rhs compostMulch- a layer of natural material spread thickly over the soil cuts down the need for watering, reduces weeding and protects and improves the soil. Mulch matting is also available from most nurseries and garden centres and can be an effective way to conserve moisture and prevent weeds.

Six types of loose mulch

  1. Bark chippings- attractive, but expensive (unless you have a supply from your own felled timber or know a friendly tree surgeon who will give you a load for free). Large chunks will last a long time and don’t blow around, though deep wood chips won’t rot quickly. Use chippings that are at least a year old as the early rotting process will ‘rob’ the soil of nitrogen.

  2. Cocoa shells- pricey but has more nutrients than most mulches. They bond together when wet so they won’t blow away.

  3. Garden compost, manure and leaf mould- free, but soon rots away. Can spread weeds unless well broken down. Compost and well-rotted manure add goodness to the soil as well as improving and protecting it, leaf mould acts as a protective layer and improves soil texture, but is less nutritious.

  4. Grass clippings- free, but turns yellow and can introduce weeds. In wet weather, they can become slimy.

  5. Composted bark- attractive, but can blow around and may support wind-borne weed seeds. Does not last as long as chipped bark.

  6. Gravel- attractive, and long -lasting, but does not add organic matter to the soil. Various grades available.

Oh, and straw can also be used around vegetables and of course strawberries (to conserve moisture and protect ground laying fruit), and if you can get hold of it, shredded paper also works!

Shredded paper mulch around dahlias

Shredded paper mulch around dahlias

No-Dig gardening, Sheet Mulching and Hugelkultur

Sheet mulching, No-dig gardens and Hugelkultur have a fair bit in common; basically using organic matter in large quantities to provide a rich growing medium without the need for digging. It depends what school of gardening you’re from as to what your preference is, coupled with your conditions.

No dig gardens rely on adding copious layers of organic material over the soil without digging it, allowing the mulch to break down and form a rich top soil, into which vegetables and fruit can be directly planted. You need lots of organic material.

Sheet mulching

Sheet mulching

Sheet mulching (or ‘lasgane gardening’) has a similar premise to no-dig. Smother the undesirable plants, mulch heavily, make a ‘lasagne’ of carbon and compost, and plant lots. A good initial burst of energy brings minimal labour further down the line!

Hugelkultur

Hugelkultur

Hugelkultur (‘hill culture’) are no-dig raised beds with a difference. They hold moisture, build fertility, maximise surface volume and are great spaces for growing fruit, vegetables and herbs.

Effective mulching

Apply at the right time- mulches need to be in place by mid spring when the soil is at its wettest but is no longer cold. There is no point applying a mulch in dry summer conditions because it will stop moisture from getting to the plants and they will require even more watering than usual. Applying compost or well-rotted manure to fruit bushes and trees in the autumn and early spring will give them a boost, and applying leaf mould to bare soil in Autumn can be an effective protective layer to reduce the leaching away of nutrients in the soil during wet winters.

Apply the right thickness- to ensure effective weed control, apply a minimum thickness of loose organic material or gravel of 5cm (ideally 7cm) straight onto the soil surface.

Feed and water plants- add fertiliser before applying a mulch in spring time. Lay a seep hose under mulch matting so that you can supply water easily if needed.

Mulch in rows- when planting vegetables or bedding plants in rows, lays strips of mulch matting along the bed between the plants rather than planting them through the matting.

Problems with Mulches

  • Some mulches can be unsightly or troublesome when scattered by foraging birds

  • All mulches provide refuge for slugs and some types are a refuge for snails

  • If mulches are laid in direct contact with tree stems they can cause it to soften, making it vulnerable to disease

  • A build up of mulch can produce a hard layer, which is difficult for water to penetrate. Avoid this by only replacing mulch when it has rotted away or fork the remaining mulch into the soil

The outcome of piling mulch up around tree stems- 'volcanoes'

The outcome of piling mulch up around tree stems- ‘volcanoes’

Sources and further information:

‘Short Cuts to Great Gardens’- Reader’s Digest 1999

RHS- Mulches and mulching

RHS- Fruit Trees- feeding and mulching

Milkwood blog– S is for Sheet mulching

Permaculture – Hugelkultur

Proper mulching- no mulch volcanoes

Old School Gardener

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