So, im getting conflicting information with promix hp running jacks 12-4-16 (hydro nutes).
Promix hp states on their website you should saturate untill to see a small amount of runoff. Basically the point of runoff is so you know you’ve fully saturated the promix hp and not to flush out the old nutes from the last watering. Then let the medium dry back before you water again.
I’ve been told you should water to runoff and that you shouldn’t because you would be flushing out the lime in the promix that controls the ph of the acidic peat moss.
I also have been told you should not go with the recommended ec from Jacks (2.3ec) and you should half it (1.15ec) because you are not watering until runoff.
Looking for advice from members that run Pro Mix HP with synthetic nutes.
Maintain mature plants at a runoff PPM of 1,000 (equivalent EC is 2.0.) This is standard and is independent of what grow media you are using.
Lime is a pH buffer, but it does not directly control pH. It takes much longer than the lifecycle of a cannabis plant for lime to break down and directly impact pH. You will have to adjust pH going in and monitor runoff pH and adjust as necessary, but shouldn’t have significant pH problems if using Jacks, as the mineral salt buildup is minimal with Jack’s products.
HP Promix has more perlite than their other mediums which drains quicker. The purpose of run off is to rinse the salts away that have accumulated from the previous feeding…you want this. Little to no run off will drive up the PPMs and creat PH issues. I would follow a drench to almost drought routine as in just an inch or 2 of the top is dry. PH range of 5.8-6.2
I’ve used (and like) Promix HP and have seen increased yields over coco/perlite. Like stated; using Jack’s you don’t have a salt buildup issue. Jack’s should be run at between 900 and 1,100 ppm for best results, depending on the plants.
Currently I run coco/perlite in Autopots with Jack’s 3-2-1 program. The last two grows I never flushed a plant, never checked runoff numbers etc. and had gorgeous 12 oz. plants. If you were using something like FF or GH you would likely want to do periodic flushes.
I use coco because it’s a renewable resource; unlike peat. Plus it’s way cheaper.
