Effect of companion plants on tomato greenhouse production

•Integration of companion crops in tomato greenhouse production was assessed.•White mustard and marigold as companion crops showed suppressive effect on nematodes.•White mustard decreased tomato yield and fruit weight, while marigold did not.•New data were obtained about the influence of companion crops on tomato fruit quality.•Tomato production has the lowest energy intensity in the marigold treatment.

The objective of this study was to assess the effect of companion plants as marigold (Tagetes patula L.), basil (Ocimum basilicum L.), lettuce (Lactuca sativa L.) and white mustard (Sinapis alba L.) on (i) greenhouse tomato yield and fruit quality; (ii) root-knot nematodes infestation and (iii) energy effectiveness of tomato production. The experiment was carried out during three consecutive years (2011–2013) in an unheated greenhouse. White mustard caused significant decrease in early and total yield of tomatoes as well as decreased the average fruit weight. Marigold, basil and lettuce did not decrease significantly the tomato productivity. Chemical parameters of tomato fruit quality, including antioxidants content, measured twice in a harvest period, were positively affected by the intercrop systems in most cases. Although all tested companion plants suppressed to some extent the development of Meloidogyne spp., the white mustard and marigold were the most promising ones having effectiveness of 53.45% and 46.38% against the root-knot nematode invasion. The control treatment had the highest energy intensity (1.43 MJ kg−1), mostly due to the costs for manual weed control. The manual operations for weed control in intercropping systems decreased three times. The lowest energy intensity (1.03 MJ kg−1) was established for marigold as companion plant of tomato. Based on the obtained results white mustard and marigold could be considered as most promising companion crops in greenhouse tomato production.