There are watering days and feeding days. Since RO or Distilled is pure water with nothing in it, no minerals, etc it is the best water to use to build the type of solution we want to use when feeding plants. But what about when we just want to water our plants? RO water tries to reclaim those minerals back by stripping calcium and magnesium from the roots of plants which is bad.
I have played with varying amounts of Bush Doctor Cal-Mag (2.5 & 1.25 ml/gal) for my water only days. The recommended amount is 5ml/gal applied at first signs of buds and apply not more than once per week, so I am obviously NOT following the directions. I do have an email to them about this issue as well. Directions do not address the type of water used and a search of the Fox Farm website has no articles addressing any use of RO water that I could find.
Although I have been playing around with this issue for a few years yesterday I found this How To Grow Cannabis With RO Water? - GrowDiaries
They suggest adding Cal & Mag until the PPM is between 100 - 150, which seems reasonable. Later when the plants start to bud I will provide that additional 5ml once per week.
I mixed 4ml/gal Cal-Mag worked out to 111ppm.
Anyone else see using RO water without adding Cal & Mag an issue, if so what do you do?
I grow autoflower plants only, indoors in a 3x3 grow tent. Plants are on a 20/4 light schedule and currently my new 2 Runtz girls 9 days old are getting 340 PPFD/30 DLI.
Happy New Year.