Everything you need to know about mulching

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Mulching Strawberries

This is a fundamental technique for the well being of your vegetable garden, and allows you to recreate the conditions of growth for vegetables as found in nature.

More concretely, mulching in your garden involves covering the soil at the foot of your plants with hay comprising various materials of natural origin, organic and mineral.

You can apply this technique anywhere in the garden, buy must respect certain rules and choose the hay that is suitable to your plants to make this effective.

Mulching Strawberries
Mulch around strawberry plants

The benefits of mulching for your garden

When undertaken properly, mulching will offer a series of advantages which will improve development of your plants and facilitate management of your vegetable garden.

  • Less watering : Bare soil facilitates evaporation of water and transpiration of plants. Natural mulching allows these phenomena to be limited and acts as a sponge for better absorption of water during rainy periods. It also has a thick covering role which keeps the land fresh and avoids it from drying out in summer.
  • Avoids the slaking phenomenon :Clay and limestone soils tend to become compact and form a crust on the surface after rain. Mulching your soil with vegetable produce, for instance, avoids this.
  • Less weeding : Protecting your soil from light with mulching allows you to avoid proliferation of “weeds”. 
  • A more fertile soil : At the time of decomposition, your mulching will transform into humus and enrich your soil with essential nutrients for the growth of vegetables.
  • Less muddy crops : our climbers (strawberries, cucumbers, melons) will not be in direct contact with the soil, but with the mulching. 
  • Favours life for your soil : Mulching offers a protective layer reducing temperature discrepancies and humidity. It favours the development of microbes at the surface which allows for release of nutrients necessary for development of vegetables (mineralisation).
  • Reduces the risk of illness : The physical screen of mulching allows you to diminish the spread of illnesses during periods of rain when hitting the soil. This is notably the case of mildew spores which are projected onto leaves and twigs close to the soil.

How to choose your mulching ?

There are two different categories of mulching, mineral and organic. They include several different varieties and you should find that which is best suited to your soil or the type of plant you want to grow.

Mineral mulching

It is not biodegradable and its use is recommended for plants which are used to warm and dry climates.
We can distinguish between several varieties of mineral ulching such as crushed tiles, gravel, or flat stones. The most widely used remains pozzolan: this is a volcanic rock rich in silucon of which the alveoli structure constitutes solid thermic insulation.

Mineral mulching

Organic mulching

Beyond its function of protecting the soil, this type of mulching has fertilising properties when it breaks down and transforms into humus. It can be divided into two categories in line with its speed of decomposition.

Long life mulching > 4 years 

These should be used as sustainable cultures which require little renewal such as trees, bushes and living plants. You should exclude them if you are looking for mulching for a vegetable garden.

  • Wood chippings : These offer long term protection and you should provide fertiliser rich in nitrogen before spreading.
  • Pine cones : These are recommended for acidic plants.
  • Sizes of shrubs and pre-composted crushed bushes : If you have a crusher, transform your waste into mulching. However, make sure that you get rid of any conifer clippings so as to avoid adding acid to your soil.
Organic mulching

Mulching with an average lifespan < 4 years

These may be used for all types of vegetables and for short-cycle crops. 

  • Grass cuttings : You can recycle your grass cuttings by turnip these into mulching. But consider limiting its thickness to several centimeters to avoid rotting.
  • Not mature composts : To solely be used for already developed plants. Avoid contact with twigs and trunks so as not to lead to burns.
  • Linen and hemp mulching : This mulching, which has an excellent thermic insulating power, is very good for mulching for vegetables gardens and living plants. Moreover, the almost neutral pH, or marginally acidic nature, makes this ideal for rose gardens.
  • Dead leaves : Their excellent C/N ratio allows you to naturally compost at the foot of plants.
  • Buckwheat shells : Multi-purpose mulching which has a solid opacifying potential and repels slugs ad snails. It also allows you to limit reduction of othiorynques by its physical barrier.
  • Vegetable original mulching fibres : This may be used to create mulching for living plants or a hedge. It allows water and oxygen through, but not light. This particularity allows it to be used on soil already invaded by “weeds” and to transform these into humus after several months.
  • Cereal mulching : This is “traditional” mulching. However, it is difficult to find this which does not come from Organic Agriculture today. Moreover, the mulching tends to fly away and can also bring in other plant seeds which you do not wish to see in your garden (weeds).

Here are some examples of the lifetime of organic mulching :

  • Two to three years > linen  mulching, sunflower seeds, buckwheat shells  and hemp mulching.
  • Around one year > depending on their size: hay, leaves
  • Several weeks > Grass cuttings

How can you guarantee the success of your mulching ?

Now that you know the type of mulching adapted to your plants and the desired term of protection, you will finally be able to mulch your soil. Here are some tips which will help you to know when and how to mulch :

  • Do not mulch when it is windy.
  • Do not mulch on frozen soil, it will delay the reheating.
  • Mulch on a weed-free soil, unless you are using vegetable origin fibre mulching.
  • Abundantly water your soil before and after mulching.
  • Respect a minimum thickness of 5 to 10 cm. Aside foe buckwheat shells and hemp which have solid coverage power.
  • Separate your mulching into two or three passages before reaching the desired thickness so as to avoid smothering your young plants and vegetables.
  • Respect the gaps between your living plant areas so as they cover  your mulching one or two years after planting.
  • Add 2 to 3cm of mulching each year to offset the losses when you use an organic mulching with a short lifetime.
  • If you want to incorporate your mulching onto soil, do so in the Autumn

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