Date of Award

12-2015

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Plant, Soil, and Environmental Sciences

Advisor

Marianne Sarrantonio

Second Committee Member

Mark Hutton

Third Committee Member

Mark Hutchinson

Abstract

Greenhouse production has increased significantly in recent years in the United States. Potting media used in these greenhouses typically includes peat moss as a primary ingredient. Peat moss is harvested from sensitive bog ecosystems, which form very slowly. Finding an alternative for peat moss in container media could help slow the rate of peat harvest from these ecosystems. Compost has been studied as a possible partial replacement for peat moss in growing media. This study evaluated how the amount of food residual compost used in container media affects tomato (Solanum lycopersicum) growth and yield in container media. Seedling and flowering plant stages were evaluated in 2014 and 2015. Seedling treatments had 0% and 25% compost (100% and 75% peat moss, respectively). Seedlings were then transplanted into media containing peat, perlite and 0, 15, 30 and 45% compost to evaluate any effects to flowering tomato plants. Water and fertilizer were applied as needed. An Analysis of Variance (ANOVA) with Fisher’s Protected Least Significant Difference (a=0.05) was used to determine significant differences among treatments.

The addition of compost to the media used to grow tomato seedlings did not significantly affect seedling growth compared to using a peat-based potting mix alone. The media used for the seedling stage did not affect plant performance into maturity.

Compost moderately affected the overall growth and productivity of flowering stage tomato plants. The total fruit harvested in both years was significantly greater in plants grown in 15-45% compost than in those grown in peat moss alone. Plants grown with compost had greater overall root growth than plants in peat alone. Plants transplanted into peat moss alone were initially stunted compared to those with compost, though by the end of the growing season, plant height was unaffected by treatment. Shoot vertical density (g/cm) was greatest in plants with compost than those without. Overall, soil nutrients were low across treatments, but with greatest growth typically in tomato plants grown with 15-45% compost, additional nutrients supplied by the compost likely was a major factor in the differences observed. Based on these results, mature, food-waste compost, up to 45% can be successfully used to replace peat moss in greenhouse tomato production.

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