I found 5# nursery pots for 50 cents each on craigslist...if you search hard enough you can find them for free from some nurserys...less work than the buckets, but either will work fine. Being in AZ white buckets should not be an issue, they may actually be better than black IMO.
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I also did some soil testing, and if you want to go with ready made...I like Kellogg, Cheap and made with quality ingredients. All organic if you're into that. I am still trying to make and test some of my own...but I gotta wait for my worms to finish thier work in the compost before I can begin...[/sub]
The light blue are in Kellogg...the others in some other cheap mixes. I have their names and can provide. Bottom line is that some soils are just plain toxic to peppers. They have all been repotted in the Kellogg soil now, but the ones circled in yellow are very slow to recover. Point is...you can find a bargain, but be careful because more often than not you get what you pay for.
yellow=supersoil TERRIBLE!!!
red=earthgro Not so great...but performed almost as well as MG
Blue=Kellogg REALLY GOOD! At $4.97 per 1.5 CF bag...its a bargain! Drains very well...the only issue I had was it is a bit "twiggy" Contains worm castings, bat guano, kelp...the list goes on premium ingredients for a bargain price.