Mulch Fiction
I think it’s widely accepted that mulching is good. It suppresses weeds, protects the soil from our baking sun, helps retain moisture and, if it’s an organic mulch, slowly breaks down over time and improves your soil.
What’s more hotly debated, or at least the subject of some very strong opinions, is what kind of mulch you should use. I’ve heard people wax lyrical about xxx being the only mulch they will use.
Wanna know what I use? All of them. All mulches have their place and are good for different things.
Last weekends efforts!
Last weekend I got over a cubic metre of cypress wood chip and re-did my rose bed, and the more ornamental gardens either side of my deck. Cypress timber is naturally resistant to termites (helpful with a wooden house!), but any coarse wood chip will have the same effect. Nice big chunky pieces take a long time to break down, fostering some amazing fungi and mycorrhizae in the meantime - and isn’t biological life in soil the aim of the game? Wood chip is perfect for paths and garden beds with trees and shrubs. If you want to add a few annuals for colour, simply push the bark aside, plant your plant and push it back!
Some pretty cool mycelia (fancy word for a mass of threadlike fungi roots) in a damp, undisturbed patch of wood chip.
For vegetable beds and garden beds with fast growing crops, like cut flowers, lighter straw type mulches are best - sugarcane, Lucerne, pea straw. They can usually be found in a coarse hale-bay style, or chopped more finely. It doesn’t really matter which one - the fine stuff breaks down quicker, but can get compacted more easily and stop water penetrating, whereas I find the long stringy bits of the coarser types can swamp small seedlings. Either way, if they get dug into your soil while you’re ferreting around, they’ll break down quickly and you won’t be left with chunks that impede the growth of your seedlings.
Chopped sugarcane mulch in my veggie patch
One of the reasons a lot of people don’t like woody mulches is ‘nitrogen drawdown’. Basically, mulch materials are made of carbon, and as microorganisms start to break them down, they need nutrients from the soil - the main one being nitrogen. Nitrogen is the also the main nutrient you plants need, so it’s not great that it’s getting ‘used up’ when you put mulch down! The larger your mulch pieces, the more nitrogen is required, ergo some people refuse to use the chunkier bark mixes. BUT, the nitrogen is released back in the soil as the carbon is broken down and the organisms die off (such is the cycle of life!). If you use woody bark mulches on bigger shrubs, their roots penetrate deeply and they ride the wave of what’s available. Even straw mulch in a veggie patch requires nitrogen to break down - the cycle’s just quicker. And you should also be adding compost and manure every time you mulch, which helps level it all out, meaning your leafy greens always have a steady supply.
One more point - different types of mulch foster different microbiological activity. So if you change up the type you use, you’ll encourage a wider variety of soil life.
I also like the mulch blends, they’re a little bit chunky and a little bit fine… and fallen leaves and twigs blend in better!
If you’re interested in how I start my garden beds from scratch, check out my how-to guide here, otherwise, now is the perfect time to get out there and put some mulch down before the heat of summer hits. Happy mulching!