Reprinted from the K-State Research and Extension 2014 Newsletter, Number 28, July 15, 2014, page #1

          “Bearded irises are well adapted to Kansas (and Nebraska) and multiply quickly. After several years, the centers of the clumps tend to lose vigor, and flowering occurs toward the outside. Dividing iris every three to five years will help rejuvenate them and increase flowering.

          Iris may be divided from late July through August, but late July through early August is ideal. Because iris clumps are fairly shallow, it is easy to dig up the entire clump. The root system of the plant consists of thick rhizomes and smaller feeder roots. Use a sharp knife to cut the rhizomes apart so each division consists of a fan of leaves and a section of rhizome. The best divisions are made from a double fan that consists of two small rhizomes attached to a larger one, which forms a Y-shaped division. Each of these small rhizomes has a fan of leaves. The rhizomes that do not split produce single fans. The double fans are preferred because they produce more flowers the first year after planting. Single fans take a year to build up strength.

          Rhizomes that show signs of damage due to iris borers or soft rot may be discarded, but you may want to physically remove borers from rhizomes and replant if the damage is not severe. It is possible to treat mild cases of soft rot by scraping out the affected tissue, allowing it to dry in the sun and dipping it in a 10 percent solution of household bleach. Make the bleach solution by mixing one-part bleach with nine parts water. Rinse the treated rhizomes with water and allow them to dry before replanting.

          Cut the leaves back by two-thirds before replanting. Prepare the soil by removing weeds and fertilizing. Fertilize according to soil test recommendations or by applying a complete fertilizer, such as a 10-10-10, at the rate of 1 pound per 100 square feet. Mix the fertilizer into the soil to a depth of 6 inches. Be wary of using a complete fertilizer in areas that have been fertilized heavily in the past. A growing number of soil tests show phosphorus levels that are quite high. In such cases, use a fertilizer that has a much higher first number (nitrogen) than second (phosphorus).”





          “BLOSSOM END ROT” is a very common problem that can be prevented. Blossom end rot in tomatoes usually occurs on the first fruits of the season and may be seen on other fruits and vegetables such as watermelon, peppers, squash, and eggplants. The cause is lack of calcium going to the fruit.  It can occur even in gardens where there is abundant calcium in the soil. Most gardens in Southeastern and South Central Nebraska have sufficient calcium in the soil and additional applications, either to the soil or on the leaves (foliar), does not help stop the problem. Calcium dissolves in water and moves through the plant in the vascular system.  Under moisture stress the calcium goes to the leaves and stems thus is deficient in the fruit causing the blossom end rot. Rapid plant growth from over fertilization with nitrogen, and moisture stress from irregular watering are the two major causes of this problem.

          Irregular watering, especially during periods of fruit set, fruit development and rapid plant growth, seems to be the major cause of Blossom End Rot. Tomatoes need 1 inch of water per week during hot windy weather. One-half inch of water applied twice a week is better than one watering per week. Maintaining uniformly adequate soil moisture throughout the season is important.

          The second way to prevent Blossom End Rot is to not over fertilize. On any package of fertilizer you will see 3 numbers such as 10-10-10 or 32-6-4, or 15-30-15. The first number is always the percentage of nitrogen in the package. The second number is always the percentage of phosphorous, and the third number is the percentage of potassium.

          Nitrogen makes your foliage grow, so lawn fertilizer is high in nitrogen (24 to 36). Flower and vegetable fertilizer is lower in nitrogen and higher in phosphorous as the phosphorous promotes flowering, fruit development, and root development. If you have too much nitrogen in relation to phosphorous you will have beautiful big tomato plants but very few tomatoes. So do not put lawn fertilizer on your flower or vegetable garden. Potassium is vital for growth and good for hardiness and disease resistance. In summary, the second step in the prevention of blossom end rot and other plant diseases is “DO NOT OVER FERTILIZE!!!” 

          The third way to prevent not only blossom end rot but tomato blight is through the use of mulch.  Mulch can be straw, dry grass, leaf clippings that have been run through a mower, compost, or newspaper. I spread out newspapers, at least 6 pages deep, between my cages and then put straw, compost, coffee grounds, or soil over the top to hold them down. This mulch helps to conserve moisture and prevent the soil from drying out rapidly. Mulch also helps prevent the disease pathogens that are in the soil from splashing up onto the leaves.

          To prevent diseases in your tomato plants do not water overhead with a sprinkler. I put a soaker hose under the newspapers or mulch. If you have to overhead water, do not water after 2:00 pm in the afternoon. Many disease pathogens are in the soil and need a drop of water on the leaf in the cool evening to inoculate the plant. Therefore, water early so the plant leaf is dry going into the evening. You can’t prevent the rain but you can decrease the amount of disease by good watering practices. And, as mentioned above, mulch helps prevent disease pathogens from splashing up onto the leaf.

Copyright 2014