For transplanting, it suggested fertilizing the new plant with a 34-0-0 fertilizer, however, I could only find 21-0-0 fertilizer. Should I increase the amount of fertilizer since it is not as potent?

When you transplant plants into the garden the best thing you can give them for a quick start is ammonium nitrate(34/0/0). Do not put anything on newly planted seeds. Fertilizer can inhibit the germination and even kill the tiny plants as they are emerging, so wait until they have come through the soil before you feed them at all.

However, if you can’t find 34-0-0, 21-0-0 will do them some good as well. If the weather is cold however, 21-0-0 does not work very well.