Re: Do plants grow better in soil or sand? Why?

The answer can be yes or no depending on the situation. Actually, sand is a 
type of soil. Soils are composed of three particle sizes: sand (0.05 to 2.0 mm 
diameter), silt (0.002 to 0.05 mm) and clay (less than 0.002 mm). Soils are 
named based on the percent by weight of sand, silt and clay they contain using 
a soil textural triangle.

Sandy soils generally have low fertility, low water holding capacity but high 
aeration. Aeration is important because plant roots require oxygen. High 
aeration also means water will drain quickly from the soil during heavy rain. 
Fertility is a measure of how well the soil can supply the plant with essential 
mineral nutrients such as nitrogen, phosphorus and potassium. Clay soils 
usually have high water holding capacity and high fertility but low aeration. 
The best soils for plants are usually a mixture of sand, silt, and clay, termed 
loams. They have good levels of fertility, water holding capacity and aeration.

Sandy soils can grow excellent plants if adequate water and fertilizer are 
supplied. If watering is infrequent and adequate fertilizer is not applied, 
then plants in a loam may grow much better than those in sand. Plant 
researchers used to grow plants in pure sand for mineral nutrition experiments. 
Grass growing in pure sand is popular for golf putting greens and football 
fields in pro and college stadiums because sand does not compact like loams, 
drains well even during heavy rain, and doesn't muddy uniforms.

Reference


Soil Textural Triangle