Gardening: What is the best mulch for gardens?

Spring is a great time to apply mulch to the surface of the soil, particularly after weeds have been removed, as it will help suppress further germination as well as conserving moisture and generally looking good, giving the surface of the soil a refresh.

Depending on what mulch is used, it can act as a nutrient boost to the soil and plants as well.

What is the best mulch to use in the garden? This depends on what you are mulching, and what the aim is.

Here are a few of the most commonly used, and what they contribute to soil and plant health.

Straw applied to the surface of the soil has a lot of benefits, particularly if the straw is partially broken down already.

It can help to open up the soil structurally, retain moisture, and will suppress weeds.

Straw breaks down quickly and is carbon-rich so the application of a source of nitrogen before applying a straw mulch is a good idea.

A scattering of chicken manure pellets or FYM will ensure plants get the nutrients they need.

Cardboard is a great mulch for weed control, while recycling a household waste material.

It is best used in conjunction with another mulch like seaweed or garden compost on the surface to keep it in place.

It is a great one for creating new beds in grass areas as it eliminates light and kills the grass.

Slugs do like to shelter beneath the damp, dark cover, so be aware to this when planting out young transplants.

Wool is a great mulch in the vegetable garden, and one that the slugs do not like.

It retains moisture and suppresses weeds, keeps the soil cool in the summer and warm in the winter, eventually melting in the soil.

A great use for this by-product of farming that is no longer in as much demand for clothing production.

Grass clippings from cutting the lawn make a great mulch in the vegetable garden, the key is to ensure you just use a thin layer of no thicker than 10cm so that it dries out quickly while still suppressing weeds. Too thick, and it will become shelter for slugs, and become slimy and smelly.

Farmyard manure (FYM) is high in nitrogen with animal wastes contributing to this, and most commonly obtained directly from a farmer. It will generally be animal waste mixed with their bedding which can vary from straw, wood shavings and bark.

Well-rotted manure is the best, as fresh manure may burn the roots of plants as the chemicals are not broken down enough.

When plenty of worms are in evidence, this is a good indicator that it is ready for application to the soil.

Generally, it would need 12 months to rot down well.

Mushroom compost is the growing medium used for growing mushrooms commercially and is made up of a combination of wheat straw, hay, horse and chicken manure, corn cobs and brewers grain. It has a pH of about 7 and this needs to be considered before using it to feed established shrubs.

It is a great soil conditioner, improving soil structure and texture and providing a nutrient boost for plants also.

Only really useful if there is a commercial mushroom grower near you!

Composted bark mulch is great to apply to the surface of the soil to suppress weeds and conserve moisture. There is not much in the way of nutritional value added to the soil, but it will eventually rot down into the soil and help improve the structure and organic matter content.

The dark colour of the well-rotted bark mulch provides a pleasing appearance in garden beds and borders.

Fresh bark mulch is best used on pathways as it will rob the surface of the soil of nitrogen as it breaks down, and plants also need nitrogen to fuel growth, so this will not be ideal around vegetables or annuals and perennials that will be obtaining nutrients from the upper parts of the soil.

Mulching mature trees and shrubs with fresh bark will not be a problem as they will have their roots established further down in the soil.

Garden compost is a great soil conditioner, helping to improve the structure, texture, and water retention capacity, and providing nutrients for plants also.

A mixture of brown and green materials should be left to rot for 12 months and produce a beautiful crumbly textured medium that can be applied to the surface of the soil.

Leaf mould is one of the best for improving soil structure, adding organic matter and improving water retention. It is not very high in nutrients and for this reason is often sieved and used for seed sowing as it has a lovely airy texture, ideal for new roots to establish in.

Applied to the surface of the soil in spring, it looks great with its dark and crumbly texture and brings great benefits to the soil.

Gravel and shale are inorganic mulches and can be applied to the surface of the soil after weeding to suppress weeds. Be aware that they will heat up during the summer and raise soil temperatures which may not suit all plants.

Fresh seaweed is an excellent soil conditioner and nutrient source for plants, providing valuable trace elements like iron, magnesium, boron and zinc.

Most practical for collection if you live near the coast, it retains moisture and suppresses weeds.

Chicken manure pellets are basically chicken manure which has been processed into a dried form, and while perhaps it is a stretch to consider them as a mulch, they are more a scattering to the surface.

These are a great non-bulky organic source of nutrients, they do little for the structure or water holding capacity of the soil, but they do provide a nutrient boost for established plants.

Just some of the mulching options to consider this springtime.

Happy Spring Gardening!