Not all the experiments are done in the laboratory, many of them are done in the field. Depending on the size of the experimental set up or the equipment required, an experiment's location is decided. For example, titration of a solution can be done in a laboratory, but the transport of a tracer in a water stream can only be studied in the field setting. Similarly, agricultural scientists often use large tracts of land to actually grow crops and then study the effect of various parameters (say, season, rainfall, fertilizer and pesticide quantity, etc.) on the crops. In general, small-scale experiments are first conducted in laboratory and once parameters are fine-tuned (or selected), the relevant experiment can be moved to the field setting (if need be). An interesting field experiment I once heard about included installation of generators at the bottom of sea to generate electricity from wave motion.
Hope this helps.