Seasonal flooding in Connecticut impacts many, including residential gardeners. UConn Extension has collected information on flood resources and information all in one place at https://s.uconn.edu/flooding.  

Below are answers to some questions specifically pertaining to home gardeners: 

Can produce be eaten after a flood?

This is a very difficult question to answer, but the simplest and safest answer is a resounding, ‘No. You cannot eat produce from your flooded garden.’ Floodwaters may have come from pastures, sewage treatment facilities, and other sources of disease-causing contamination. 

Produce has too many nooks and crannies to thoroughly clean and disinfect. Cooking or preservation does not render it safe to eat. Fresh produce that was submerged by floodwaters should be discarded. Seeds and young plants are unlikely to survive being submerged by floodwater. You will observe discolored leaves and stunted growth, or plant death.  

However, if a flood occurs early in the growing season, it may be possible to salvage at least some of the garden produce. All produce that is consumed uncooked or raw, e.g., spinach, lettuce, cabbage, should be discarded. Soft fruits, such as strawberries and all melons must be discarded.  

Flood-damaged garden produce that is unfit for eating should not be preserved, including freezing, canning, or dehydrating. The recommended processing and cooking time may not be sufficient to kill pathogens.  

Early season crops that will not be harvested for 120 days and have not been touched by floodwaters may be safe to eat if cooked or peeled. It must be completely intact, with no cracks or bruises.  

If you are unsure if flood water contacted the produce, throw it out. Late-season vegetables that come from flowers produced on growth, that develop after floodwaters recede should be safe.  

Visit UConn Extension’s food safety program for more information. 

How long after a flood do I have to wait to plant? 

You can replant after the soil has fully drained and the top two to three inches of soil has completely dried. This may be up to 60 days. Plants that can be started later in the late gardening season, after the floodwaters recede, should be safe after an early spring flood.  

Cover crops can be established on flooded gardens to remediate the soil for the next growing season, rather than letting it lie fallow. When your landscape floods, be patient. Many plants will recover over time. Again, where edible plants are concerned, the safest response is also the simplest, “No! You cannot eat produce from your flooded garden.”  

What produce can be planted mid to late summer?

You can successfully grow some root crops, greens and other vegetables from late June, July or August plantings. It is important to know the average first frost date in your area. This will help you calculate when to plant these late vegetables so they will mature before cold weather damage.  

The Midwestern Regional Climate Center has produced an up-to-date calendar of first fall and last spring freeze dates. Some vegetables will tolerate some frost and keep growing even when temperatures are in the low forties. Others cannot tolerate frost and stop growing in cool weather. Bush snap beans mature in 45 to 65 days, but even a light frost (temperatures between 30° and 32°) will kill the plants. Kale takes just as long to mature, but the plants continue to grow when temperatures are cool, and can survive cold down to about 20°F.  

Cool-season vegetables, including kale and others in the cabbage family, may be the best choice for mid-summer sowing. An earlier-than-expected frost will not kill them before they are ready to eat. Many of the cold-tolerant vegetables actually have better quality when grown in cool weather. More information: https://homegarden.cahnr.uconn.edu/factsheets/succession-planting/ and  https://extension.umn.edu/planting-and-growing-guides/planting-vegetables-midsummer-fall-harvest 

Can you compost flood damaged plants?

Flood-damaged plants can be composted, but specific precautions should be taken. Composting is a treatment step which is necessary to make these plants eligible to be a safe soil amendment. While flood-damaged produce cannot be sold for human consumption, it may be composted and used provided that the composting process effectively reduces potential pathogens. The FDA’s Produce Safety Rule outlines standards for the use of biological soil amendments of animal origin (BSAAO), including compost. These standards require that composting processes are scientifically validated to reduce pathogens to safe levels.  

How should I treat my flooded lawn?

If your lawn is flooded in the early spring, turfgrass can withstand several days of submersion without serious damage. The damage is done by a lack of oxygen and light. However, later in the summer, when temperatures are high, ponding water can cause damage or even loss within a few hours, mostly due to high water temperature. Once the floodwaters have receded, pick up any debris from the lawn. This is essential as the deposited debris is a safety hazard to persons operating equipment, such as mowers.  

As soon as the lawn is dry, and this can take many days or even weeks, aerate it. If the soil temperature remained below 60°F and the water remained for four days or fewer, the turfgrass will probably recover. If the lawn was submerged for longer, repeat aeration in the autumn, and the following spring. Break up the aeration cores and over-seed in the autumn. Pre- or post-emergent herbicides may be needed to treat weed seeds that have come in with silt deposits.  

What effect does flooding have on trees and shrubs?

It is very difficult to determine the long-term effect of being underwater on trees and shrubs. Some woody plants tolerate wet soils better than others. All will suffer from a lack of oxygen when the floodwaters fill all the air spaces between the particles of soil.  

Usually, landscape plants can withstand being submerged for about a week. Remember that the waterlogged root systems may be affected by floodwater, even though the soil surface has begun to dry. This makes them susceptible to root-rot diseases. There is not much that you can do about flooded trees and shrubs except wait and hope for the best. Watch for signs of dieback: yellowing and dropping leaves.  

Just because the leaves drop, does not mean that the branch or plant is dead. Often the dropped leaves are a sign of stress and the plant will re-leaf later in the summer. Live stems and buds will have some green tissue–look under the branch bark. Remove limbs that are dead or physically damaged.  

Resources

Penn State Extension. Gardens after Flooding. https://extension.psu.edu/gardens-after-flooding 

University of Connecticut Extension. (n.d.). Produce from flooded areas. UConn Extension Food Safety. https://foodsafety.uconn.edu/produce-from-flooded-areas/ 

University of Connecticut Extension. (n.d.). The safety of food and water after a flood. UConn Extension Food Safety. https://foodsafety.uconn.edu/the-safety-of-food-and-water-after-a-flood/ 

University of Vermont Extension. (n.d.). Flooded produce: Frequently asked questions. https://www.uvm.edu/vtvegandberry/factsheets/Flooded_Produce_FAQ.pdf 

The information in this document is for educational purposes only.  The recommendations contained are based on the best available knowledge at the time of publication.  Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended.  UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.  The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider and employer.