The best way of fertilizing the soil is through compost fertilizers. They can be purely organic, if you know how to make them. Just make sure they're free from any chemical contamination. You can eliminate more waste materials in a practical way and add more life to your herb garden. So try composting. It's the best for your herbs.
The idea is to dig a hole in the ground deep enough to contain all your garden plant debris. Chop the debris for quicker decomposing and put them all into the hole. Cover with soil and let it sit there for 1 month or two. And then it's ready to use. It's fertilized soil and at the same time organic fertilizer. Use the soil for your herbs or plant something in the hole where the composting was done.
You may also add animal manure to your compost, like chicken dung. Or, add some of your biodegradable kitchen trash, like peels of fruits and discarded veggies or meat--like the innards of fish and fowl and the like. To prevent the trash from emitting an odor, make the hole deep enough so you can cover it with enough soil. It's easy, so try composting now and give your herbs and plants a treat. Organic fertilizer is a plant's ice cream treat, as it were.
A quicker way is to apply micro organism. Buy a bottle of organic micro organism, mix it with water, and spray over the trash heap in the hole. You may or may not cover it with soil, as the micro organism will prevent any foul order coming out from it. The micro organism will "eat" everything and multiply and quickly consume the whole thing within more or less a week. Then, your compost organic fertilizer is ready to use. This type is super powerful for plants and herbs, especially herbs and plants in the Philippines and Asia.
PhilAsian Herbs urges you to try composting. Be an organic gardener and help increase the organic food supply of your community. Fight synthetic processed food or the use of chemicals in food and farming. Let's start with ourselves. And it's good to know that you feed your family with only the best food--organic food grown right in your backyard.