Pot size matters: a meta-analysis of the effects of rooting volume on plant growth

Themajority of experiments in plant biology use plants grown in some kind of container or pot.We conducted a meta-analysis on 65 studies that analysed the effect of pot size on growth and underlying variables.On average, a doubling of the pot size increased biomass production by 43%. Further analysis of pot size effects on the underlying components of growth suggests that reduced growth in smaller pots is caused mainly by a reduction in photosynthesis per unit leaf area, rather than by changes in leafmorphology or biomass allocation. The appropriate pot sizewill logically depend on the size of theplants growing in them.Basedonvarious lines of evidencewe suggest that an appropriate pot size is one inwhich theplant biomass does not exceed 1 g L. In current research practice ~65% of the experiments exceed that threshold. We suggest that researchers need to carefully consider thepot size in their experiments, as small potsmaychange experimental results and defy the purpose of the experiment. Additional keywords: container volume, experimental setup, meta-analysis, pot size, plant growth, rooting volume. Received 16 February 2012, accepted 11 May 2012, published online 15 June 2012