Alaska Girl,
I've never heard of softening water for plants, and am not sure it's a good idea. Most of the minerals that make water "hard" are required by plants. The minerals being dissolved in water is how they absorb them. Unless you have a large surplus of some mineral in the soil, I wouldn't think it necessary or even beneficial. Most water softening equipment uses salt. Excess salt in the soil would be a bigger problem, and in some western states, it is a very big problem.
Rick

Here I am being a big know-it-all, Again! I'm thinking, Alaska Girl, that you have alot of available "fertilizer"
They call a late spring snow, "Poor Man's Fertilizer" late snowfall is good for the crops and helps everything green up.Snow contains nutrients and also a lot of moisture. And if that snow falls on ground that's not frozen, as it would be in late spring, then the nutrients and moisture in that snow can penetrate into the soil and actually do some good for the plants that will grow in that soil later on in the year.
It contains nitrogen of course and actually it contains more of that now than it has in the past because of acid rain. The content of nitrogen and sulphur and some other elements has increased over the last several decades and has been considered a problem in terms of acidification of soils. But, in soils that we use for gardens and lawns, usually there's a shortage of nitrogen and that input can be helpful.

We seem to be in agreement that softening agents are harmful to plants.

Hard water is high in mineral content; too high for good plant health. The nutrients and minerals that plants need should be in the soil, not in the water.

The amount of fluoride in normal drinking water is not high enough to cause problems for plants. However, perlite and superphosphate fertilizers are both potent sources of fluoride that should be avoided with fluoride sensitive plants, especially Dracaenas, spider plants and peace lilies.

Chlorine is also not generally an issue for plants in concentrations used in most drinking water. Chlorinated swimming pool water would be a problem.

Acid rain is a problem in certain areas of the country that are downwind from industrial areas that emit smokestack pollutants. It is devasting to local forests. If it is not a problem in your area, then collecting rainwater is a good source of water for plants. Filtered and distiled water are also good options.