The problem is that there was a world shortage of Ammonium Nitrate last summer, the wholesale price multiplied by ten, and this was compounded by stockbrokers (the same people that brought the credit market down by selling and buying credit default swaps) descending on the Ammonium Nitrate market and trying to make a killing buy buying all the future production, thus forcing the price up.
Unfortunately, some resources are only in limited places, and a lot of those places are in China, who has decided it wants to use its rare minerals and metals rather than selling them.
Take Perlite. Its made from an ore. if you wind back the plate tectonics about 600 million years, when the coasts of africa and china were touching, there was a spot where the only source or perlite ore existed. The plates spread, and now there two main sources - yes, China and South Africa. The chinese mine makes 80% of the worlds perlite ore. And last year it closed while they did emergency repairs to stop the mine collapsing, so the worlds supply of ore dropped 80% and thats why now, when all the stored reserves have now been use dup, the price of perlite is about to go through the roof, unless the yget the chines e mine open again pdq.
Btw, ill give you all another tip - theres going to be a peat shortage this year. Stock up early, unless you want to pay through the nose for irish or german peat.