Hibiscus plants can make lovely additions to any tropical garden, and the flower petals are edible. To get the most flowers from these tropical plants, they need to be fertilized regularly. Organic fertilizers are better because they don't contain harsh chemicals or salts that can alter the chemical composition of soil. A homemade hibiscus fertilizer will provide needed nutrients to these heavy feeders and keep the soil at the slightly acidic pH levels they prefer.
Fill a large bucket with a lid halfway with organic compost material or manure. Finish filling the bucket to the top with water. Punch holes in lid to allow air to escape, and place the lid on the bucket.
Allow the compost and water mixture steep in a cool, dry place, such as a storage shed, for at least one week. Organic material from the compost or manure slowly will leech into the water to create compost tea.
Strain out all solid matter from compost tea, using metal strainer, cheesecloth or pantyhose. When using fabric such as pantyhose or cheesecloth, stretch the cloth over the empty bucket and secure using twine or rubber bands before pouring the tea through the cloth into the bucket. Full-strength compost tea can be stored in clean milk jugs or other containers with lids.
Dilute the compost tea with water for use on plants, including hibiscus. Mix 1 part compost tea to 5 to 10 parts water. Use the less-diluted tea for monthly fertilization and the more-diluted tea for daily applications. Full-strength tea can burn plant roots or disrupt the microbes that live in the soil. Pour the diluted fertilizer directly onto plant roots or into a spray bottle for distribution to the plants.
Organic Liquid Fertilizer
Pour 1 gallon water into a large bucket or container. Add 1 cup undiluted compost tea and 1 oz. each of liquid seaweed, apple cider vinegar and blackstrap or dark molasses. The compost tea adds nitrogen and other nutrients, liquid seaweed provides plant hormones, vinegar raises the acidity of the soil and molasses feeds beneficial microorganisms in the soil.
Stir or shake the mixture to ensure all of the ingredients are blended well. Store in large containers or pour into spray bottle for misting.
Pour the liquid fertilizer over the roots when first transplanting hibiscus plants, and pour over seeds when starting new plants. Spray liquid fertilizer over leaves and stems regularly for maintenance feeding.