Edible Gardening

Growing Vegetables: The Importance of Water Quality

Water garden

While adding fertilizers and pesticides to your plants can amplify their growth, water quality remains the most critical factor in determining how well your home garden will turn out to be.

For plants, water is not merely a hydration medium but also a source of nutrition absorbed from the soil. If water is contaminated, the contaminants spread throughout the foliage and other parts of the plant.

While this may not be a problem for ornamentals, vegetables grown with contaminated water can pose a health hazard. In some cases, poor water quality leads to leaf discoloration, lower yield, irregular growth, and even plant death. Therefore, water quality is a pressing concern for growing edible plants.

Fortunately, if you’re on a municipal water supply, your plants will have access to tested and treated water. Since this water is safe for drinking, it’s also suitable for growing veggies.

However, if you use water from a rain barrel, pond, or well, it’s likely to be contaminated needing treatment before use. Meanwhile, recycled, reclaimed, or runoff water from a gutter also needs to be reconditioned before being used for irrigation since it contains soluble salts, disease organisms, and organic chemicals.

Let’s discuss a few common contaminants in household water that render it unfit for irrigation.

Soluble Salts

Electrical Conductivity is used to measure the presence of soluble salts in irrigation water. The standard amount of soluble salts in water should not be higher than 0-1.5 mS/cm – mS being milliSiemens per centimeter – since high salinity impairs root functions. Moreover, it also lowers the water uptake by the roots, leading to a deficiency of important nutrients in the plant.

Magnesium and Calcium

These salts indicate the hardness of the water. Although they’re essential for the growth of vegetables, salt concentration should not exceed the limit, which is:
• Calcium: 40 ppm to 100 ppm
• Magnesium: 30 ppm to 50 ppm

Sodium and Chloride

Water that comes from private wells, ponds, streams, and rivers is high in sodium and chloride. Besides, some other contributors of salts are roads, fertilizers, and water softeners.

Both kinds of salts are toxic for vegetables since they limit water uptake and cause growth reduction. Furthermore, a high concentration of sodium and chloride can lead to Foliar Chlorosis, which has symptoms similar to iron, magnesium, and nitrogen deficiency.

The tolerable concentrations of these salts are:
• Sodium: 50 ppm or less
• Calcium: 140 ppm


Sulfate is not a component of most fertilizers, but it’s imperative for a plant’s growth. The irrigation water should have at least 50 ppm of sulfate.

Potassium and Phosphate

These nutrients are meagerly present in water. If they occur in abundance in irrigation water, it points towards fertilizer pollution or other malpractices.

Trace Minerals

Trace minerals, such as iron, boron, manganese, copper, and zinc, are also called micronutrients. They may be present in water abundantly or in deficient concentrations.

However, the overall amount of micronutrients in water should be low since high manganese and iron content leads to damaged foliage, while an excess of fluoride also affects the leaves.

Impact Of Poor Quality Irrigation Water On Human Health

Chemical contamination of drinking and irrigation water is a health hazard in all parts of the world. Research has found everything from pharmaceutical waste to pesticides and microbes in irrigation water.

When you grow vegetables using this contaminated water, the chemicals and microbial impurities affect the plant’s product, entering our bodies through consumption. Here’s a table showing the health hazards of some common water contaminants.

Water quality chartSolution To Unclean Irrigation Water: Filters

Irrigation filters are a must-have irrespective of how clean the water is. Since it’s not a hefty investment, you should definitely consider getting water filters if you’re serious about growing your own veggies at home.

Whole House Water Filters for Well Water

Whole house water filters for well water ensure a safe supply of water for personal use and watering plants. We recommend you choose this option if you not only want to improve the quality of irrigation water but boost everything from shower water to water you use to wash your clothes.

Choosing The Right Irrigation Filter

Although many people realize the importance of having irrigation filters for growing vegetables, they’re not familiar with the process of choosing the best ones. Here’s a breakdown of the factors you must consider before buying an irrigation water filter.

Water Source

If the water isn’t coming from a clean supply, you’ll need a filter with a smaller pore size to ensure that it blocks all contaminants. Moreover, the filter needs to be cleaned every few days because it will be clogged by the debris in the water.

On the contrary, if you get clean water, an inexpensive smaller filter could do the job too. Although this water is comparatively cleaner, it still has small particulates that need to be filtered.

Plus, you should clean the filter screen every month to avoid clogging.

Emitting Device

You may also want to select an irrigation water filter depending on the emitting device. Do you use a sprinkler system, or does a drip tape water your vegetables? The mesh size determines how well a filter removes contaminants from water.

As a rule of thumb, a larger mesh number means finer filtration.
• Drip tape: 155 mesh
• Drip emitters and spray jets: 120 mesh
• Sprinkler sprays and rotors: 80 mesh

Mesh or Micron?

Both mesh size and microns indicate the filtration capacity of an irrigation water filter. Mesh size refers to the hole size of the filter screen. Simply put, it’s a measure of how many holes are in one square inch.

On the other hand, microns refer to particle size. For instance, a two-micron filter does not let any particle greater than this size pass through the holes.

Ease Of Cleaning

If you don’t clean an irrigation water filter, it will end up getting clogged and will not perform its function. In this case, having a filter is just as good as not having one.

Thus, you should select a water filter that’s easy to clean. Make sure you don’t have to disassemble the filter every time it needs to be cleaned. An exception to this rule is inline hose filters. You must disassemble them from the head assembly for cleaning. Other than these, most filters are easy to clean and require a few minutes to be just as good as new.

The frequency of filter cleaning depends on the water quality. If the water is relatively clean, you’ll only have to clean the filters every other month.


As is evident from many studies, contamination in irrigation water is directly related to human and plant health. If you’re watering your plants with chemical-filled water, it will not only stunt the plant’s growth but also be a health hazard for anyone consuming its produce.

Therefore, it’s important to measure the water quality before using it for irrigation purposes.

If you’re using rainwater or recycled water, make sure to pass it through an appropriate filter before letting your plants get their nutrition from it. As a result, the plant’s foliage and fruit will flourish while being safe for consumption.

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