sunshine mix #4 and a PH nightmare

[smoke_tayo]

i've used sunshine mix #4 amended with perlite and worm castings with much success in the past. using the lucas formula and watering with a ph of 6.5, i never had issues before.

this round i am noticing crumply crinkled leaves and spotting, which lead me to believe a ph problem. read a bunch of threads all over and found that others have a had ph issues with sunshine. it seems apparent that due to the nature of mass production, bales can come out being too acidic from the peat and not enough dolmite lime being mixed in.

with that in mind i did a little test. i watered plain at a 6.7 ph. run off ph came out at 5.4!!! then i tried my straight tap at 7.4 ph, run off at 5.8. i am such an idiot for assuming ph would be all fine and dandy.

i should have amended with dolmite from the get go and now i am kicking myself. i guess if i didn't trust how much perlite they add to the initial mix, i should of guessed there wouldn't be enough dolmite! thing is past grows have done great in this mix! guess i got a crap bale.

so before i attempt to fix this problem anymore, i was wondering your thoughts on what ph run off i should be aiming for and how?

i have always been under the impression that i want to hit 6.0-6.5 in soil/soilless. that said, should i be aiming for a 6.0-6.5 runoff and therefore ph UPing my water to 8sh ph to get those values? or should i add dolmite lime to the top layer and keep watering around 7? i don't want to do anything drastic. any and all advice would be appreciated!

 

[blahman]

Oh this isn't making me happy... I have 10 bales sitting in my shed ready to go for the next gro.

I use runoff as a general guidline for how acidic the soil is. You have to take into consideration what the ph of the water going in is, and how much it affects the water going out. But as you said a ph of 6.7 coming out at 5.4 would make the soil highly acidic. The larger the drop from in to out means the more acidic the soil is of course. I would try to raise the ph rather slowly large swings in ph aren't good. Try a good flush with your ph at 6.5-7 and see where your at. If your still very low, try adding a little lime , I would take it slow.

Since runoff and soil ph testers aren't very accurate i've gone to this method when something is off and I really want to find out whats up.
http://www.umass.edu/umext/floriculture/fact_sheets/greenhouse_management/phecpens.html

Of course its way more work, but your getting a very accurate ph.

 

[Albertine]

I have been fighting ph in Sunshine from the beginning, which wasn't all that long ago lol. This round seems to be much better. Too many variables as I'm amending with a lot of ingredients including more dolomite, and I have been raising my water ph into the high 7s with silica and kelp extract for every watering, and making sure not to flush as it seems to wash out the dolomite (fine powder) and make things worse. Rescue by potting up into fresh soil if you can. All this water that I amend seems to swing back into the 6s if I let it sit overnight - don't ask what's going on, I don't know, but haven't seen damage so far from using the higher ph water.

 

[smoke_tayo]

thanks for the help guys!

i ended up flushing like crazy then saw the problem return a couple weeks later. i think i have to make sure the it doesn't ever dry out too much because that's when i see ph problems return. what a pain in the ass!

i am never using sunshine mix again. its cheap and i've had great success in the past, but its not worth the potential ph problems. i transplanted into all mix which actually quotes ec and ph on the bag and so far so good. fingers crossed.

i need to go back to rockwool.

 

[emerald city]

we use promix,close to sunshine mix i believe....Ive found fert type must be compatible with water type/quality......And yes...those bales need to be mixed up ahead of time and checked for ph.The old bales that have set for long time can come out real acidic and need adjusting...We like ph 6.3 but have to set the ph of h2o/ferts at 5.8 or at the end of the cycle the ph will/could rise in the 6.6-7.0 to high ..needs to stay from 5.5-6.5...seen much better results at the lower end of the ph spectrum.......out/E.C