Srimad Bhagavatam Canto 02, Chapter 06, Text 24

SB 2.6.24

tesu yajñasya pasavah
savanaspatayah kusah
idam ca deva-yajanam
kalas coru-gunanvitah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
For performing sacrificial ceremonies, one requires sacrificial ingredients, such as flowers, leaves and straw, along with the sacrificial altar and a suitable time [spring].
Srimad Bhagavatam Canto 02, Chapter 06, Text 23
Srimad Bhagavatam Canto 02, Chapter 06, Text 25