Transplant quality, as measured by height and dry weight, of cabbage (Brassica oleracea L. Capitata group) and tomato (Lycopersicon esculentum Mill.) was lower for plants grown in media containing sewage sludge compost with a high heavy-metal concentration (HM) than for plants grown in peat-vermiculite (P-V) or low-metal (LM) sewage sludge compost media. Compost source had no significant effect on transplant quality of muskmelon (Cucumis melo L.) seedlings. Marketable yield of cabbage, tomato, or muskmelon was similar regardless of the media used to grow the transplants. The concentration of Zn, Cu, Mn, Ni, and Cd were significantly higher in transplants grown in HM media than in those grown in LM media. With the exception of Cd, metal levels in transplants grown in LM media were similar to those grown in P-V. Transplant media had little influence on the heavy-metal concentrations found in either foliar samples or the edible portions of the crops studied. Heavy-metal concentrations in foliar samples of all 3 crops were lower than those found in transplants. The lowest concentrations were found in tomato and muskmelon fruit, and in cabbage heads. The Cd concentrations in edible portions were very low regardless of the source of compost in the transplant media, indicating that sewage sludge composts, particularly those low in heavy metals, can be used safely in the growing media of vegetable transplants.

Tomato (Lycopericon esculentum Mill.) and cabbage (Brassica oleracea L. Capitata group) transplants were grown in peat-vermiculite (P-V) or in media containing sewage sludge compost from either a residential, low metal (LM) or industrially contaminated, high metal (HM) source. The transplant quality (stem diameter, fresh, and dry weight) of plants grown in P-V and LM were similar. Transplants grown in HM media were small, less-developed, and exhibited symptoms of heavy metal phytotoxicity. The concentrations of Zn, Fe, Mn, Cu, Pb, Cd, and Ni in tomato and of Zn, Cu, Cd, and Ni in cabbage plants grown in HM media were significantly higher than those in transplants grown in LM media. The addition of peatmoss to LM media had little influence on media pH or the heavy metal concentrations in transplants. However, peatmoss lowered the pH of HM media and thus the concentrations of Zn, Mn, Cu, and Ni in tomato and Zn and Mn in cabbage transplants increased. Concentrations of Zn and Cu in tomatoes and Zn in cabbage were above phytotoxic levels.