Why can’t I find fertilizer that doesn’t say “slow release” on the bag?

“Slow Release” has become a marketing gimmick for fertilizer sellers.  They will all try to tell you that there product is “slow release” because in most consumers minds this adds value.  So they splash it all over on the front of the bag.  To really get the real truth, you should look carefully at the analysis label on the bag.  The truth lies within this labels information.  It will always disclose what percentage of the nitrogen contained therein is slow release.  The cheap fertilizers will say 20% or less of the nitrogen is slow release, but the more expensive types will say 50% or more is slow release.  The reason they are more expensive, is that they have to create some type of coating or mechanism around the fertilizer particles to slow down the distribution of the nitrogen.  We don’t want that, we want the cheap stuff for our purposes.  If the nitrogen isn’t soluble it will not be available to the bacteria and this will make the conditioning process happen more slowly.  Look for the least expensive bag of fertilizer, then double check the analysis tag and make sure it has 20% or less slow release nitrogen, or 80% or more soluble nitrogen.  Whatever amount of phosphorus or potassium is included doesn’t really matter much, as most of it will simply wash out, until we begin to build up soil particles in the bale.  At that point, usually day 10 in the recipe, the Phosphorus and Potassium will have something to bind with as it makes its way into the heart of the bale.

I like to use Ammonium nitrate or ammonium sulfate, but these are usually sold at the farmers coop, or farmers elevator and they come in a plain brown bag.  It is likely you won’t find these for sale at your garden center, but you could ask.  Otherwise, just go to the cheap lawn fertilizer section.  Do not use any fertilizer that contains herbicide.  Do not buy weed and feed.  Do not buy fertilizer with preemergent crab-grass-preventor.  Just buy plain old fertilizer, usually a store brand works great.

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