Just omit the lime. It is only used to offset the acidity of the peat.

It's also used to buffer the acidity of the bark. Some bark can be quite acidic.

Josh

I agree with Josh.

I use MG as my peat portion and still add lime.

I'd suggest you do the same with the promix.

I would certainly consider what you are growing before needing to make a lot of adjustments. I have never added lime to any of my mixes and have never noticed any adverse effects. But then I tend to grow plants that prefer things on the acidic side of the scale anyway (as the vast majority of plants do!)

You might find it interesting to review this previous thread from a few years ago that discussed this same topic and in particular, Al's responses :-))

When I use straight peat, I add about half normal lime for most of what I grow, which are eastern north American native trees (and other acid-preferring/acid-tolerant stuff) for eventual planting in the landscape. For other plants I do Al’s straight recipe.

I will be growing some lettuce and other greens, but also continuing my oaks, baldcypress, other acid tolerant and acid-loving stuff.