Effect of Biochar on Yield of Lettuce and Basil in Containers

Biochar (BC), the byproduct of fast pyrolysis of pine wood, was investigated as potting substrate on greenhouse-grown lettuce (Lactuca sativa ‘Black-seeded Simpson’) and basil (Ocimum basilicum) in containers.  Biochar was mixed with pine bark (PB) or a commercial substrate (SB) at 0, 20%, 40%, 60%, 80%, or 100% (vol.) ratio. For lettuce, in BC/PB mixes, none of the growth index (GI) of plants grown in mixes with BC was lower than that of plants in 100% PB, and plants grown in mixes with up to 60% BC had higher fresh weight than 100% PB. In BC/SB mixes, GI of lettuce grown in mixes with BC was similar to that of plants in 100% SB, and plants grown in mixes with BC had higher fresh weight than 100% SB. For basil, in BC/PB mixes, fresh and dry weight of plants grown in mixes with BC was similar or higher than that of plants in 100% PB. In BC/SB mixes, fresh and dry weight of basil grown in mixes with BC was similar or higher than that of plants in 100% SB.