Plant Exchange Blog

Yankton Community Gardens are located along the Marne Creek floodplain. Heavy rains caused flash flooding of the gardens in late June. The creek current extended into the gardens.

But by the next day, much of the water had receded or had been absorbed by the soil. Some pf the garden plants may continue to grow and produce. Concern about the possibility of contamination remains. Yankton Press & Dakotan article about the flood by Cora Van Olson is at this link:

http://www.yankton.net/community/article_76888d94-7e71-11e8-9409-0f58bd6d27b1.html?utm_medium=social&utm_source=email&utm_campaign=user-share

Below is the article referred to by the article and was released by Dr. Rhoda Burrows after the flood. More information is available at the South Dakota State University Extension website: http://www.igrow.org

Gardens after a Flood


Rhoda Burrows

South Dakota Extension Specialty Crops Specialist

Soil from gardens that were recently flooded may not be safe for fruit and vegetables production. South Dakota State University specialists said. SDSU Extension Horticulture Specialist Rhoda Burrows said depending on the location, flood waters may contain contaminants such as agricultural or other chemicals, as well as disease-causing organisms from fresh manure, septic systems, and even lagoons. Commonly found pathogens include E. coli 157, Listeria,Clostridium, Campylobacter, Giardia, and others. All of these diseases make people very ill and, in some instances, have long-term complications or may be fatal. For that reason, FDA rules prohibit the sale of any produce from flooded gardens (pooling within a field without entry of water from outside the field is not considered flooding.) The following applies to home or community gardens.

If there is a high likelihood of chemical contamination, produce from the garden should not be used this year. If the contaminants are known, the soil can be tested for those chemicals prior to next year’s planting. However, these tests can be quite expensive, especially if more than one type of chemical needs to be tested.

If there is a likelihood that the floodwaters contain runoff from feedlots, flooded septic systems, or other biological hazards, guidelines for the produce depend on whether it directly contacted the flood waters.

For the next six months, any produce that contacted the flood waters, or flooded ground, should be thoroughly cooked to destroy pathogens. Surface washing is not sufficient to remove pathogens, as they can attach themselves to produce and form a film over themselves that is very difficult to remove by washing or scrubbing the produce. They can also enter any cracks in the produce. Cantaloupe are particularly at risk, since the netting on their surface provides protection for the bacteria.

Remember that even if the garden was only slightly flooded, during heavy rains pathogens can be splashed onto produce such as broccoli or cauliflower whose lower stems were underwater. Replace any organic mulch, such as straw or grass clippings, that was contacted by flood waters.

Leafy greens that will be cooked, such as spinach, should be cut back completely and allowed to regrow before using. They then should be cooked thoroughly before consuming. Remove the blossoms and any fruit from strawberry plants exposed to flood waters. Any strawberries that are produced within in the next 90 days from these plants should be thoroughly cooked before consuming.

Gardeners sometimes ask about tomatoes that are produced after the flooding. To prevent possible contamination, the plants should be staked or caged to prevent tissue from touching the ground, and freshly mulched to prevent soil splash. Once this is accomplished, fruit that is produced from stems that grew after the flood may be safe to eat as long as the fruit does not touch any plant parts that were submerged or splashed on by the flood. If in doubt, cook the tomatoes.

Vining crops such as cucumbers and cantaloupe should be pulled and discarded. Summer squash, winter squash, and pumpkins should be thoroughly cooked. Root crops should be peeled and cooked thoroughly for the rest of the season (six months).

Always wash fresh fruits and vegetables before eating, with running water and using friction. The use of detergents or chlorine bleach is not recommended. Fruits and vegetables are porous and will absorb these chemicals.

Some sprays approved for use on fruits and vegetables are available and may be helpful in removing debris, dirt and some surface microorganisms. If the garden produce was flooded, however, follow these recommendations. Don’t attempt to make an unsafe flooded garden product safe by using a fruit and vegetable spray, chlorine bleach or other product.

All gardeners should use good personal hygiene practices. Wash your hands before and after gardening. Leave your garden shoes at the door and change clothing after working in a flooded garden. Avoid direct contact with flood waters, including the soil, as much as possible. Young children can be at a high risk for some foodborne illnesses. If a garden plot has been flooded, consider either not having young children in the garden with you, or take precautions to utilize good personal hygienic practices.