A photoprogramming controlled drip irrigation system and its effect on the yield of tomato crop grown on perlite substrate

Tomato plants were grown in a hydroponic system using plastic bags filled with perlite as growing media. Half of the plants were irrigated by a drip system controlled by a photoprograming timer. The other half of the plants were irrigated by a drip system controlled by a simple timer, adjusted by the grower each week. The former system gave a significant fruit production increase, while the latter system showed large variability in fruit production.