Husker Hort

A Nebraska View of Horticulture

Growing Safe Produce Following a Flood

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Use extra precaution to ensure safe vegetables this season. Image by Pezibear from Pixabay

We have been through a lot this spring.  We have had blizzards, floods, and everything in-between for weather including two bomb cyclones. It isn’t even May yet.  Now that the worst is over, we hope, find out what you need to do to have safe vegetables from your garden to eat this year.

Extra precaution might need to be taken in the vegetable garden this year, especially in flooded areas.  It is unknown exactly what flood waters bring with them.  If the garden area was under flood waters, there is a risk of contamination.  To be on the safe side, any area of the vegetable garden that was under flood water should be treated as if it was contaminated.  There are a few guidelines to decrease microbial risks in the home vegetable garden.  If the edible portion of the plant does not come in direct contact with the soil (tomato, pepper, corn), it is recommended to wait at least 90 days before harvest.  If the edible portion does come in direct contact with the soil (lettuce, leafy greens, carrots), it is recommended to wait at least 120 days before harvest.

What exactly do these waiting periods mean for this year’s crop?  If you have a perennial vegetable, like rhubarb or asparagus, you would need to wait close to 4 months from the time the flood water receded before picking or harvesting those vegetables.  This is because those vegetables come up through the ‘contaminated’ soil, potentially exposing them to microbial risks. That could mean not having a harvest from those crops this year because both are normally harvested early in the season.  Potatoes, carrots, and other vegetable crops that come into direct contact with the soil should also be harvested close to 4 months after the flood happened.  If you plant vegetables that don’t come into contact with the soil, tomatoes, cucumbers grown on a trellis, or peppers, then it is a 3 month wait from the time the flood happened to when you can safely pick those vegetables.  This year in those flooded areas, consider avoiding planting short season crops like spinach, peas, and radish.  If planted, there won’t be enough time for the waiting period to pass before those vegetables are safe to harvest.  This could result in those vegetables being over-mature and not good eating quality by the time the waiting period is over.

There are a few other steps that you can do to decrease the potential risk in the vegetable garden.  Mulching the vegetable garden is a great way to prevent the soil from splashing up onto the plants.  Mulch also helps in decreasing weed competition and maintaining soil moisture, which will be more important later on in the growing season.  This year, mulching will be all about decreasing contamination risks in flooded areas.  If your garden area was under water for an extended period of time, consider a different gardening approach this year.  Raised beds are one way to use the garden spot.  Raised beds can be built on the area, then can be backfilled with a potting media or a different non-contaminated soil source.

Also consider your water source.  If you have a private well, consider having it tested to make sure it passes drinking water standards.  Private wells should be tested on a yearly basis, but it is more critical now following a flood event.  Why test your well if you are just using it on vegetable crops?  If that water is contaminated and it comes into contact with the vegetable, it can contaminate the vegetables.  We wouldn’t want all of your hard work to go out the window.

If you are going to be working the soil this spring, make sure it is dry before you start.  Working or tilling up wet soil will cause my harm than good.  When wet soil is tilled, it damages the soil structure of the soil.  You will end up with big compacted masses, I call them clods, of soil that could take years to break up.  Your patience will pay off in the long run, give the soil time to dry out before working.

Taking precautions now before the vegetables are planted can pay off with healthy, safe produce this coming year.

 Elizabeth Killinger is the Horticulture Extension Educator with Nebraska Extension in Hall County. For more information contact Elizabeth at, her blog at, or HuskerHort on Facebook and Twitter.

Growing Safe Produce Following a Flood (PDF)


Author: Elizabeth Exstrom

A Nebraska Extension Educator out of Hall County with a focus in horticulture and sustainable landscapes.

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