and can even be bought in more solid chunks and rolls. However, the natural look of wood gets our vote. Which mulch option will you choose?