Chippings & Mulch

Using the chippings

Once a stump has been ground out and is a pile of wood chips, the chips can be used as mulch or compost. The decomposition of chippings in garden soil causes microbes to absorb nitrogen and upset the ph balance, so below you'll find notes on preparing the chippings to be useful in the garden.

Flower Beds

If the stump was very small (less than 8-12 inches across), in a flower bed you can disperse the chippings widely in the surrounding soil and flower bed. A periodic ph check will show if you need to add nitrogen to reduce acidity.

If the stump was larger and you intend to replant, all chippings should be removed and the hole needs to be filled with fresh topsoil: fresh chippings used as mulch around annuals and perennials will probably kill them.

Out of the way spots

The pile of chippings and churned earth can be left over the hole - nature will level the pile.

Lawns

If you wish to grass the area where the stump was, all the chippings must be removed and fresh topsoil imported. If you don’t, seed will not flourish and turf will perish.

Using the chippings

Chippings can be used immediately to cover paths or play areas; chippings decompose slowly and soften the surface. If you have more than you can use you may be able to help a neighbour. You can also use them as mulch around mature trees and shrubs.

Wood chips from different trees have different levels of acidity; ash, beech and oak chippings can usually be used immediately around established subjects, and wood chips from conifers may be used to mulch a Leylandii hedge.

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To be on the safe side, chippings can be composted and the compost can be used to benefit trees and shrubs in the garden.

Composting chippings

The process of composting is chemically complex. Small quantities of chippings can be added, a layer at a time, to a compost heap, particularly if it is mainly grass clippings; the wood chip will add fibrous material. The time taken to turn fresh chippings into compost varies according to the mix:

Three Years: Chippings on their own will compost.

One year: Mix in an equal volume of grass clippings or 5lbs of urea per cubic yard, and leave to decompose. Either additive will provide the necessary nitrogen to compost the mixture.

Three months: As for one year but turn the pile over every week for one month, and every two weeks thereafter, and keep adding sufficient water to keep the pile moist.

Mulching

Composted chippings can be used as mulch, which is great for growing gardens. The best use of wood chip mulch is around trees and shrubs. In the border, properly applied, composted wood chip mulch will suppress weeds, enhance plant growth, conserve soil moisture and insulate soil from temperature fluctuations.

The mulch should be laid no more than 4 inches deep and tamped down. If you are mulching trees or shrubs, the mulch should extend beyond the canopy, and be 6 inches away from the trunk.

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If you are making a new planting in a lawn, remove the turf to a diameter of 3 feet greater than the planting hole and apply the mulch as above. If the tree to be mulched is established in a lawn, do not remove the turf before mulching, as this may cause surface root damage.

Re-growth and Stones

The grinding process will prevent re-growth of almost all trees. However willow, poplar and some varieties of flowering cherry for example have a habit of regenerating, sometimes up to 5 years later. - you may have heard of the willow walking stick stuck in the ground in autumn, which sprouted roots by spring! Glyphogan is a recommended herbicide in such cases.

The grinding process may have propelled some stones and stone chips onto the lawn: before mowing, take care that all stones have been removed; they can blunt the mower and, if thrown up during mowing, can be dangerous to people, pets and glass.