Quote:Do all fertilizer's kill soil? I think I made a rookie mistake a few tears ago. I used to buy mushroom compost and mix it into my garden beds. Well two years ago I filled one bed with straight mushroom compost. My peppers did great but nothing else seems to last in there?

Eric,


I'd have to see the analysis of the potting soil to give you a specific answer but I can hazard some general ones. You may have a few issues:


The purpose of potting soil is to provide more nutrients to your garden soil and some aeration to the delicate feeder roots. If you use 100% potting soil you're upsetting the intended balance. The first and most immediate problem is too much air around the roots, which will kill a plants straight away.


Secondly, you didn't kill any soil, you probably made it too "hot" to use farmer parlance. Plants grow optimally in a fairly broad spectrum of 30-ish nutrients as well as soil Ph and texture. You should see the ph of the potting soil somewhere on the bag, which will tell you if it's intended to raise or lower you're existing soil. Generally you want it right around 7 (neutral), and it only takes getting to about 5.5 or 8.2 to start screwing with the plants ability to grow.


The next issue is probably the macros. That's the NPK analysis or the little code on the bag that says 7-7-7 or 16-0-8. That's telling you how much Nitrogen, Phosphorus, Potassium your adding. It's telling you how many lbs of each macronutrient you're getting per 100lbs of the fertilizer. That should also be generally mated to your soil and plants and by using only the potting soil you're probably outside of the acceptable high range of one or all of the macros - in other words you're too "hot".


Tl/dr: mix some regular soil back in and you'll be fine.

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