Q. "Regarding irrigation, I found a couple of black “soaker” hoses (the type that basically weep out water) and tried them in my grow boxes. They worked very well for me as an irrigation setup for my grow boxes. I did wonder if the black color of the hose could heat up during hot sunny days and possibly “scald” the younger plants. A friend recommended slightly burying the hoses, but I felt I would have even more undissolved fertilizer if I did this. I appreciate any feedback".
A. Our experience with soaker hoses has not been as good as with drilled PVC pipe. Being right on the ground, and with VERY small holes, they tend to plug up and not deliver water from every orifice. Cost and durability are factors, and when used on dirt they get in the way of weeding and are susceptible to being cut in the weeding process.
Black soaker hoses will not burn or harm your small plants if used properly. They are supposed to be placed in the center of the bed between two rows of plants, and so will be several inches distant from plant stems.
Leaves should not come in contact with them, because you should always be pruning your leaves that touch the ground.
Lesson 16 of The Mittleider Gardening Course book will show you how to automate your watering in the best way possible.  Go to www.growfood.com/shop.