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 levels of Ca, Fe, K, P, and vitamin C in the fruit. 'Platense' tomato was grown in a glasshouse, on sand or peat-perlite (hydroponic substrates) irrigated with a complete solution of macro and microelements, or on 100% vermicompost or 50% vermicompost-50% soil (organic substrates) irrigated 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 content did not differ between fruit from organic and hydroponic substrates.