Fartman - I was reading on pod racers thread that a "Ca:Mg 3:1
NO3:NH4 9:1" needed to be considered when making a formula for HP aero?
How close do i need to be?
I see now i am better off mixing my own and now i found your info i will when i run out of PBP,
all though i wondering if adding some PB original would effect taste when combined with the raw mix?
or if it really matters, I know when i used all canna it gave the bud a sweeter taste, than say the same strain in dirt with miracle grow?
but i am stuck with pbp, and need to read up more on your mixing info...
as always, thanks in advance.
Who is Fartman?? I don't know of a Flatulentman in this forum. 3 to 1 is about the acceptable standard for a calcium to magnesium ratio. Even if you raise your calcium and magnesium for budding it is usually at about those same ratios. It is OK though during budding to increase the magnesium and not the calcium. This is done by some to increase the EC and therefore transpiration when they already have a high concentration of Potassium. I usually keep my Aero SOG grow Calcium, Potassium and Total nitrogen pretty much at equal ratios. When calcium is used to raise the EC it usually decreases transpiration and therefore decreases nutrient uptake. Though this will lower humidity during budding and lessen mildew problems, I would rather have the higher transpiration and higher nutrient uptake and just control the humidity instead. Ift is very possible lowering the calcium might actually be more advantageous during budding in aero. This would mean lower the calcium by about 80 ppm and increasing the potassium by 80 to 100 ppm.
The higher calcium, magnesium and iron levels added through using Cal-Mag Plus are needed during budding because with a recirculating reservoir system more are locked out or tied up during budding by carbonate and precipitation so less are available. IE
There is not a higher plant demand for these nutrients. This does not happen with a drain to waste system. This decrease of calcium and increase of potassium should increase nutrient uptake and transpiration during budding with drain to waste systems. This lowered calcium would likely lower the nutrient pH in recurculation reservoirs. As HP aero is typically drain to waste the pH change of the waste water is more just a growers way of indicating what nitrogen source is being up taken and otherwise is of no real concern. With drain to waste the drain water pH does not matter in that there is no recirculation reservoir for it to effect. You do need to consider the differences between growing longer veg cycle plants (large plants) or SOG plants. Cutting the SOG plant calcium is not as not likely to be as advantageous as with the long term larger plants. SOG drain to waste aero plant calcium uptake seems to stay pretty consistent through out the grow until dropping in the last 7 to 10 days, where as the calcium uptake after the stretch stage in the larger plants drops quite a lot..
As far as the nitrate to ammonium ratios. I keep it down to less than 7% of the total nitrogen being ammonium. That means about a 1:14 ratio
max. More commonly though I formulate aero nutrients at about 5% which is just below a 1 to 19 ratio, IE 1:20. A 1:9 ratio is way to much ammonium nitrogen for an indoor grow especially aero) unless you are growing with low temperatures (50's or low 60's F) and low intensity lighting (fluorescent or CFC).