Sustainability is becoming more and more important in the competitive battle between the greenhouse-grown fruiting vegetables produced in Spain and the Netherlands. A monitoring system has been developed. Sustainability is a broad concept regarding primary producers and other links in the chain. However, the greatest impact on the environment comes from the primary production. The first phase of the research is aimed at energy use and crop protection at the production level. Primary knowledge and experience of real experts of suppliers of horticultural inputs is used as a source of facts and developments. Physical production is lower in Spain and greenhouses are usually unheated. Primary fuel consumption per kg of tomatoes, sweet peppers and cucumbers is estimated to be 13, 14-17 and 9 times greater respectively in the Netherlands. Due to the lower prices in spring no widespread heating of greenhouses is expected in Spain in the near future. Innovation is therefore a slow process in Spanish greenhouse horticulture. It is estimated that 19, 16 and 24 times more active ingredients are applied per kg of tomatoes, sweet peppers and cucumbers respectively in Almeria than in the Netherlands. Biological disease control is common in the Netherlands and in Spain on less than 5% of the acreage. Biological disease control is used on 60% of acreage of sweet peppers in Murcia. This is related to the start of cultivation in winter and the low risk of virus infection by insects during that period. Heating is used on about 20% at the acreage of this crop and is beneficial for the reduction of the use of fungicides. This combination makes the picture of sweet peppers in Murcia more rosy.