Lay small pieces of screen mesh over the draining holes in planting containers that are at least 8 inches deep and wide. Layer a 1-inch coat of gravel over the drainage screen. Mix a premium-quality, well-draining potting soil with equal parts sand and mushroom compost. Layer it into the pot.
Lightly water the soil to make it slightly damp in preparation for transplanting. Carefully turn the current herb pot upside down into one hand while firmly grasping the base of the herb plant with your other hand. Gently tug it out of the pot, if necessary (they often will just slide out), and set the plant gently into the new pot.
Water the herbs deeply and let the soil settle around the root ball. Add more potting soil on top, if necessary, to even it out with the top of the planter.
Place the pots in an area that gets at least four to six hours of direct sunlight each day. For large amounts of herbs, use fluorescent lights as a supplement. Keep them away from heating or A/C units, as well as cooking fumes or fluctuating heat in a kitchen.
Water the herbs deeply one or two times per week so the soil is moist, but not saturated. Do not to overwater the herbs.
Fertilize the plants once a week with a fish emulsion during the growing season. The amount you should apply depends on the type of herb you are growing and the fish emulsion variety. Work the fish emulsion into the soil around the base of the herb plant without directly touching the plant. Wear gloves when handling fish emulsion
Clip the leaves or sprigs very carefully with small, sharp scissors to harvest them. Don't cut away more than 1/3 of the herb plant.