Watering Hibiscus In Containers & Fertilizing Plants

Question:

I have a hibiscus and a dwarf lime in pots on a patio with southern exposure. The new growth on both plants are very scraggly and the leaves look deformed. The dwarf lime has very little new growth. I’d let the soil dry out before I water either plant. Is there anything I can do to bring these two plants back to the lush growth they had when purchased last year? 

Answer:

Letting the plants dry out before watering them is a mistake.
  • You need to water more often as your plants are suffering from water stress. Hibiscus and Citrus like to be kept moist; otherwise,  they’ll continue to struggle and probably die.
  • You should be watering three times a week, more often with temperatures are in the eighties and every day when it’s ninety and above. The containers should be filled to the brim and then refilled a second time after the water has percolated through. The bottom of the container should be an inch or so off the ground. This allows air to circulate under the container and helps with preventing dry rot with wooden surfaces.
    • If it’s in a saucer, I’d still raise it up and be sure to remove any excess water later in the day. The concern with leaving the water is mosquitoes and West Nile Virus.
  • I'd feed them monthly with EB Stone Organics Citrus Food or Hibiscus and Palm Food or similar fertilizer. To avoid a fertilizer burn, water four hours before fertilizing and immediately afterward. Osmocote is a very good alternative fertilizer, as it’s only applied twice during the growing season.
  • With these changes, you should see dramatic results within six to eight weeks.
 

Question:

I've been fertilizing my plants with Magnesium Sulfate, Epson Salts, an Iron supplement and Sulfate of Ammonia. Will a buildup of the Magnesium be harmful to my plants and/or the soil?

Answer:

You're brave to be using Sulfate of Ammonia during the non-rainy season.
  • For many gardeners, Sulfate of Ammonia is a prelude to a disaster as they end up frying their plants from a fertilizer burn. Today, we have many other choices that are safer to use. Obviously, you know what you are doing.
  • But back to your question, you didn't mention the type of plants or how often you're applying this mixture so my answer is more general in nature than specific. It's not necessary to add Iron and Magnesium with every fertilizing. They’re both secondary elements so plants don't require tremendous amounts of either.
    • One application in the late winter or early spring is sufficient with a follow-up application in the fall.
  • The primary elements for plant growth are Nitrogen, Phosphorus, and Potassium also known as NPK. Sulfate of Ammonia is an incomplete fertilizer. It provides Nitrogen to plants but is lacking Phosphorus and Potassium.
  • You may wish to alternate your feedings with another complete fertilizer. That is one that contains NP and K.  Any of the general all-purpose plant foods would work.