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pH and peatmoss medium question

Posted by kilabelle (My Page) on
Mon, Jan 8, 07 at 1:04

I am growing some tomatoes in a peat moss and perlite mix medium mixed with some lime (1 teaspoon lime per quart of medium)This will be my first soilless grow. The problem that I am struggling with is What does my pH of my nutrients need to be? I now that growing in water, the pH is lower than that in soil but I am not growing in soil nor am I growing in water. Do I feed them nutes with a ph for hydroponics or with a higher pH as for soil?

Follow-Up Postings:

RE: pH and peatmoss medium question

That will depend on your mix.. i know you told what it is, but I dont know how to grow in it. You should figure it out rather quickly based on your follage color maybe. I would shoot for 6.0 - 6.5 your range is ofcourse 5.5 - 7.5 but no need to feel the burn right off, work your way up. whats the medium testing at?

RE: pH and peatmoss medium question

You will want to adjust the Ph of the nutrient solution to 6.2 to 6.5 if you are growing in soil, especially if you want to get the benefits from using organics and beneficial micro-organisms.

Peat and perilite will act more like soil than hydro, especially if you add some worm castings and a little compost or guano.

The peat is acidic, so that would be one arguement to keep the ph a little on the low side (maybe 5.7 to 6.1) especially if you are using ONLY peat and perilite and providing ALL the plants food thru watering. In that case, the system will be working more like regular hydroponics.

RE: pH and peatmoss medium question

I use a promix soil. I use a 1 gallon bucket to measure my dirt, and mixed in a 10 gallon Rubbermaid Tote. I cut holes in the lid for air. I can cover it up till I need it and I can measure for consistency. For every 2 gallon promix I add 1 table spoon of dolimite lime, 1/2 gallon additional perlimite, 2 cup worm casing and 1/2 gallon Organic compost. Now, I'm sure you are wondering ok.. what about ph? Without the lime, the ph of this mix is 7.2-4. I know that because I use RO water to test it with. I mix the soil and let it sit 36-48 hours. I turn it every other day. Then before I use it, I take small plastic net pots and I set it in a bowl, and run my water over it. 3x Usually, the ph will get a little lower by last run off, but that is ok. 2-3 points won't matter. I add Dolimte Lime to the mix until I get a run off between 6.4-6.8. I let it sit another day ( I let the test soil dry well and add it back to the mix when done) I test a sample again. This sounds like a pain, but I now use 20 gallon totes, as I am repotting my plants every 4 months or so. The results are amazing. My house plants love it. But you can make as much as you want, and once it's done, the longer it sits, the better it is.
Now, the Nutrients ph needs to be adjusted between 6.4-8 and you are set. I use Fox Farm organic nutes. I get the ppm to around 400 and the ph to 6.5-6 for every watering. 2x every month, I folair feed my plants as well. ps. Add molases to your water. 2 tbl per gallon. lol.

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