A guide to mulching

Garden Life
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Tips from Sarah the Gardener

If you look about in nature, you generally won’t find bare soil. It’s not a natural state in nature and so plants will always try and colonise it. In our gardens, we like to control what grows there and through the act of gardening, we can end up creating beds with bare soil surrounding our chosen plants. Any other plants that come along to take advantage of the situation are considered weeds.

However, the soil doesn’t react very well to being bare and in the hot summer months, it can even form a crust that will actually repel water. In this situation you can water as much as you like, but moisture won’t soak into the root zone where it is needed most – it will just roll away.

In order to protect our well-prepared garden soil from an invasion of opportunistic weeds, help it retain its moisture and avoid it becoming sun baked, mulch can be a great solution. But not all mulches are created equal and while some may do a great job in an ornamental garden, in the veggie patch it is a good idea to make an informed choice


Wood Chips

As the wood breaks down, large wood chips can actually draw the nutrients from the soil that your plants need to grow. Since this can be counter-productive, it is important not to incorporate the chips into the soil itself. Once you have added wood chips, it can also cause problems getting a fine tilth (soft fluffy soil with hardly any lumps) for sowing seeds directly into the garden in the following seasons as wood generally takes 3 – 5 years to break down. Once it has broken down it is a rich fertile mix, but until then – it is a lumpy, nutrient thief that is difficult to work around. If you decide to use wood chips then feed the soil regularly to replace what is stolen. Blood and bone is good for this. Having said that, there is nothing wrong with using wood chips around trees, shrubs and other ornamental plants as their demands for nutrients aren’t as great as that of hungry veggies and short lived annual flowers.

Sawdust

Sawdust can work well as it would be quicker to break down than bark chips. It can be a little acidic though and can still rob the soil of nutrients if incorporated into the soil. Considering this, feed well with blood and bone and maybe add regular doses of lime. Also make sure that it comes from untreated wood.

Pea Straw

A thick layer of this is a good choice. As it breaks down over the season, not only does it keep the moisture in and weeds down, but it also gives goodness back to the soil. You can buy it in bales or in a handy pelletised form. The downside is that the bales may have pea seeds in it that will germinate and grow. Although the roots will fix nitrogen and enrich the soil, they will pop up where you don’t want them and over the summer months they could attract mildew into the garden. It is best to just pull them out when they pop up. The problem with the pellets is the cost, by the time you have covered your whole garden at the recommended rate, then you will find you have spent quite a bit.

Compost

This is often recommended as a good mulch and yes, a good layer of compost will keep the moisture in, but it is also a rich, fertile growing medium – perfect for weeds to grown on top of so you will need to remain vigilant and weed often.

Weed Matting

While this may seem like a simple easy solution, it can actually damage the soil and make it ‘sour’ (a little too acidic). Natural elements, like rain, are unable to penetrate through the weed matting efficiently and the air flow is restricted. Also, the sun heats up the ground below it since most of the matting you will find is black and therefore it can do a bit of damage to your soil ecosystem. Slugs tend to like hiding in its folds and the most determined weeds find a way through but become stuck tightly making them really hard to remove. Weed matting is generally made from non-biodegradable plastic so aren’t all that environmentally-friendly. Some varieties are constructed in a woven fashion from thin strips that can easily unravel. These long strips can be a real long-term problem in and around the garden, especially if they get caught in the lawn mower! This is a mulch to avoid.

Lawn Clippings

These may seem like a good free idea, however there are a few drawbacks. Fresh grass clippings are full of nitrogen, and in most cases, you don’t want to encourage a fast green growth that is all lush but has no substance. You need a slow steady balanced growth. Also grass clippings have a tendency to go mushy, rot and stink, but also exclude the air from the soil, turning it sour and harming your plants. It can also introduce weed seeds that may start growing in your garden. However, if you mow often and therefore prevent weed seeds forming in your grass and you allow your grass clippings to dry out, you can apply them in gradually in light fluffy layers and should get away with it.

Hay

It may seem like a good cheap idea, but hay is FULL of weed and grass seeds so you might as well chuck lawn seeds over your garden and be done with it!

Straw

This is good to use, but not always all that easy to get hold of. If you can get your hands on some then go for it. Apply it in nice thick layers.

Newspaper

This is a great way to upcycle and help out your garden. Shredded is better than whole sheets, but it should be kept damp or it will blow away! Try not to use the shiny printed pages as the ink isn’t as friendly as the ink used in newspapers. If you are concerned about the ink, give your local newspaper office a call and ask. The downside here, apart from it wanting to blow away, is it looks a little ugly.

Leaves

Leaves that were collected last autumn and shredded are a perfect mulch. Leaves left whole can provide great places for slugs, snails and other critters to hid in. You can shred them by running over them with your lawn mower and collecting them in the catcher. Or you can create a lovely crumbly leaf mound to cover your soil, but setting aside your autumn leaves for about a year to break down. This mulch is the one the mimics nature the most and works well in the garden.

Whatever mulch you decided to use, take care not to mulch right up and around the base of plants as this can cause them to rot. Constant weeding and watering can easily turn the pleasure of gardening into a chore. By giving your garden the right protection, it can take a lot of the effort out of caring for your garden. It just makes sense to mulch.