I often wonder why rain really perks up the veggies in my garden, but irrigation does not. There are a number of reasons:
- Rainwater carries small amounts of nitrate and ammonium formed in the atmosphere, giving plants a mild nutrient boost.
- Rainwater is naturally acidic, which unlocks trace elements from the alkaline soils that most properties have in Ellis County.
- Raindrops improve soil aeration by breaking surface crusts and carrying air into the soil, increasing oxygen around the roots. This is beneficial in supporting the roots, sending nutrients up the stem into the plant.
- Rainwater has no disinfectant. In Waxahachie, chloramine is used for city water except in October, when it is chlorine, as part of an annual system cleaning cycle.
See: Why Is Rain Good for Plants? The Science Explained – Biology Insights
Does the chlorine or chloramine in city water dissipate if I let it stand out?
No, at least for 11 months a year in Waxahachie. Each October, the city changes to chlorine as part of the cleaning cycle. However, for gardening, chlorine or chloramine in the water does not affect plants.
Why? Testing shows that some bacteria in the soil will be killed when irrigating, but it quickly comes back. You can, indeed, dissipate the chlorine if you let it stand for a couple of days. Chloramine must be dealt with by other means. It does not ever dissipate by letting it stand.
Do I need to dechlorinate irrigation water?
Chlorine and chloramine can temporarily suppress soil microbes, but the microbial community rebounds quickly. For most crops, this has no meaningful effect. The one exception is beans or peas, if you want to inoculate the seeds so that they can fix nitrogen.
There are several ways to neutralize chloramine:
- You can neutralize with an aquarium dechlorinator.
- You can add vitamin C. A pinch of powdered vitamin C should neutralize chloramine in a bucket of city water. See also: Using Vitamin C to Neutralize Chlorine in Water Systems
- You can trap rainwater from your roof. Just get a rain barrel with a strainer on top and a fitting for your gutter downspout.
So, happy growing and perky plants!
Aided by Copilot and Gemini AI, fact checked with Grok A
by Paul Thomas, ECMG