Alternative materials to use for a growbox garden

I am planning to garden one acre of tomato and one acre of melons with grow boxes. i planned for 60' by 18" grow boxes. as in india, it is difficult to get sawdust to fill the grow boxes for two acres. we can easily get cocopeat (used in growbags for hydroponic cultivation) . can we use cocopeat and sand (sand from river used for construction. please give me in what ratio we can prepare the media for filling the grow boxes with cocopeat and sand. i planned to cover all the four sides of one acre plot with shade cloth (3 meter Height) to prevent wind damage.will it affect the pollination. thank you for extending your expertise in gardening with us.with best regards

Group:Cocopeat, also known as cuar (sp), or ground-up coconut husks, is excellent to use. It lasts a LONG time and has excellent water retention characteristics.Mix it 2/3rds cocopeat and 1/3rd sand, by volume.Pollination by air movement doesn't need much of it, so you should be alright. If you feel your tomatoes aren't pollinating well enough you might run your hand through the plant leaves occasionally. Usually, the activity of pruning and removing sucker stems is sufficient for pollination.Jim Kennard