Best time to water lawns is after midnight and before sunrise

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If enough people are interested, I am considering putting together a series of classes on fruit production in the Las Vegas Valley. There would be a fee associated with the classes, since participants would be required to purchase a textbook and other handouts will be provided.

The class would meet weekly for several weeks at our Life Long Learning Center at 8050 S. Maryland Parkway combined with workshops held at our Master Gardeners Orchard in North Las Vegas. Anyone who is interested in these classes can send an e-mail to morris@unce.unr.edu or call 257-5509.

Question: During spring of this year, I put down sod in my front and backyard. I purchased it locally, and I had the most beautiful lawn in this neighborhood. I have been having problems with brown patches of grass and then the area goes bare.

I was wondering if I may have a disease growing in the yard and if I should purchase a spray. I have pop-up sprinklers set for seven minutes at 8 p.m., seven minutes at 4 a.m. and seven minutes again at 5 a.m. for a total of 21 minutes. The sprinklers were installed by a friend.

Answer: Eliminate watering in the evening. This is a no-no for lawns. Instead, you need to water anytime after midnight and before sunrise.

This may not be what you want to hear right now, but the key to disease control is minimizing the stress to the lawn. The key to that in our climate is the irrigation system and its relationship to reducing plant water stress, which can encourage diseases.

The irrigation system is critical for the best looking lawn at the lowest possible water use. The heads should be installed precisely at the manufacturer's recommended spacing for your water pressure. If your friend did not install a pressure regulator on your irrigation system (most systems do not have them), I would highly recommend it. If you do not know what the correct spacing is supposed to be, I can find it out for you but you have to give me the manufacturer of the head and nozzle, and the type of nozzle (usually on the nozzle itself). I believe your water purveyor can give you the approximate pressure of the water delivered to your neighborhood.

Also, key to good performance is making sure that the irrigation pipe was sized correctly. If the pipe is not sized correctly for your irrigation system, your system may not be able to provide enough water to run your irrigation system efficiently. Determining the pipe size is more difficult after it is installed. Bottom line, the water from each head should reach the neighboring heads. You can see that when you turn on the system and watch where the water lands from each head.

Secondly, you should see very little fogging at the nozzles. You should see very little misting but the water should come out in drops that are thrown in a precise pattern from the irrigation head. This has a lot to do with the pressure and that is why a pressure regulator can be so important.

You have to check each irrigation valve that has sprinklers, not just one, since they all can be different. Without a good irrigation system, a lawn in our climate can be ugly and cost you a lot of money to maintain.

Treating for diseases when there is no disease, or if the disease is encouraged by an irrigation system designed and installed poorly, will cost you a lot of money down the road.

This is the time for many of our lawn diseases to appear so it is very possible. There are two probable diseases this time of year, summer patch and brown patch. It is impossible to know for sure if you have these diseases without sending it to a pathologist, which can take weeks. If this is water-related you are throwing your money away on expensive fungicides and also putting a pesticide on a lawn where people and animals may come in contact.

If you do buy a fungicide, look for one with a label that tells you it will control both of these diseases. Apply it exactly as the label tells you. Do not vary from the label in either applying more or less of the fungicide.

Q: Last year I quit deep watering pomegranates about Sept. 10. At this time, I gave the tree small drinks once a week. I had a lot of the fruit split. Should I not water at all? Can the tree survive for six or seven weeks without watering? This year, as you recommended, I pruned the fruit at or before it became golf ball size, but I still have some very small fruits.

To get bigger fruit, how many should be on a tree? We've had the tree for nine years, kept it pruned to about 8 feet and the main trunk about 3 1/2 inches in diameter?

A: Never stop watering your fruit trees after harvest. This is a very old recommendation and no longer holds true. Adequate irrigation after harvest is critical for developing next year's quality fruit.

We are watering pomegranates three times a week, deeply, about 30 to 40 gallons each watering. This will drop to twice a week when temperatures drop to below 100 consistently, around mid September. The same amount of water, 30 to 40 gallons at each watering, will continue.

Finally, about the first week of December, it will drop to once a week. When leaves drop we will go to about every 10 days and still the same amount of water at each watering.

Fruit size has much to do with the amount of water the plant is receiving during fruit formation. It also impacts the amount of fruit splitting in pomegranate, melons, tomatoes and others.

The primary reason for small fruit is plant drought. Fruit splitting is due to fluctuating wet and dry soils. You should keep the soil moist all during fruit production and into harvest. Even after harvest if you do not water your trees enough it will affect next year's production.

Get on a regular watering schedule, fertilize the trees in mid January and, if possible, mulch the trees with about 3 to 4 inches of wood mulch. Water these trees deeply and regularly.

The only pomegranate fruits I remove are doubles, fruits arising from exactly the same location. I will remove one of the fruits, not both. The others I leave alone. Pomegranates need very little thinning of the fruit. I remove next year's fruit during winter pruning.

Q: My question is regarding growing a macadamia nut tree in the desert. I haven't seen any for sale at the nursery, but they can be bought at Home Depot in Northern California. Can they grow here or is the weather too extreme?

A: Macadamias have similar growing requirements to coffee plants and mango trees, that is, basically frost free growing conditions. Macadamia's are planted and survive in coastal areas of California. Macadamia do not like the high temperatures of the desert and survive poorly under our conditions. Mature Macadamias will handle temperatures to about the mid-20s and are suitable for container growing.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension.