Pookalam' consists of two words, 'poov' meaning flower and 'kalam' means colour sketches on the ground.

The floral carpet, known as ‘Onapookalam’ is made out of the gathered blossoms with several varieties of flowers of differing tints pinched up into little pieces to serve the decorator's purpose. It is considered a work of art accomplished with a delicate touch and a highly artistic sense of tone and blending. Traditionally, Atthapookalams (pookalam made on the Atham day) included flowers endemic to Kerala and the Dashapuspam (10-flowers), but nowadays all varieties of flowers are used. Commonly used flowers include Thumba (Lucas Aspera), Kakka Poovu, Thechipoovu, Mukkutti (little tree plant), Chemparathy (shoe flower), Aripoo or Konginipoo (Lantana), Hanuman Kireedom (Red pagoda plant) and Chethi (Ixora). Of all these flowers, Thumba flowers are given more importance in Pookalam as they are small in size and glitter in the the soft rays of the sun. 

Earthen mounds, which look somewhat like square pyramids, representing Mahabali and Vamana  are placed in the dung-plastered courtyards in front of the house along with the Pookalam.

Earlier, people used to make efforts to collect flowers for designing a Pookalam. Children used to get up early in the morning and gather flowers in their small 'Pookuda' (basket) from the village gardens. These days, the trend has changed and people have the option of buying flowers from the market in the shape and colour of their choice. 

In the recent years, the floral designs have evolved from the traditional circular shape to unique designs depicting different cultural and social aspects of Kerala life. All over Kerala, Pookalam competitions are a common sight on Onam day.