Water is one of the most important building blocks of life, but we have to face the fact that not all water is created equal. This is especially true when it comes to your indoor garden, and even more so in your hydroponic garden. Liquid fertilizers contain mineral salts and dissolved solids designed to feed your plants a balanced diet; however, as discussed in previous blog posts (http://fifthseasongardening.com/?s=flushing), excess salts in the water can negatively impact your plants and garden equipment.
Water, as we generally encounter it, has more in it than just H2O molecules. City water, for example, typically contains 250-700 ppm of chemicals such fluoride and sodium chloride – not to mention all of the other things that get flushed down the drain (think pharmaceuticals). This means there are 250-700 ppm of stuff in our water that often isn’t nutritious for plants.
We’re lucky here in Raleigh that our ppm measures 100 . . . today. So if we wanted to mix up a nutrient solution for seedlings (which only require about 250 ppm). Using our tap water, half of our solution would be the NPK and micronutrients they need and the other half would be useless (even poisonous) salts from the municipality. So you can see how important it is to know your water source.
City Tap water
Constantly varies in pH and ppm, and travels through miles of pipes before reaching your home. Although you can access a documented water report, there are many additions to city water that are harmful to beneficial microorganisms our gardens depend on. In particular, Chloramine has recently usurped Chlorine’s position and unlike its predecessor, does not dissolve out with time or aeration.*
Tends to vary as much as city water in pH and ppm and also gets flushed regularly with Chlorine/Chloramine. Often has more randomly dissolved minerals, not to mention potential contaminants from farms and other run-off chemicals.
Likely the worst type as water for gardeners, this water is “softened” by the addition of salts the water – exactly opposite of what we want.
Often less than 200ppm of salt, but expensive in the amount needed for our gardens.
Tasty, but the salt content is still present. Filtration systems (think Brita and those that attach directly to the tap) are designed to remove sediments and chlorine, not ppm.
Distilled water from a Reverse Osmosis (RO) system is about as good as it gets. This water is often less than 40 ppm and costs much less to produce than bottled water is to purchase. Even with regular upkeep, water from these systems is much cheaper than even 5 gallon jugs on sale – not to mention easier to deal with as it is already in your home (forget those grocery store trips).
*A little more for those who want to aerate or evaporate out chlorine in their water…don’t bother. Chloramines don’t evaporate or bubble out, and even if they did, you’d still have all the salt (ppms) in your water – which is worse than chlorine anyway. For the record, plants require trace levels of chlorine to maintain osmotic pressure and can handle tap water concentrations of it (we prove this in our stores daily). If you’re having problems you think are caused by chlorine, look a little deeper and consider salts.