Originally Posted by MrBungle
Good one moony, it's a good idea to get your water tested for alkalinity and mineral content from time to time... So you can adjust your nutrient profile accordingly
The gardener I learned from lived in the flats. I no longer remember all the the exact numbers but pH was 8.2, calcium was pushing 300 ppm and iron was pushing 450 ppm. Many others were elevated as well.
My home garden is in the hills and did not do as well using same nutrients and light schedule.
Testing showed 7.1 pH, 175 ppm calcium, 50 ppm magnesium, trace arsenic (among a long list of trace minerals), and no iron.
After adjusting nutrient percentages the garden began producing larger harvests and stronger plants.
Tap water from municipalities should not have that large a variance but it can be large enough to affect plant growth.