All the qualities of carrot root except -carotene were significantly influenced by the particle sizes of perlite, the concentration of nutrient solution and/or their interaction (Table 4). Plants grown in perlite smaller than 1.2mm produced roots with higher soluble solids, ascorbic acid and lycopene content whereas those qualities were found to be decreased with the increase of particle size. -Carotene in roots was not different in particle sizes greater than 1.2mm but it was decreased in the smallest perlite particles (0.6mm). In 2.5 and 5.0mm perlite -carotene content was higher at higher concentrations (100–300%) but lycopene was found higher at 50 or 100% concentration. Lycopene content in root were higher in roots grown with lower concentrations (25 and 50%) of nutrient solution and it was decreased with the increase
of concentrations. These results indicated that quality roots were produced by the carrot plants grown in smaller perlite particles than those grown in larger particles.