Our HVH Special Blend Fertilizer contains the minerals most hibiscus need in order to stay lush, green, and healthy. But under conditions of stress, poor soil, flooding or overwatering, or drought, your hibiscus' soil or potting mix may lose some of its vital nutrients, or your hibiscus may require extra high doses of them. If your hibiscus' leaves start turning yellow, and chlorotic, losing their glossy, dark green look, then you may have a mineral deficiency in your soil. The two most common minerals that hibiscus become deficient in are magnesium and iron. Both minerals are required in order for plants to build chlorophyll, the dark green pigment that makes leaves green. When either of these minerals is deficient, the plant produces less and less chlorophyll, and will eventually become quite sick if the situation is not remedied. For more detailed information about the use of iron and magnesium to prevent or correct chlorosis, see below on this page.
Iron
![]() Iron Chelate made with FeEDDHA |
To use as a foliar spray:
- Use 1 teaspoon of iron per gallon of water.
- Do not spray in direct sun. Spray in the evening, on a cloudy day, or move potted plants to a shady area. Iron Chelate can burn plant leaves if sprayed in direct sun.
To use in the soil:
- Make a small hole in the soil with your finger, put the iron into the hole, cover with soil, and water lightly to wet the soil.
- Use 1/4 teaspoon of iron for a plant in a 4" pot.
- Use 1/2 teaspoon of iron for a plant in a 6" pot.
- Use 3/4 teaspoon of iron for a plant in an 8" pot.
- Use 1 teaspoon of iron for a plant in a 2-gallon pot.
- Use 1 Tablespoon of iron for large plants in the ground.
Magnesium
![]() Magnesium Sulfate - Epsom Salts |
To use as a foliar spray:
Spray in the evening or in the shade, and follow the directions on the bottle.
To use in the soil:
- First water with plain water to moisten soil.
- Sprinkle magnesium on top of the soil under the plant
- Water lightly to wet magnesium
- Use 1 teaspoon of magnesium for a plant in a 4" pot.
- Use 2 teaspoons of magnesium for a plant in a 6" pot.
- Use 1 Tablespoons of magnesium for a plant in an 8" pot.
- Use 2 Tablespoons of magnesium for a plant in a 2-gallon pot.
- Use 1/4 cup of magnesium for large plants in the ground.
Order Magnesium Sulfate ~ Epsom Salts:
![]() Healthy, Deep Green Leaves - Rich in Chlorophyll |
How do Iron & Magnesium Help Plants?
When plants have a mineral deficiency, the leaves veins usually stay green while the rest of the leaves slowly turn yellow. This particular type of yellowing leaf is called "chlorosis," and is easy to identify. Chlorotic leaves can have other causes besides mineral deficiency, but iron and magnesium deficiency are the two most common causes, and two of the easiest remedies to try for leaf chlorosis.
![]() Chlorotic Leaves - A Sign of Mineral Deficiency |
![]() Chlorosis at the tips of branches in the youngest leaves is usually caused by a deficiency of iron |
Both Iron Chelate and Magnesium Sufate can be used as preventatives when there are no signs of chlorosis. To help maintain optimum health of your plant, use these products once each year in the spring, or twice each year in spring and fall.




