One type of potential seaweed that is quite abundant is Turbinaria ornata, nevertheless, it has not been widely developed through cultivation in Indonesia. Turbinaria ornata has a very important role in the industrial world as an alginate raw material. This study aimed to determine the application of the off-bottom method cultivation through spacing in supporting the growth (absolute weight growth and relative growth) of seaweed T. ornata. The construction of seaweed T.ornata cultivation is a rectangle measuring 25m x 10m, made of polyethylene ropes fixed with concrete anchors. In the cultivation construction, there are five stretch ropes. Each stretch rope is installed at a distance of 25cm. Placement of seaweed T.ornata cultivation containers, using the off-bottom method, was carried out at a water depth of 1 meter. The data analyzed are absolute weight growth data and relative growth rate. The results showed that plant spacing had a significantly different effect on the growth of absolute weight and relative growth of seaweed Turbinaria ornata. A spacing of 35cm gave the best results for absolute weight growth and relative growth of seaweed Turbinaria ornata.