Last week I wrote about the use of gypsum to break up clay soil and how it is not true for Nebraska . There are other garden practices that also are not effective or only partially effective that I want to write about today. What prompted this article was a big advertisement in the Sunday paper from a store pushing “Season Long Grub Control”. They said to apply it now. I had seen these advertisements earlier and hoped no one would respond immediately, but this one was so big it really caught my attention.

          1. GRUB CONTROL: For regular readers of this column you know that the most effective time to put on grub control in Southeast and South Central Nebraska is after the 4th of July. Homeowners in the Eastern and Southern part of the country have to contend with the “Japanese Beetle”. Some have been trapped in Omaha and we have a few further West, but not like other parts of the country. The Japanese Beetle lays eggs, they hatch, and turn into a larvae (grub) in the spring so they have to put on grub control in the spring. Then again in August to combat the Masked Chafer Beetle that is our nemesis. The Masked Chafer grub turns into what we call a June Bug. So if you see lots of June bugs in your yard you are likely to have grubs to contend starting in early August.

          In organic gardening magazines and articles you may see the recommendation to use “milky spore” for grubs. This product does work on the Japanese Beetle larvae but is not effective on the Masked Chafer Beetle larvae. For good control of grubs, use a product that is recommended for this part of the country and apply after the Fourth of July. Be sure and water in within 24 hours with at least 1/2 inch of water.

          You may see some grubs in your flower and/or vegetable garden now as you are planting. These are the larvae of beetles and moths and are probably different than the ones in the lawn. The grubs in your lawn in May are big, fat, and lazy at this time and not doing any damage. They are just waiting to turn into June bugs and are not eating. It is the new small grubs that will hatch in August that really destroys our turf. Grub control can be applied now but for maximum effectiveness, wait.

          2. BLOSSOM END ROT: I usually put out my tomatoes after May 15th. This year is no exception as I didn’t even buy my tomatoes until May 15th. I do not like blossom end rot and other diseases that get on my tomatoes and other vegetables as most of you don’t. Blossom End Rot is the black spot on the end of the fruit is caused by a deficiency in calcium in the fruit. Advertisements will tell you to add calcium to the soil or to spray calcium on your plant. The soil in Southeast and South Central Nebraska has plenty of calcium. These recommendations may help some but I recommend that you save your money. What happens is because of irregular watering when the plant is young and starting to set on fruit. The calcium that is available goes into the growing plant structure and there is not enough for the fruit. If you want to avoid blossom end rot:

          A. Watch your watering and do not let the tomato plant dry out or get over watered. Disease and insects really like plants that are under stress. To avoid other diseases such as leaf blight do not overhead water. Blossom end rot is not a disease but a deficiency. Therefore the big black spot can be cut out and the rest of the tomato is ok.

          B.  Put newspapers between the cages to conserve water. The newspapers and/or mulch helps keep the soil from drying out and prevents weeds from stealing the moisture. When I prepared my two rows for growing tomatoes, I removed all the weeds, put down layers of newspaper between the large cages I have, and covered them with one year old straw that I was able to get at a very reasonable price. Compost and/or soil also works fine to cover the papers and thus keeps them from blowing away. I use at least 6 layers of newspaper. Since I pick up the coffee grounds from our neighborhood coffee house, when I have more than I need for my compost piles I will put the coffee grounds on the straw. This spring the area of the garden where my tomatoes were last year had hardly any weeds compared to the rest of the garden. I had lots of small tomato plants coming up where overripe fruit dropped off last year which I did not get it picked up, but few weeds. This year I am going to try and do the same newspaper and straw treatment with my squash and pumpkins and see if I have fewer weeds.

          C. When the plant is about 3 to 4 feet tall, remove the lower 8 to 10 inches of leaves and stems so disease organisms in the soil can not splash onto those leaves and infect your plant. The newspapers or any kind of mulch also helps avoid rain from splashing disease organisms that are in the soil onto the lower leaves.

          3. IRON CHLOROSIS: Many of our trees and shrubs, especially pin oak trees, quite often get iron chlorosis. The symptom is dark green veins in the leaf and lighter green tissue between the veins. This is also the symptom for deficiency of some other micronutrients. Advertisements in the paper and other publicity say to put iron (liquid or granular) on the soil around the tree or plant. Other recommendations include pounding iron nails into the tree. All of these recommendations sound as though they should work. There are two problems with these.

          1. We have plenty of iron in the soil in most parts of Southeast and South Central Nebraska. The problem is the pH of the soil. Research has found that as the pH gets to 7 or higher, micro-nutrients, especially iron, manganese, boron, and magnesium are more difficult for the plant to absorb and utilize. Thus adding more iron to the soil is ineffective. Most treatments by an arborist adds iron or other micronutrients directly into the tree or plant, or sulfur to the soil to lower the pH.

          2. Iron nails do not work as the iron is not in a useable form for the plant. The iron and the other micronutrients must be in a useable form the plant can use to be effective.

          If you have trees or plants that look chlorotic (have a yellow cast to the leaves) consult with your local County Extension Office for help and recommendations or consult a “tree expert” who is a certified Arborist or is a tree specialist with the Nebraska Forest Service, the Nebraska Statewide Arboretum, The Arbor Day Foundation, or with your full service garden center. 

Copyright 2010