Coarse Sand is Horticultural Gold.

Coarse sand is one of the most useful materials I know of for plant propagation & growing media; these days it is one of the hardest to obtain for horticultural enthusiasts:-

 So, what is it?

This sand (pictured above) is typical of what I'm after. In terms of size the grains range from roughly 2 to 5mm diameter, with the majority falling toward smaller particles.

The illustrated material has been mined from a natural source, river sediment, so in this instance contains some fine sand & silt, along with a fair bit of small pebble. It consists mostly of quartz, silicon dioxide, with a few impurities adding colour to the rock. Suitable sands may be pure white, especially if created by crushing quartz; yellow or greyish colours are also common, depending on the chemical make-up of the parent rock. The most important component is a high quartz content.

Propagating sand, horticultural sand, sharp sand, quartz sand & coarse sand are all interchangeable terms that describe the subject material. When I was a kid this would also be described as aquarium gravel, back in the days before under-gravel filters.

Compare the above photo with the widely-available river sand pictured below:-

 

 

Note the small particle size compared to the coarse sand. When added to potting mix fine sand tends to fill in air pockets that contribute to drainage, increasing water retention and decreasing aeration of the root zone. Water is held on the surface of each sand grain; with so many particles this makes a fair contribution to water-holding capacity. There is also the compaction factor, with sand-rich mixes quickly becoming brick-like in consistency. Once dry, sandy mixes are hard to rehydrate; water often wets the top of the mix then runs down between root ball & pot, with little infiltration where it's needed. This hydrophobic property is common with sandy soils & requires application of a wetting agent to restore adequate soil moisture for plant growth.

Succulent mix is pictured below:-
 

'

This was made up with:

 

                       *60 litres of Martins Garden Mix



*15 litres of coarse river sand

*10 litres of p500 grade perlite

*3 litres of pelletised chicken manure

*1 handful of garden lime

*1 handful of blood & bone

*1double handful of crushed basalt (blue metal dust)

 

The above potting mix can also be used for cacti, but I usually add extra coarse sand &/or perlite to increase drainage based on feel & appearance, just like an experienced cook. My cactus mix is also a bonsai mix due to its' rapid drainage.

 

A general carnivorous plant mix suitable for Sarracenia & Drosera is pictured below:-

 

 

This is made up of:-

*2 parts premium grade spaghnum peat moss

*1 part p500 perlite

*1 part coarse sand

 

The coarse sand must be well washed with all dirt & silt removed as these contain nutrients; carnivores generally grow in poor soils & will not perform if the medium is rich.

 

I have used a similar mix to the one above to strike Camellia cuttings, adding extra perlite.

 

Coarse sand is great for striking many plants on its' own, including orchid canes & bulbs, Cordylines, cane Begonias,

Pelargoniums, shrub cuttings in general & in particular any plant with succulent properties:- 

 

 

The picture above shows Pedilanthus cuttings planted last spring , emptied out of a community pot ready for potting up into single pots.

Here washed coarse sand has been used as a sterile top dressing for a native violet cultivar to help arrest rotting during our humid summer:- 

 

Many of the smaller native violet cultivars come from cooler less-humid climates & are prone to die back during hot sticky weather; a topping of coarse sand reduces soil splash and resultant leaf-spotting. Note the original plant in the pots' centre, now dead, & the healthy new growth remaining.

 

I find this technique is useful with Kangaroo Paw.

 

UPDATE

 

Seedlings For Sale at The Niche.

 

Vegetable & flower seedlings will be in stock during September till mid-October, possibly longer if in demand.

Herbs available, most commonly-used varieties.

AT BARGAIN PRICES!!!!!!!!!!!

Herbs:-  $3.50 or 3 for $10

Punnets:-  $3.75

Single pots (tomatoes, capsicum etc.):-  $3.50 

 

Locally grown outdoors.