LIME INDUCED IRON DEFICIENCY IN YOUR HOME LANDSCAPE

LIME INDUCED IRON DEFICIENCY IN YOUR HOME LANDSCAPE Iron deficiency is the most frequent problem for ornamental plants in Eddy County, and New Mexico. The major cause for this is the high pH levels of our soils. Calcium carbonate or cliché builds up in desert soils because precipitation is and has been low for a long period of time therefore it does not leach below the root zone. Our soils actually have plenty of iron but it is insoluble and unavailable due to the high pH and calcium carbonate. Iron deficiency often is made worse by soils that are over watered, or very dry. Iron deficiency symptoms appear on the youngest, newest leaves. The area between the veins becomes pale yellow or even white know as interveinal iron chlorosis. Other nutrient deficiency such as zinc or manganese may look similar especially on Pecan trees. Native plants seldom show symptoms due to an ability to solubilize and absorb iron from high pH soil. How to correct this problem? Ideally the soil could be acidified but because calcium carbonate is a very good buffer this will not work for short term or long term. Adding elemental sulfur at 2 ounces per cubic foot of soil will help on some soils. This is about 1 pound per 10 square feet. This will not change the soil pH however. It does cause a complicated chemical reaction which end product includes calcium sulfate or gypsum which changes the soil structure. Chelated iron fertilizers are available in many forms, research at the Agriculture science center in Artesia indicate that Millers ferri plus Fe-EDDHA worked the best and Sequestrine Fe-EDTA work almost as well at correcting iron deficiency symptoms. Read the label carefully there are some products that say they are Chelated iron but only a small percentage of the iron is chelated. Other iron products were very short lived because they were easily tied up by the Calcium Carbonate. This research also showed that Iron sulfate (copperas) worked when combined with ammonia sulfate (24-0-0-24) fertilizer when applied at 2 to 3 pounds per 1000 square feet applied monthly. The product that worked the poorest in our soil types with high pH and calcium carbonate was Ironite and is not recommended for use in our area because of the high pH. Ironite does not work well in Eddy County. The most effective means of supplying iron is by spraying fertilizer on the plant leaves. This requires some skill and experience and I really don’t recommend home owner to do this. Mix ferrous sulfates at 1 oz per 1.25 gallons of water add a couple drops of Ivory dishwashing soap or other non-ionic surfactant. I have burned the leaves off of plants following label instructions here. I think it is due to our intense UV light. I personally do not apply iron to leaves. Spray this solution on the plant leaves during cool weather, early in the morning or late in the evening. Do not apply during hot dry days during daylight hours. Do not use a stronger solution then is recommended as leaf burning or drop will occur. It is better to make multiple application of a weak solution than one strong one. Spray on a small portion of the plant and wait a day or two to make sure it will not damage the plant. If the plant response in a positive manner after a few days from the foliar application, you may choose to go ahead and apply this on the whole plant. Although foliar iron application is very effective, it is not a permanent solution either. Iron will not move form an iron rich leaf to an iron poor leaf, so multiple application may be necessary as symptom reoccur, and new leave grow. Also iron won’t go to new growth. The same is true with soil applications. I mix Fe-EDDHA (Miller Ferrii Plus) in a five-gallon bucket and pour it around the drip line of the plants or down the row of the garden. We have plenty of lime in our soils DO NOT USE GARDEN LIME!! IT WILL KILL YOUR SOIL. I know it is sold in some garden centers, it should not be used except for sanitation of livestock pens. There are injectable products they are available; I try not to use these except in extreme situations when plant death is going to happen if you don’t. There are a few commercial applicators who will do this for you and have the expertise and training. Because you are wounding the tree it is important to be as sterile as possible. Iron deficiencies are more easily avoided then corrected. It is possible to avoid the problem through the use of the above product early in the season and routinely through the season. Trade names are used for easy of identification by the consumer. Subscribe to Eddy County Ag news at: http://nmsueddyag.blogspot.com/ Eddy County Extension Service, New Mexico State University is an equal opportunity/affirmative action employer and educator. All programs are available to everyone regardless of race, color, religion, sex, age, handicap, or national origin. New Mexico State University, U.S. Department of Agriculture, and the Eddy County Government Cooperating.