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Are you watering with tap water?

City water contains chlorine and chlorine kills microbes – both good and bad.  Will watering plants with tap water kill the beneficial microbes delivered through compost use?

 

Chlorine, chloramine, fluoride, and salts are used to treat city and household water systems.  None of them are beneficial to plants, soils, or the microbial populations contained therein.

The good news is that if your city’s water system maintains chlorine at recommended levels, most plants won’t be harmed and soil/compost microbes will quickly recover.

Generally, chlorine also dissipates quickly.  Fill a 5-gallon bucket with tap water and let it sit for a day or two before using the water on plants.

Chloramine, a compound that includes both chlorine and ammonia, is a little harder on plants and soils.  It is used throughout the US, including a number of metropolitan areas served by McGill composting facilities.  Check out this list to see if your water system is among them.

Over time, chloramine use can acidify soil and damage plants.  If this chemical is running through your watering tap, keep an eye on soil pH.

Fluoride is added to drinking water supplies to strengthen teeth.  It is also found in some fertilizers and perlite.  Burned tips and edges of leaves can be a sign of fluoride toxicity.

Using compost to maintain a neutral pH will limit fluoride availability, as will switching to rainwater or filtered water.

Household systems designed to soften water using salts can damage soil and plants, too. 

Short of installing a new spigot in the H2O line before it reaches the water softener, adding calcium to the soil through applications of gypsum or lime can help.  So does simple leaching (over-saturating the soil to flush out excess salts). 

But know that leaching will also wash away nutrients.  If you opt for this method, be sure to add some compost post-watering to help rebuild the soil.

Collecting rainwater and mixing it with tap water can dilute the harmful impacts of chemicals and salts.

For home use, rainwater harvesting systems can be as simple as a $5 bucket sitting in the yard or as sophisticated as a $2500 tank set-up.

Just make sure water in open-top collection containers is not allowed to stagnate and become a breeding ground for mosquitoes.

Want more information about using tap water for watering plants?  We found this article that discusses the various chemicals used in water treatment and how they impact plants and compost.

FAQ: When is the best time to add compost?

Anytime is a good time to add compost.  Fall, spring, mid-season – every growing space can benefit from the boost of soil microbes and organic matter.

Is one timing option better than another?

A quick scan of gardening articles and blogs seems to indicate a slight lean toward fall.  Putting growing spaces to bed for the winter under a layer of compost and leaves gives soil microbes plenty of time to prep the ground for spring planting.

But incorporating compost a couple of weeks prior to seeding or transplanting at the start of the growing season works well, too.

No time to wait those extra 14 days?  Go ahead and add compost to the soil at planting time.  Just make sure that compost is fully mature.  (It should smell “earthy,” like soil from the forest floor.)  An immature product could compete with seedlings for nutrients or even burn young plants.  An unpleasant, ammonia odor is a telltale sign of immaturity.

If the compost at hand is still a bit too fresh, incorporate some air by turning with a shovel.  Dumping a bag onto a tarp or into a wheelbarrow will add air, as well.  Let it sit a couple of days, then check progress.  Keep “fluffing” the compost until it’s ready for use.

And don’t forget to add a bit of compost to container mixes, backfill, and other non-crop uses.  Follow manufacturer instructions, especially about amounts to use.  Depending on the feedstocks that make up the blend, some compost products may be richer than others.  Here’s the link to McGill’s use recommendations.

Most plants will welcome a little mid-season pick-me-up, too.  Simply sprinkle a little compost on top of a container’s soil layer, use as a side-dressing for row crops, or add a dusting over lawns.  Water in or lightly rake.