Even watering helps prevent split tomatoes

A: This is usually irregular watering: overly dry, then wet, particularly when the fruit is starting to ripen. Surface mulch helps to keep the soil evenly moist and helps prevent wide swings in soil moisture and subsequent fruit splitting. The surface mulch also helps keep the fruit off of the ground and prevent rotting.

Otherwise you will have to watch carefully when your tomatoes need moisture and not let the soil get too dry between irrigations. Drying soils help to hasten the maturity of the fruit and setting the “skin” of the fruit. Wet soil then causes the fruit to swell and the fruit to split when it begins to enlarge again.

Q: My once healthy and robust tomato plants are turning yellow and some offshoots are dying. What is the reason for this and is there anything I can do to restore them? They are still producing fruit.

A: This is the time of year we usually get some of the tomato blights. You should be feeding these plants when they are planted and again when they start to set fruit. This will help prevent the lower leaves from getting nitrogen starved as they are producing fruit. They need a boost of fertilizer after they start setting fruit.

Otherwise, if it is one of the blights, such as late or early blight, then a fungicide application may be in order. But, I would try to get that fertilizer application on regardless.

Another possibility is curly top virus, which causes yellowing, twisting of the leaves usually accompanied by purple veins and death. These plants must be pulled so they do not infect other plants.

I have sent you a picture of early blight, a disease common here. If this matches your problem, it will require a fungicide and a light fertilizer application. The Internet link, http://aggie-horticulture .tamu.edu/publications/tomatoproblemsolver/leaf, will take you to a disease diagnostic aid developed by Texas A&M University that might help you discover what the problem and solution might be.

Q: I want to know if you could graft a sliver of a neighbor’s peach tree to mine. My tree died between two and three years ago and came back as a sucker. It is an Elberta dwarf and is now 4 feet high.

A: Grafting requires some practice as it is as much an art as it is a science. If the sucker is coming from the very bottom it may be coming from the rootstock. You would be correct in that you could take a few buds from your neighbor’s tree and bud them into the sucker.

Even if it didn’t work the first time, it would be fun trying. Budding is normally done just as new growth is pushing in the spring.

Q: My husband recently passed away and I’ve now hired gardeners to do what he had done for years. I still have grass in my backyard and I’m not sure how often or even if the gardeners fertilize to keep it green as well as plants. I want to discuss this with them, but I’d like to have an idea of how often grass and plants should be fertilized and, perhaps when, here in Las Vegas.

A: Generally speaking you should be able to fertilize your tall fescue lawn a minimum of three times a year and perhaps as many as five times but no more than five. I generally recommend fertilizing Labor Day, Memorial Day and Thanksgiving Day.

It is probably best to use a recycling mower, sometimes called a mulching mower, so that clippings that have been mulched are returned to the soil where they decompose and add nutrients. This allows you to skip one entire fertilizer application.

The Thanksgiving Day application is important to help keep the lawn green through the cold winter months. You can usually apply about half of the fertilizer recommended on the bag if you are using a mulching mower. Certainly you should not be applying more than about three-quarters of what they tell you to apply.

Most fertilizer recommendations on bags are too high and cause a rapid spurt of growth in the lawn after an application. Applying too much fertilizer just causes excessive work because of excessive growth. Make sure they are mowing your lawn no closer than 11/2 inches and it would probably be best at 2-21/2 inches.

Q: I am so happy that my iris plants finally flowered this spring. One variety is yellow and the other is purple. They did not flower last year. I am attaching photos for your easy reference. I read in some article that the manner of cutting will determine next year’s blossoms. I need your help to know where to cut the stem now that the flowers are spent. Also, what are iris “increases?”

A: As the flowers are spent, you will remove the stalks that supports the flowers at a point where each stalk is hidden by leaves or all the way to the bases. The base would mean following the stalk all the way down to where it terminates.

I would assume that iris increases refer to the short rhizomes that are being produced by the mother plant. These short rhizomes produce clumps that are attached to the mother plant.

Every three to four years irises are dug up and separated. This means that these short rhizomes and daughter plants are removed from the mother plant. These daughter plants and mother plant are allowed to air dry in a protected and shady spot before they are replanted. Some people will dust the cuts with a fungicide to prevent infection. An iris needs to get to a certain size before it flowers. I hope this helps.

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 e-mail at morrisr@unce.unr.edu.