cheapest, yet reliable and dependable,,,,,about one acre garden
Cheap and water softening do not go together. Also, using softened water on your garden will kill it, too much salt.
Add salt solution to your water system and not to the garden. But they can be very expensive.
Softened water shouldn't be used to water a garden. Softened water contains salt. This salt can disrupt the osmosis that delivers water to the plants. I would get a standard water softener but split apart your water system so your garden water isn't softened. If you need to vary the pH in your garden, there are a variety of methods for doing this. Any garden center should be able to help you.
