With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.

Growing vegetables in your garden can not only be a relaxing hobby, but also a great way to gain access to quality pesticides. When you’ve grown your own vegetables, you can be sure that they have not been exposed to pesticides or contaminants that could be lurking in the produce in the stores. Just like us, vegetables need water to thrive and survive, so the quality of water used in your vegetable garden is crucial. So, here we’ll explore which is the best type of water to use in your vegetable garden.

The Dangers of Tap Water

Most of us are aware of the water quality issues that can arise in our tap water. There has been a great deal of news in the media in recent years surrounding health issues caused by poor water quality. Even if your local treatment plant does a very effective job of treating your water supply, this does not mean that your tap water is the best for you and your garden.

While municipal tap water supplies are regulated, they can still contain contaminants that may create issues inside your home and in your garden. Most contaminants have an acceptable level, which has been deemed safe by the government. Unfortunately, even small amounts of some contaminants can have a devastating effect on your garden. Most municipal supplies are treated with chlorine to disinfect the water and kill bacteria, viruses and other pathogens. Once the water leaves the treatment plant, it may need to travel through kilometres of pipes to reach your home, so many facilities leave trace amounts of chlorine in the water to keep it safe. Unfortunately, this can leave water with a swimming pool like smell that can make it unpalatable. Even if you can manage the smell of chlorine in your water, a small amount of chlorine can have a terrible effect on your plants.

Additionally, there is often a moderate amount of sodium in tap water. This is approximately 200 mg per litre, which is far lower than the recommended daily sodium allowance in Canada at 2000 mg per litre, so it is not likely to cause permanent health damage. Unfortunately, when you’re drinking three litres of water a day, this adds up to 600 mg of sodium, just from your water. Obviously salt can also create problems for the soil in your garden and your plants.

Eliminating Chlorine 

The most obvious danger to your plants from tap water is chlorine. As discussed above, chlorine is frequently used as a water disinfectant. Although if this is causing some palatability  issues for drinking that will require a water treatment solution, if it does not affect your drinking water quality, you can easily eliminate chlorine from the water for your garden. You can quickly eliminate chlorine in your tap water, so you can water your plants without causing damage. You simply need to fill your watering can with tap water and leave it to sit for 24 to 48 hours. Over this period, the chlorine will evaporate to only leave trace amounts that should not impact the soil in your garden. This water can now be used in your garden to water your edible plants without any worry.

Hard Water 

If you have hard water, you may have considered installing a water softener. While this can be a great solution to improve your drinking water and protect your water using appliances, this can be detrimental to your garden. Most water softener models use ion exchange, replacing magnesium, calcium and iron ions with sodium. Although these trace amounts of sodium are not noticeable to the human senses, it can accumulate in your soil to cause damage to your vegetable garden. In this scenario, it is a good idea to have one tap, such as an outdoor tap that is not included in your whole house system. Experienced water treatment technicians will often advise keeping an outdoor tap outside of the softener treatment system to allow you to use untreated water on your garden.

Heavy Metals

If your water supply contains heavy metals such as lead, this can have a detrimental effect on your garden and may compromise your edible plants. These heavy metals can not only accumulate in the soil, but may also be absorbed by your vegetables. Many heavy metals are extremely toxic and should not be ingested at even low levels. So, if your leafy greens have absorbed lead or other heavy metals, it is not advisable to eat them.

In this scenario, you’ll need a water treatment solution to filter out the heavy metals. Fortunately, there are a number of treatment options that can eliminate traces of metals from your water supply.

Reverse Osmosis

Perhaps the best option to maintain your drinking water and the water you use in your garden is reverse osmosis. Reverse osmosis systems force water through a semi-permeable membrane to separate the water from 99% of contaminants. The pores in the membrane are so small that while water molecules are small enough to pass, most other molecules are not, so they are trapped and do not enter the treated water. This not only provides delicious drinking water, but also consistent water for your garden. Since most of the contaminants have been removed, you can add nutrients to the feed for your garden, tailored to the specific needs of your plants. This will allow you to enjoy the best of both worlds; great water for your garden and fantastic water for all of your water needs inside your home.

If you have concerns about your water quality and how it may be impacting your vegetable garden, it is a good idea to consult professional advice. An experienced water treatment professional will first test your water to determine the levels of contaminants that could affect your drinking water and the water you’re using in your garden. Once you have the water test results, your technician can guide you through the treatment options that are most appropriate to your specific water characteristics.