Some plant seeds, including cool season vegetables like lettuce and broccoli, germinate best in temperatures between 55 and 70 degrees F. (13-21 C.), while warm season plants such as squash and marigolds, germinate best when temperatures are between 70 and 85 degrees F.

As noted by the NSRC project, hot water can damage plants, leading to stunted growth or even death. According to gardening expert Ellen Brown of Sustainable Media, hot water has the potential to melt away the coating on a plant’s leaves or severely damage the plant’s cellular structure.

Effects of Cold Water Cold water can cause your plants to go dormant. Watering with cold water may send your plants into “winter mode.” They won’t die necessarily, but they’ll either stop growing or stop blooming. In general, keep cold water away from flowering plants.

between 62-72°F.

Most tap water should be fine for your houseplants unless it is softened because it has salts that can build up in the soil over time and eventually cause problems. Chlorinated water is also safe for most houseplants, but if you have a filtration system, that’s even better for your plants.

The product is called Start Right water conditioner which uses Allantoin, which is used as skin protect for humans, as well as in water conditioner for aquariums.. The product is safe for bacteria and plants…

Plants are able to absorb chlorine, but they only need very minimal quantities, and you shouldn’t ever need to add any. Watering or irrigating with tap water will over chlorinate your plants. Over chlorination will result in reduced growth and yields.

High levels of chlorine in tap water can damage your plants, some of which are more sensitive to the chemical than others. Leaves will yellow, and in extreme cases plants might defoliate. Chlorine also kills beneficial organisms living in soil.