Photo: Robin Plaskoff Horton, Urban Gardens.

Update 2022: I wrote this post after Hurricane Sandy hit New York City area where I lived at the time. I now live in New Orleans where Hurricane Ida ravaged the city in 2021 on the 16th anniversary of Hurricane Katrina.

Many New York City gardens were flooded and/or damaged by Hurricane Sandy. In an effort to aid recovery efforts in and around the city, Green Thumb NYC, in consultation with the Healthy Soils, Healthy Communities Project Team, offers the following advice and recommendations for those with flooded gardens:

Five Post-Storm Community and Private Garden/Farm Tips
1. Do not eat produce from flooded gardens!
2. Flood waters can deposit germs (such as bacteria and viruses) on soil and garden vegetables.
3. Practice good hygiene (wear gloves, carefully wash hands, etc.) during and after working in the gardens.
4. Wait 30-60 days before planting in areas that have been flooded.
5. Soil testing is likely not needed, and results would likely be difficult to interpret, except in situations with visible chemical contamination (staining or sheen), significant sediment deposition or other unusual circumstances.

Photo via GrowNYC.

Compost Safety
New York State Governor Cuomo stated that flood waters can contain sewage and chemicals, therefore, “After a flood, throw out any medicine or food that has had contact with flood waters.”

As we reported in an earlier post, Jen from the NYC Compost Project at the Queens Botanical Garden shared some important information gardeners should keep in mind about compost and organic gardening:

1. If your plants have been touched by floodwaters, instead of putting them aside, you should not compost them, you should throw them away.
2. Organic soil that has been in contact with floodwaters, it is no longer organic. Anything that has been touched by the floodwaters will be contaminated with chemicals and should not be used.

Photo: Robin Plaskoff Horton, Urban Gardens.

Planting Vegetables After a Flood
According to the US Food and Drug Administration, specialists recommend a period of 30 to 60 days between flooding and planting and/or soil testing before planting. With the passage of time, anything deposited on the soil has been exposed to sunlight, rain, air, and other conditions. This reduces concerns related to microorganisms (for example, bacteria and viruses), which may have been present in the flood water and in the sediment left behind. Any chemical substances in the flood water were probably diluted and at low levels.

Chemicals such as gasoline and fuel oil that might have been released during flooding events are further reduced by sunlight, rain, air, and other conditions. In general, if you do not see signs of chemical contamination, such as staining or sheen, distressed vegetation, or notice chemical odors, then chemical contamination is not likely to be a concern.

Photo: Robin Plaskoff Horton, Urban Gardens.

Additional Resources
1. Consult the New York State Department of Health Disaster Recovery Information Bulletin for more information about what to do when flood waters contaminate your food crops and soil. Note: This bulletin is not specific to Hurricane Sandy and Hurricane Sandy’s floodwaters may contain more chemicals and contaminants than in typical flood water.

2. Green Thumb NYC, which provides programming and material support to over 500 New York City community gardens.

3. Safely Using Produce from Flooded Gardens, a fact sheet from University of Wisconsin Extension

4. For information about soil testing.

5. For a great general resource on urban organic gardening, visit former New Yorker Mike Lieberman’s blog, Urban Organic Gardener.