Greenhouses around the world are home to many different crops and varieties. Regardless of the type of cultivation, the common goal of commercial growers is to increase production. Production does vary strongly between different crops; ornamental crops are mostly sold by the piece, while in vegetable production, only the fruits are defined as produce. In both cases, production is a result of crop growth. This increase in size and weight of a plant, is what we define as crop growth.
On the short term, crop growth is dependent of complex chemical/biological reactions that occur in the growing areas in the plants. Just like a factory, all sorts of raw materials are combined and eventually turned into a product. In this case, the raw materials result into new plant-material. The sourcing of raw-materials occurs in different ways. The plant, for instance, is able to make sugar themselves through the process of photosynthesis. Other raw materials are taken in through the air (carbon dioxide) of from the growing medium (water and minerals).
Cell Division (mitosis)
All plants consist out of a considerable amount of cells. In the growing-points there are cells that divide themselves. In these split cells, all the parts of the cells are duplicated, which results into a new (cloned) cell. This process is called mitosis in biology. The two new cells together are of similar size as the original dividing cell. Just after the cell division, the plant hardly increases in weight. For the construction of the new cell-wall and the new cell organelles, sugars and a small quantity of minerals are needed.
After the cell division follows the cell expansion. The new cells are pumped up with water in order to regain the size of the original cell. With this process, the plant gains weight and size, and thus by definition, grows. For the cell expansion, mainly water is required, but also some sugars and minerals to form the expanding cell wall.
So, crop growth happens through the process of cell division and cell expansion. In order for these processes to occur, carbon dioxide, minerals and water are required. The plant is only able to use these raw materials under influence of light and in a crop-specific temperature-range.
Greenhouses and hydroponic cultivation allow us to facilitate this crop growth by ensuring that all required growth factors are in their place at the right time. By creating the right circumstances, the crops do what they want to do, grow.