CALCIUM, IRON, POTASSIUM, PHOSPHORUS, AND VITAMIN-C CONTENT OF ORGANIC AND HYDROPONIC TOMATOES

Two tomato (Lycopersicon esculentum Mill.) cultivars were grown in two organic and two inorganic media to evaluate the effects upon the leve ls of Ca, Fe, K,P, and vitamin C in the fruit. 'Platense' tomato was g rown in a glasshouse, on sand or peat-perlite (hydroponic substrates) irrigated with a complete solution of macro and microelements, or on 1 00% vermicompost or 50% vermicompost-50% soil (organic substrates) irr igated with water. Fruit were harvested at physiological maturity, and levels of P, K, Ca, Fe, and vitamin C were determined. Fruit grown on organic substrates contained significantly more Ca and vitamin C and less Fe than did fruit grown on hydroponic media. Phosphorus and K con tent did not differ between fruit from organic and hydroponic substrat es.