Growing strawberries under covers in substrates allows to eliminate the application of soil decontamination, which is costly and harmful for the environment. At the same time it guarantees obtaining a higher and better quality yield, as compared to the traditional ground cultivations. In the years 2005–2006 studies were conducted, aiming at determining the effect of three kinds of substratum (peat, peat mixed with composted pine bark in the proportion of 1:1, peat mixed with composted pine sawdust in the proportion of 1:1) and differentiated nitrogen dose (140 or 210 mg N·dm^-3) upon yielding, chemical composition of leaves and fruit of strawberry (Fragaria × ananasa Duch.) of 'Honeoye' cultivar, grown in an unheated foil tunnel. The total and marketable yield quantity of strawberry fruit grown in peat and in peat with pine bark did not differ significantly. Lower total (407,1 g·plant^-1) and marketable fruit yield (264,6 g·plant^-1) was reported when plants were grown in peat mixed with sawdust. Plants grown in peat mixed with sawdust gave fruit with significantly lower unit weight compared to plants growing in the remaining substrates. The studies did not demonstrate a significant effect of differentiated nitrogen fertilization upon strawberry yielding. In the leaves of plants fertilized with nitrogen dose of 200 mg N·dm^-3 significantly more nitrogen was found, as well as less calcium, compared to plants fertilized with a smaller dose of this component. In the fruits of strawberry fertilized with a larger nitrogen dose, significantly more nitrates (V), total nitrogen and potassium were reported and less dry matter, extract and calcium compared to fruit collected from plants fertilized with nitrogen dose of 140 mg N·dm^-3.

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