RO (reverse osmosis) water is not typically recommended for watering plants because it is highly purified and has a low mineral content. The process of reverse osmosis removes many dissolved minerals and impurities from water, including calcium, magnesium, and potassium, which are essential for plant growth. Watering plants with RO water can lead to nutrient deficiencies in the soil and can cause stunted growth or even plant death.
However, if the plant species that you are growing are sensitive to mineral build-up and having high TDS water is a problem, or you live in an area where the water is high in dissolved salts, then it may be appropriate to use reverse osmosis water.
Another alternative is to use a remineralization filter that can add back some of the essential minerals removed during the reverse osmosis process, or to mix the RO water with tap water to balance the mineral content.
It's always recommended to check the water and the plant species requirement before using any water source for irrigation.