Effects of maintained substrate water contents from transplant to early stage of potted Impatiens©
In the first few weeks of bedding plant production, growers rarely irrigate so as to bring the substrate up to container capacity (the point at which the substrate can hold no more water against gravity). Research has been carried out to determine effects of substrate water content on bedding plant growth. Van Iersel et al. determined effects of substrate water content on petunia (Petunia ×hybrida) (2010). The substrate was maintained at or above substrate volumetric water contents (VWC; cm3 water cm-3 substrate) of 5, 10, 15, 20, 25, 30, 35, and 40%. Shoot dry weight increased quadratically with VWC. There was a little increase in shoot dry weight between 25 and 40% VWC. All plants were well-watered uniformly for the first 9 days after being transplanted into the containers, and it took 9 days after irrigation treatment initiation for the substrate to reach the 5% VWC target. The substrate water content maintained during the first 9 days is not reported. Furthermore, substrate water content at container capacity was not reported. Therefore, it is not known how 40% VWC (the wettest treatment) compares to container capacity in the substrate and container used in the study.
Bowden, A.T., Newby, A.F., Fain, G.B. and Wells, D.E. (2016). Effects of maintained substrate water contents from transplant to early stage of potted Impatiens©. Acta Hortic. 1140, 431-436