Too much of a good thing can be terrible

Water is essential to plant life, but what happens when there's too much of a good thing, as has been the case in many parts of the country and the world this summer?

Extreme rainfall is more frequent now, atmospheric scientists say, as storms form in an atmosphere made warmer by climate change.

In the garden, too much water can have fatal consequences, says Nick Goltz, director of the UConn Plant Diagnostic Laboratory at the University of Connecticut in Storrs, Connecticut. “Flooding deprives roots of oxygen, which leads to root-rot diseases, and then plants can't pull water up (and) through their leaves and vascular tissue.”

What you can do

Avoid walking on mud if your garden has been affected by flooding, and wait until the soil has mostly dried before assessing the damage. Applying any weight or pressure to wet soil can lead to compaction and press out even more oxygen from around struggling roots.

A plant with just a few symptomatic leaves may bounce back, but one that's wholly wilted probably won't, Goltz said, adding that plants with strong, deep roots – like trees and some perennials – have the best odds of recovery.

Annuals, which have shallower roots, don't stand much of a chance, he said, so they should be removed if they look unhealthy.

Plants weakened or stressed by flood water are more susceptible to pests and diseases, so keep an eye on them and treat problems as they arise, which could be months later.

Are fruits and vegetables safe to eat?

Flooded fruits, vegetables and herbs should be considered contaminated and not eaten.

“If the part you're eating touches the water, then it's unsafe” – even if washed or cooked – “because in addition to bacteria from standing water, runoff from nearby yards, pesticides, sewage and chemical contaminants” could be present, Goltz said.

However, if your garden was flooded but the above-ground edible portion of a plant was not, “then it can be eaten,” Goltz said.

“It's generally safe to eat an untouched tomato growing on a vine… (but not) a melon sitting on the ground. And even then, it's best to err on the side of caution by washing and cooking the tomato instead of eating it raw.”

If you're mourning your lost vegetable garden, Goltz says that “in most cases, it's fine to plant a short crop in soil that has been flooded.”