What type of irrigation system floods water across the greenhouse workbench?

The ebb and flood system is specifically designed to manage water by flooding a growing area with nutrient solution and then allowing it to drain back, making it an efficient method for irrigating plants in a greenhouse setting. This method involves raising the water level to cover the workbench and then allowing it to recede, which promotes nutrient uptake and aeration of the roots.

In contrast, a drip irrigation system delivers water directly to the plant roots through a network of tubes and emitters, focusing on targeted irrigation rather than flooding. A sprinkler system disperses water in droplets through overhead sprinklers, simulating rainfall, and is typically used for broader coverage rather than targeting a specific area like a workbench. Soaker hoses provide a slow release of water along their length, soaking the soil but not flooding or inundating the entire workspace effectively.

Thus, the ebb and flood system is distinguished for its unique ability to completely flood a greenhouse workbench area, making it the correct answer.