I haven't tried them but Fox Farm's fertilizers seem to work well for most people. At least, I haven't seen people using the correct NPK ratios with those ferts and have any major problems.
The are two general ways to go about fertilizers with soil. You can put nothing in the soil and feed them only teas or you can put as much as they can handle into the soil and wait for it to start running out. The first gives you more precise control over the nutrients the plants receive and the second is less work. We prefer the second so we can take a break from tea making once in awhile.
Making tea is just letting solid fertilizers sit in water long enough for all of their nutrients to dissolve and then filtering the solids back out. It's the same thing as making normal tea but poisonous to humans. We like to use a little heat and stirring to speed up the process. Take a pot and fill with water. Add your mix of solid fertilizers like Bone, Blood or Kelp Meals; Bat or Seabird Guanos; high-Potassium ash; etc. Put it on the stove at the lowest setting. Using a lid during the process will help minimize evaporation. Watch for steaming. If the pot starts to really steam, turn the temp down a little. Just a little steam is fine. Stir regularly, anytime you walk by, and let it cook for 6-8hrs. Then, turn off the heat and let it cool overnight or another 8-10hrs. It is ok if the pot sits for up to a day but after that there is danger of it going bad. In the morning, give it one last good stirring and then put it in the fridge until cold. A little bit more crap should fall to the bottom as it cools further. Once cold, get an old, high-threadcount sheet, fold it once or twice if it's big enough, wet it with plain water and drape it over a container. Either secure it with a rubber band or have someone help you. Pour the solution through the sheet, filtering out the insolubles. Add any liquid or easily soluble fertilizers that you don't need to make into tea to use. Add pure water until it reaches the concentration you're looking for. Finally, test the Ph if you haven't checked this particular mix before. Use immediately or refrigerate for up to 2 weeks. Some solutions can last longer than others.
When fertilizing your plants, always alternate feedings with plain water. It usually goes- wait for soil to dry, feed them the tea mixture, let soil dry again until at least the top third is completely bone dry, give them plain water, wait for soil to dry again, etc.
