What Can I use as a soil drench to kill disease spores in garden soil?

Asked April 28, 2018, 12:01 PM EDT

I need ideas for chemical(s), fungicides, to use on my garden soil to get rid of soil borne disease spores that attack various vegetables, especially the green beans, etc., some kind of soil drench perhaps?

Someone had success using household bleach diluted 1part bleach to 4 parts water.

Vic Mitchell Carlton MN 55718

Carlton County Minnesota

1 Response

Thank you for the question. Drenching your soil with a bleach solution is not a good idea. According to The University of California Agriculture and Natural Resources, the active ingredient in bleach will kill some types of bacterial and fungal spores, but it is only effective as a surface disinfectant. It is not effective in soil, in fact, soil deactivates bleach.

While it is tempting to drench the garden with chemicals to eliminate all chance of disease, the University of Minnesota advocates a more nuanced approach where proper disease management consists of control methods not solely dependent on chemicals. Chemicals are used only when the disease has been identified and can be specifically targeted and all else fails. This approach minimizes damage to beneficial macro and micro organisms that are beneficial to soil health.
Non-chemical approaches consist of: Crop rotation, planting disease resistant varieties, disease free transplants and seed, garden sanitation and cleanup at the end of the season, using seed treated to resist fungal infections, solarization of the soil to kill harmful insects and organisms on the surface naturally, proper planting time, and fertilization. If disease occurs and is properly identified, chemicals are used as a last resort. This publication describes each technique in detail: https://content.ces.ncsu.edu/managing-diseases-in-the-home-vegetable-garden
Please review of publication on yard and garden diseases to familiarize yourself with techniques you can use to control diseases in specific plants this year: http://www.extension.umn.edu/garden/yard-garden/diseases/

Thank you for contacting Extension. If your plants develop a disease this year, try taking good, sharp, up-close photos and submitting a request for help to this forum. Good luck!