Band Steaming for Weed and Disease Control in Leafy Greens and Carrots

Nelly Guerra, Steven A. Fennimore, Mark C. Siemens, Rachael E. Goodhue

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Steam injected into the soil, raising soil temperatures to >70C for 15 to 20 minutes, will control weed seed and soilborne pathogens. The effect of this reduction in the weed seed-bank viability results in weed control in the treated zone that can persist for several weeks or months. The effect of steam pasteurization of soil on weed seeds produces results similar to a preemergence herbicide. In our study, steam was applied to the soil to control weed seed and propagules of Sclerotinia minor and Pythium spp. Replicated field trials in carrot, lettuce, and spinach were conducted using two types of band steam applicators in 2020 and 2021. Data collected were soil temperatures after steam application, weed control, hand weeding times, diseased plant counts, pathogen populations in the soil, and crop yields. Post-steam soil temperature intervals >70C in the top 10 cm of the soil ranged from 67 to 176 minutes. Steam reduced weed densities by 64% to 100% and lowered hand weeding times by 23% to 91%. The reduction of S. minor sclerotia propagules after steaming was 69% to 95% compared with the no steam control. The percentage of lettuce plants infected with lettuce drop was reduced by 60% to 70% and the reduction of Pythium spp. propagules in the soil was reduced by 50% to 100% compared with the no steam control, respectively. Lettuce head diameters in steamed soils were 10% to 24% larger compared with the no steam control. Carrots grown in the steam-treated soil had a 10% greater root diameter than the no steam control. Steam increased lettuce yields in two of three trials 22% to 28% compared with the no steam control. Gross revenues for the steam-treated lettuce were $3231/ha higher than in the no steam control. The data suggest that band steam is a viable soil pest control treatment for vegetable crops.

Original languageEnglish (US)
Pages (from-to)1453-1459
Number of pages7
Issue number12
StatePublished - Nov 2022
Externally publishedYes


  • carrot
  • disease control
  • lettuce
  • soil disinfestation
  • spinach
  • steam
  • weed control

ASJC Scopus subject areas

  • Horticulture


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