Gardens that have been flooded may need repair

K-State expert says soil could be damaged after flooding

At a glance: K-State horticulture expert Matt McKernan says flooding can cause soil compaction and structure damage in home gardens.

More information: Matt McKernan, hortsupport@ksu.edu

May 28, 2026

K-State Extension news service

MANHATTAN, Kan. — Recent severe thunderstorms that have brought abundant moisture to parts of Kansas may have caused unexpected damage due to flooding in home gardens, says a Kansas State University horticultural expert.

“One major problem with gardens that have been flooded is the potential damage to the soil structure,” said K-State’s Matt McKernan. “When the soil becomes flooded, water fills in the air spaces depriving plant roots of necessary oxygen.”

An additional concern is the risk of soil compaction, which further restricts oxygen to the roots. The longer the flood conditions last, the more likely damage will occur.

“If water pools on the soil surface for a short period of time, there is often very little concern. Typically, if water recedes within 24 hours, the impact on plant health is minimal,” McKernan said. “However, when flooding occurs and water flows in from outside areas, contaminants in the flood waters may make it unsafe to consume exposed vegetables,”

Here are some considerations, but McKernan urges consumers to follow US Food and Drug Administration guidelines when deciding the safety of growing edible plants in flooded areas.

If crops have not been planted, determine if there is a better location to establish a garden where flooding is not a concern. Raising up the soil, even just a couple of inches before planting, will improve drainage and reduce flooding damage. For flood damaged soils, consider planting a cover crop instead to begin repairing the soil and protecting it from further compaction. Do not plant when soils are still saturated to prevent damaging the soil structure by digging, tilling and even foot traffic.
For established gardens where flooding occurs, leafy green crops and any fruit that is present should be disposed of due to the risk of contamination. Late season crops that develop after floodwaters have receded may be safe to eat, but the grower must evaluate the potential contaminants of the water.
With young crops, it may be best to replant if symptoms of stress appear, such as stunted growth and discoloration.

McKernan and his colleagues in K-State’s Department of Horticulture and Natural Resources produce a weekly Horticulture Newsletter with tips for maintaining home landscapes and gardens.

Interested persons can subscribe to the newsletter, as well as send their garden and yard-related questions to hortsupport@ksu.edu, or contact your local K-State Extension office.

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K-State Extension is a short name for the Kansas State University Cooperative Extension Service, a program that generates and distributes useful knowledge to support the well-being of Kansans. Supported by county, state, federal and private funds, the program has county extension offices statewide. Its headquarters is on the K‑State campus in Manhattan. For more information, visit extension.ksu.edu. K-State Extension is an equal opportunity provider and employer.