Friday, September 27, 2019

When There’s Just Too Much Water…

Close-up of a white crocus flower in the rain
Hurricanes, flooding, rain for days, tornadoes, high tides, early snow, late snow, snowmelt – whatever is causing it, it seems that people everywhere are dealing with more water than anyone wants. Even here in Southern Arizona; this week we’ve been hit with days of heavy rain courtesy of Hurricane Lorena. For anyone who has cultivated property, enjoys their yard or lovingly tends a garden, bringing it back after it’s been underwater is not an easy process. What type of damage a flood causes and how to recover (if you can recover) can depend on many factors.

pencil cartoon of two people on the roof of a house with floodwaters all aroungd; one has an umbrella and is saying" At what point does it stop being goof good for the garden?" By RoystonWhere to begin: The only actions that can be taken while the water is still present are diversion or pumping it out, both of which can be impractical at best in an active flood situation. Plus, neither can reverse damage to soil that has already occurred if it has been underwater for 12-24 hours. It is best in general to stay out of floodwaters; they can be full of contaminants and creatures. Fire Ants, for instance, form rafts of many thousands of individuals to escape floodwaters and you do not want to bump into one of those!

Once the water is gone: If there is trash or tree and plant debris, you will want to get that out of your space. If you have flood-deposited soil, you’ll have to decide if it should be removed. Although as little as one inch of silt can kill a lawn and three inches or more can harm a tree, removing it may not be the best idea. Adding and removing soil can be very hard work, is quite costly, puts you in danger of handling contaminants and is damaging to the soil (more on that below). It might be best to simply scrape residue away from some of the bigger plants and start all over.

Close up a person in red and blue rain boots and jeans walking in the mud. Photo by Daiga Ellaby on Unsplash
Assess your soil: Whatever you do, do not work wet soil – it can cause serious damage to the soil structure. Wet soil can easily become compressed, which can lead to compaction and drainage issues when it dries. Wait at least several days to weeks before digging and if you plan to rototill, the recommended wait time is 90 days. You will want to determine how your soil biology held up to all the water. Soil microbes are an essential part to a healthy soil and they need oxygen. If the soil is submerged overly long, water displaces the oxygen in it and beneficial microorganisms can suffocate and die. Anaerobic microbes, which do not need oxygen, may take their place. A foul smelling soil is an excellent indicator that this has happened and that the soil needs to be brought back to a healthy balance before any planting is done.

Close-up of a green plant in clay pot full of water.Plant viability: How your plants are affected by flooding depends on many factors: length of time they were under water, what kind of plants and how old they are, time of year and the type of water that flooded. Warm weather flooding will affect plants more than flooding that occurs when plants are dormant in cold weather. Salt water will be much more damaging to most plants than will fresh water. Determining the condition of your plants can be tricky as symptoms can take weeks, and even years, to appear. Vegetables and flowering annuals will show symptoms before trees and shrubs. Damage caused by flooding mirrors common disease problems, so the root cause is often unclear. Here is a list of symptoms that appear in water damaged plants.

Vegetable gardens: First off, any produce that has gone through a flood should not be eaten. This is an EPA recommendation and it makes good sense. With all the unknowns in floodwater, it is the only way to be sure you are not ingesting contaminants. With fruiting vegetables, any fruit on them during the flood needs to be discarded, but whatever grows later should be fine. If you wish to err on the side of caution, wash those fruits thoroughly and plant a non-edible crop for a season.

Close-up of a white crocus flower in the sunWhat to do before replanting: As with all planting, start with your soil. A soil test is highly recommended after flooding.Water is notoriously good at leaching nutrients from soil, so even a minor water issue can affect what you’re planting in. If a soil test is not for you, you should still amend your soil and lightly fertilize (no heavy fertilizer while the plant struggles to come back). You can’t go wrong with the following products: Begin with TerraClean 5.0 to eliminate soil-borne pathogens; apply BioAct™ SD to chew through organic material; use products like ROOTBiojuvant® Beny-GroEarth Alive™ Soil Activator™ or Inocucor Garden Solution® to return to a healthy microbial balance; add Earthworm Castings and, when the new plants are in, fertilize with DTE™ Liquid All Purpose or SaferGro® Biomin Starter®. Fungal diseases are common after floods and they are best controlled by applying proactively; so get ahead of the problem and plan to treat as soon as you can. Check out our Fungicides page for some excellent products to choose from.

Like fungal diseases, flood damage is best dealt with before it occurs. I will offer some suggestions on how to do that in this blog next week. Until then, stay dry out there.

Submitted by Pam

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