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I use promix, but I keep my ph at about 6.3.
I treated it as though it were soil. My plants have all done great in promix for the 2-3 weeks.
When they're initially seedlings in rapid rooters is the only time I'll water with water ph'd below 6.0. I use 5.8 to be exact. Something I read about the slightly more acidic range being great for root development early on.
I've been using ProMix BX lately and the trick to avoiding pH problems is this:
Promix is stabilized at the packaging plant by addition of lime, a pH buffer (CaCO3). The pH of peat, the major component, is naturally around 5ish. The lime keeps the pH up above 6 UNTIL IT IS USED UP. This occurs because when you add water, you are allowing a chemical reaction (neutralization of the acids in the peat by the lime) to take place. Over time, the amount of lime left will drop, and this neutralization stops taking place.
Your job as the soilless ProMix grower is to keep ahead of the pH!
Typically you will start to see problems after about 8 weeks of the plant being in the same pot. This is because the lime is used up and the peat is breaking down into a sludgy peaty acidic swampy mess. pH will plummet.
So how do you avoid this? Simple!
Pot up into a pot that is JUST big enough for your plants. Time your grow so you are potting up into the next size pot, with fresh ProMix, every 5-6 weeks so that new root growth is ALWAYS going into nice fresh soil.
Staying on schedule, you should rarely if ever have to flush to keep your mix at the desireable soilless range which is about 0.4 pH points below the range for soil.
Good luck.
PH water and nute mix for pro mix or "soiless mix" at 6.3 its best... was told this from a very good grower from the old advanced nutrients forum... (damb it all for shutting it down)
Sounds like you got ahold of a bunk batch of promix. I been using it for years and I never had a problem like yours. It doesnt really matter what your ph is in the water your feeding the plants. It always comes out with a runoff in high 5's usually 5.8 everytime. I done several experiment tests even put in just straight tap water from faucet and it still gets a run off high 5's. On the bag of promix it only guarantees a 9 month shelf life once it is open and also if you are mixing your promix with water before you put into pot you have to throw out all unused left in the mix. The water activates the lime and cause the ph to rise. So only premix what you plan on using and never store the wet mix
Treat is as soil means treat it as soil, 6.8 ph. :mad:Quote:
Originally Posted by faceto27
You are treating it like hydroponic which is not treated as soil, 5.8ph. :cursing:
Since the question has been asked, and answered, about a dozen times I just thought I'd say the same thing again just in other words. :what: