Most herbs require full sun and well-drained soil to thrive. Because of these factors, herbs will grow very well in Hawaii, a state that receives warm temperatures year round. Hawaii's soils vary in structure, but all of them are volcanic in nature. However, before planting an herb garden in Hawaii, you must first test the soil for nutrient loss. Nutrients leech out of Hawaiian soils quickly due to the frequent rains.
Select a location for your herb garden that receives between six and eight hours of direct sunlight daily.
Test your soil to determine the soil structure and nutrient content. The University of Hawaii College of Tropical Agriculture and Human Resources maintains a soil-testing facility for the purpose of providing fertilizer recommendations to Hawaiian citizens. You can contact your University of Hawaii community extension service for information on the preferred method of taking a soil test as well as how to submit it and fees that apply. Test results will be returned to you in approximately two weeks after you submit a soil sample.
Break up your soil with a rototiller. Remove any rocks, sticks or debris. Add fertilizer and organic materials to the top of the soil in the amounts recommended by the soil test results. Mix the amendments into the soil with the rototiller. Typical amendment recommendations for Hawaiian soils include compost, fertilizer and lime to increase the soil's pH.
Select tropical or Mediterranean herbs for your garden. Herbs such as basil, oregano, rosemary, sage, ginger, lemongrass, cardamom or turmeric will grow well in Hawaii. Herbs that grow in colder climates, such as coriander, may bolt to seed before you can actually harvest the herb.
Mound up hills for planting in order to help with drainage. Leave plenty of space between each herb plant to improve circulation and prevent mold in Hawaii's tropical, rainy climate. Plant seeds in drill holes twice as deep as the seed's diameter. Plant transplants by digging a hole for the roots, and placing the root ball into the hole. Cover the roots with soil.
Examine your herbs weekly for signs of pest infestation or disease. Pests or diseases that can affect herbs in Hawaii include root knot nematodes, thrips or fungal wilt. The University of Hawaii can recommend approved pesticides or fungicides that will not harm the environment.
Harvest herbs regularly in the morning after all rain or dew has dried off of the plants. Regular harvesting of herbs helps to increase their production.