Question
Hello, I've got about 20 pepper plants currently. Thai dragon, cayenne, red chile, jalepenos (3), habeneros (3) Bell peppers (2) green, a yellow and an orange, Chiltepin (2), and a few I can't recall.  I was wondering if the reason my plants aren't growing very fast was because of the 1 gallon containers that I've transplanted the seedlings into from the ground, originally. They've been in the containers for about a month, after being in the ground for a month.  In the ground, they were constantly attacked and weren't getting enough sunlight. They have been doing better since I transplanted them, but now they've seemed to stop growing as rapidly.  The type of soil they're in is a mixture of 75% Miracle-Gro vegetable gardern soil and 25% dirt from the backyard, which is a little clayish but not HORRIBLY bad. I've watered them when they start looking a little dried up, and usually give them a quick little spray first thing in the morning BEFORE the sun comes up (especially if I know it's gonna be a HOT day). Should I put a cup or two of sand into the containers to help them drain?? Should I water less?? More?? Transplant them into 5 gallon containers?? Any advice would help alot??  I live in Livermore, California, which gets PLENTY of sun (it's been in the high 90's and 100's in the past two weeks).  Thank you very much for your time.

Answer
Water, water, water. Not just a spray, but deeply, to saturate the soil. If it will not get wet enough with a hose, try dipping them in a pale of water up to the top of the soil, and leaving it submerged until the bubbles stop. Don't fertilize them when it is hot, with liquid fertilizer. Use only time release fertilizer in the soil. It will not burn the roots.
I would not use dirt from the back yard. It is not sterile. I would use only the bagged potting soil. But I imagine the soil came with the roots when you dug them up. Add some polymer crystals to the soil to hold moisture. A small amount of wet peat moss, and steer manure will help as well. No sand. It will turn to cement. If they are root bound in the containers, then pot them up to the next size larger container.
They may have stopped growing because of the heat, or because they are adjusting to the new environment. Peppers generally like hot sun, but if they were in the shade before, and now in the sun, they may need some time to get used to it, and to the new soil.
Sounds like you are going to have a great salsa.