What kind of garden are you growing? Orchard, vineyard, row crops...?
From the previous thread
here, you stated you have 1/2 Acre of farmland. You also stated that your well can provide up to 110 cubic meters of water per day. Assuming that you will need around 5 cm of irrigation water per week for the whole half acre, this works out to around 25 cubic meters per week. This amount of usage is still way above the capacity of "whole-home" packaged systems.
Your main 2 concerns of iron and tds content will require different treatment methods. Before you run the water through a reverse osmosis process, the iron and calcium/magnesium hardness must be removed first. If not, they will clog up the R/O system very quickly.
You said you had a water quality test done on the well. The figures that matter as far as i can tell are:
Total Iron (ppm Fe)
Total Hardness (ppm CaCO3)
Total Calcium (ppm Ca)
Total Magnesium (ppm Mg)
Total Sodium (ppm Na)
pH
Total Alkalinity (ppm CaCO3)
p-Alkalinity (ppm CaCO3)
TDS or EC(PPM/mMhos)
Please post values if you have them, as well as any other contaminants that exist in significant amounts.