Plants’ greens may benefit from iron application

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The first of three indoor farmers markets supporting local producers will open downtown on July 14. This one will be on Thursdays from about 10 a.m. to 1 p.m. It is located just behind the El Cortez in the yellow building at North 7th Street and Ogden Avenue. At night it is known as the nightclub Azul. Free parking is available at the El Cortez. You can download a copy of the flyer at http://xtreme
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Q: I have several miniature bottle brush plants, some of which are a very pale or faded green as compared to the others. The red "brush" that is the flower seems pale as well. Do you think Ironite will take care of that? I used a liquid concentrate of iron and soil acidifier and that seems to have helped a lot.

A: Ironite may or may not take care of it. It may be a bit more of a deep-seated problem than just the iron alone and the Ironite may give the plant a temporary fix. Ironite increases soil acidity so that the iron in the product can be used by the plant. This will sometimes work depending on the situation but it is a Band-Aid approach to fixing the problem.

Because Ironite works only "fairly often," I hesitate to recommend it for that reason. It usually works best on woody plants when applied in late winter or early to mid spring. Applications at this time of the year of any product that adds iron to the soil may or may not work. At this time of the year you should focus on getting iron directly into the foliage. This requires spraying iron directly on the plant along with something that helps move the iron inside the foliage.

You might try some multiple applications of iron sprays combined with a liquid detergent or surfactant. The surfactant would be a liquid spreader/sticker . You may be able to substitute a teaspoon of Ivory liquid per gallon of spray solution. This may require perhaps five or six applications about a week apart to get some regreening. The number of applications varies from plant to plant. Some plants regreen easily while others are more difficult to regreen. Do this only when air temperatures are cool. There's also a chance of leaf burning on some plants so don't apply it hog wild.

A long-term fix focuses on improving the soil with amendments and using organic fertilizers. A better source of iron, but one that is more expensive, would be Sprint 138, which can be applied in late winter. I know that Plant World Nursery and Grow Well have carried it in the past. Although this is expensive, it goes a long way and usually requires only one small application of a few ounces per year in the early spring.

You might consider fertilizer sources such as Miracle-Gro, Peters or Osmocote applied a few weeks after growth resumes in the spring. These are good quality fertilizers that are not organic.

Try your Ironite first but I think it may be a crapshoot at this time of year. The liquid foliar iron can be just about any liquid iron and does not have to be the expensive 138 form. The 138 iron really works best if applied to the soil.

Q: I have an agave in the yard that shows signs of stress where the outer leaf starts dying from the tip and progressing back toward the base of the leaf. Is it lacking water? (I only water it once every two to three months.) Is there a nutrient that I can get for it and how often would it be applied?

A: Agaves and other cacti and succulents look better with improved soils and regular waterings. They don't like our unimproved desert soils but are very successful at surviving in them (even though they may not look very good).

Even though they are desert plants and do not receive much water in the desert, they will perform better and look better with more frequent waterings. Water about once every two weeks in the summer and once a month or less frequently in the winter.

They should improve unless they have other problems. If you plant more cacti and agaves, or replant this one, then make sure the soil is improved with compost at the time of planting. Adding compost to the soil surface will help but it is not as effective as putting it in the planting soil.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by email at extremehort@aol.com.