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Hi...I am a new to gardening and plants. I live in Missouri and have city tap water. Would you suggest it is better to use a purifier or even distilled water? I have tried to research this and have found very conflicting advise. I just read that Spider plants are picky about water, but thought they thrived in most conditions? And are orchids and succulents more sensitive to what type of water is used? Thank you for sharing your wisdom!!!!!
Tap water should be fine, unless you have a water softener in which case you should not use it for your plants. In a perfect world you could collect rainwater and use that for them, but most people use tap water for their houseplants and they do just fine. When people have trouble with their houseplants it's typically due to overwatering, poor draining soil, etc not the type of water they used.
I water with tap water too, but that doesn't mean there aren't various issues associated with various water supplies. Most municipal water supplies have added base elements to raise pH so the water is easier on plumbing. This often means that the Ca level is also fairly high. Some municipal water supplies are also high in other nutrients or even chemicals that can become toxic at low levels, Na (sodium), for example. One of the biggest issues with tap water is the tendency for media pH to keep creeping upward, which causes many elements, mostly micronutrients, to form bonds with other elements and become insoluble/unavailable. The elements dissolved in water add to the level of total dissolved solids (TDS), which, if you aren't taking into consideration what those elements are and adjusting your fertilizer program accordingly (none of us [practically speaking] are), limits the amount of fertilizer you can use and increases the importance of using a fertilizer that supplies nutrients in as close to the same ratio as the plant is using them as possible. Using soils that don't allow you to flush accumulating dissolved solids from the soil for fear of the soil remaining saturated so long it impairs root function or causes root rot magnifies the issue, this, because ALL of the dissolved solids from tap water and fertilizer solutions remain in the soil, adding to the level of TDS. When the TDS level gets too high, it becomes difficult for plants to absorb water. TDS levels can rise so high it can actually reverse the flow of water into cells, just as curing salts 'pulls' water from meats like ham or bacon. As this occurs, it pulls the plasma from cell walls as cells collapse. This is called plasmolysis, or commonly, fertilizer burn.
All the above doesn't mean you should panic. As I mentioned, I water with rather high pH tap water and have healthy plants, but I know with certainty that if I didn't make some adjustments at certain times of the year for my water issues, my plants wouldn't be quite as healthy. In the summer, when plants are outdoors and I'm watering with a garden hose, all is pretty fine. In winter, when I can't so liberally flush the soil, I get some chlorosis from Fe (iron) being tied up by high pH. I correct this by adding white vinegar or citric acid to my irrigation water to bring the pH down to 5.0-5.5, which is a fine fix. I'm just glad I don't have to do that in the summer and water by hand, with some 250-300 containers to tend to. Rain water, water from a dehumidifier, or snowmelt are all good choices and relieve you of concern.
Spider plants don't like the fluorine compounds, so fluoride should be avoided as much as possible, but with spider plants, fluoride often gets hung with the blame that more rightly should be pinned on a high level of dissolved solids in the soil solution. The key to good looking spider plants is a soil you can flush every time you water, and frequent low doses of a fertilizer in a 2:1:2 or 3:1:2 ratio. Ratios are different than the NPK %s. I use Foliage-Pro 9-3-6 for virtually everything I grow. Other common 3:1:2 ratios are 24-8-16 and 12-4-8 - Miracle-Gro makes both.
If this leaves you with more questions than when you started, don't be bashful about voicing them. There is a 'sticky' thread at the top of this forum that you should find very helpful, too.
Some, but not many municipalities use a somewhat volatile form of chlorination in the water supply, so in a few cases some chlorine might gas off if water is left to rest overnight in an open container (pan/kettle/bucket). All other "chemicals and trash" (dissolved solids) would actually become more concentrated in the water left in containers as a fraction of the water evaporated. E.g., if you have a gallon of water with 1 gram of dissolved solids in it and a quart of water evaporates, that leaves the same 1 gram of dissolved solids in only 3 quarts of water, so the concentration of dissolved solids is actually 25% greater than before any evaporation occurred.