Improving Soil with Natural Pumice

If you want your plants to grow optimally, with lush foliage and vibrant blossoms, then you have to focus on the quality of your soil. 

The root systems of all the plants need continuous oxygen supply. 

Moreover, the root zone must be able to remove the carbon dioxide produced by the roots.

natural pumice used to improve a succulent or cactus soil mix
Satakorn.s | DepositPhotos

This continual and smooth exchange of gases done through the soil and is crucial for plant growth. 

Therefore, soil amendments are necessary to improve nutrients and water retention. 

Adding pumice mulch to the growing media and garden soil may help in enhancing the quality of the soil.

Soilless media is made up of organic matter and a coarse mineral to enhance drainage. 

Create this by mixing pumice or perlite and peat moss, to maintain or restore the proper soil structure of your, ground covers, bonsai gardens, or as a top dressing or combined with the topsoil of your potting mixes.

What is Natural Pumice?

The pumice stone is a highly porous lava rock, which is formed during the eruptions of volcanos. 

It is commonly used as a lightweight concrete aggregate, as abrasive in numerous consumer and industrial products, as well as for horticulture and landscaping needs.

The pumice rock is also used as a decorative ground cover for planters and landscapes and as a soil conditioner for plantings for aeration and moisture regulation. 

Unlike other volcanic rocks utilized in the gardens, like vermiculite and perlite, this rock is directly used without the need for any industrial treatments.

What Benefits Does It Provide?

Pumice is highly porous, which is the main reason it is excellent for soil improvement. 

The numerous benefits of using natural pumice in any potting media include:

  • It helps in amending weak soil structures, like heavy clay soils, by creating friability and tilth, enabling the development of deep-rooted and vibrant plants.
  • It enhances soil absorption by reducing fertilization and water runoff in sandy soils.
  • Pumice is inorganic and doesn’t compact or decompose over time. 
  • It is reused and recycled continuously.
  • It is pH neutral.
  • It is an exceptional addition to composts, as it mitigates the volatilization in the composting and contributes in-soil.
  • It increases the drainage and aeration when growing succulents, cacti, or during the process of root cuttings.
  • It may be mixed with other organic matter to further enhance the potting soil.
  • It decreases shrink-swelling, flooding, cracking, and crusting.
  • Pumice soils don’t host or attract pests or diseases.
  • It strengthens plant roots.

How to Use Natural Pumice?

There are several ways to use pumice in landscaping and horticultural purposes.

  • For succulents, cacti, and other similar plants which don’t do well in wet soil, mix equal parts each of pumice, garden soil, sharp sand, and organic compost.
  • For cactus-like plants, which are vulnerable to rotting, combine half the amount of pumice with the soil mix to enhance the quality of the soil. 
  • If soil amendment is not an option, place pumice on the planting hole, so the roots surround the rock.
  • Use it as topdressing for rainwater absorption to prevent standing water around the plants.
  • For potted plants, pumice may be used as per the requirements of each plant. 
  • For succulents, mix the pumice soil with any bagged, inexpensive potting soil. 
  • For fine-leaved plants, combine one part of pumice with two parts of potting soil. 
  • For euphorbias and cacti, use two parts pumice and one part potting soil.
  • Numerous gardeners being offsets and rot-prone cuttings in pure pumice.

Some of the high-quality pumice products include Hess pumice, or you may also use horticultural pumice as needed. 

Use the pumice directly from the bag to the potting mix or saturate it with more beneficial microbes and nutrients. 

This process is known as supercharging or activating. 

To activate the pumice, soak it in a solution, like compost tea, for one day at least before adding it in the garden soil.

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