When you aerate—by punching holes in your soil—you reduce runoff, increase fertilizer effectiveness and aid root growth of your grass. Aeration boosts water penetration, which reduces runoff on slopes and helps water and fertilizer nutrients get down to the roots.

Repeated aerations over time will help your lawn better tolerate heat and drought. Aerate at least twice a year, in spring and fall.
Thatch

Aeration also helps remove thatch—a layer of organic or partially decomposed organic material that is above the soil surface. Thatch becomes a problem when the production of biomass (leaf, rhizome and tiller material) exceeds the decomposition of older biomass. Using too much fertilizer is the main cause of this imbalance.

Some thatch layers can be so thick that grass is "scalped" when mowed, water does not reach the soil and fertilizers become ineffective.
How to aerate your lawn :

Buy a manual coring aerator for about $20 from a nursery or home-improvement store. These stores also carry easy-to-use rental machines. Use this to pull out small plugs of soil and thatch. Or, hire a landscaping company to do the job for you.

Moisten grass a day or two before aerating to soften the soil. If the soil is too wet, it will compact more around the holes. If it is too dry, the aerator will bounce off the sod.

Make two to three passes to aerate severely-compacted soil to its proper depth of at least 3 inches. Space aeration holes about 3 inches apart.

Leave soil cores on the grass after you aerate. Your mower will spread them around and back into the soil with the next mowing.

Lower your mower's height to 1½ inches to stimulate new crown growth. Fertilize in late-September or early-October with a balanced mix of nitrogen, phosphorous and potassium. Fertilizer not only improves turf quality, root growth and color—it also builds cold resistance into your grass. Fertilize once more in November to get your landscape through winter with style.

Lawns usually develop brown spots because of faults in the sprinkler system. Mixed types of sprinkler heads, blocked spray patterns, improper spacing and the system's pressure can all affect your lawn.

Check that your sprinkler heads are level to grade, perpendicular to the slope of the lawn and not watering sidewalks, walls or patios. If grass blocks the spray, trim around the sprinkler head or install a taller 3- or 4-inch pop-up.

If your lawn looks great except for stressed areas in front of the sprinkler heads, the heads are too far apart. A device called an undercut nozzle can help; talk to an irrigation specialist if you decide to change out the nozzle.

Watering-system pressure also can cause brown spots. If your sprinkler system mists or has excessive water, the pressure could be too high. If the sprinklers display short spray patterns and reduced coverage, your pressure may be too low.

Hand water brown spots until the area improves.

A plant's leaves provide the first and most obvious signs that something is wrong with your plants.

Here are some tips to help interpret what your plants are trying to tell you:
Dull or Bluish Leaves

Small leaves that are dull or bluish tell you plants are struggling for water. This is especially true in lawns. If your lantanas struggle to bloom, they're signaling for more water.

Wilted Foliage

Wilted foliage usually means the plant is short of water, but that is not always the case. Roots growing in soil that is too wet can also cause wilting. Plants stressed from overwatering often suffer from poor drainage. Dig down and find out if that is the problem, then drill holes to create drainage through the rooted area if needed. Overfertilizing or a misused herbicide will cause the same problem.

Brown, Dead Leaves

Leaves with brown and dead edges suggest excess salts in the soil, due to poor drainage or compacted soil, which is very common in our valley.

Dead leaves suggest the plant was stressed for water on a hot, dry, windy day. Dead spots on top of leaf centers, especially the exposed leaves, suggest sunburning. This happens when the plant is hot and stressed for moisture, even if just for a few minutes.

Dropping Leaves

Drying and falling leaves on the inside of evergreens indicate they are aging and giving up nitrogen to the younger leaves. You'll see this on olives, oleanders, pines and most evergreen bushes. It also indicates the leaves are not getting enough sunlight, or the plant suffered through a dry spell or shock after transplanting. As trees age, leaves do drop more.

Desert trees and shrubs, such as Palo Verde and Ocotillo, naturally drop their leaves to save water in extreme heat. If the stress worsens, expect overall twig and branch decay.

Yellow Leaves

Your plant is struggling for nitrogen if the older leaves from the bottom up are generally yellow. The rest of the plant is often light green. Plants absorb nitrogen in the form of ammonium or nitrate, but these nutrients readily leach away. Use a fertilizer containing nitrogen, then irrigate to move the nutrients into the root zones. Iron deficiency is a major problem.

Yellowing occurs between the veins of young leaves, and veins become a pronounced green. Alkaline soil strongly affects the uptake of iron. Use chelated iron as it is readily available. If you have a severe problem, use Iron 138, a chelated iron sold as Kerex. Chelates are organic compounds that protect the iron until plants use it.
Ask the Gardens experts for help

The Gardens at the Springs Preserve offers expert horticultural advice on plants and problems. Visit the Gardens at 333 S. Valley View Blvd. or check out the "Ask the Gardener" Web board on the SpringsPreserve.org Web site.
Seasonal Tips

Your landscape has different needs during each season. To keep your yard healthy year round, visit the Seasonal Tips section for advice on common plant problems related to each season.

Mulch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Top

Mulch, also known as "top dressing," is a protective covering used to protect plants. Placed around the plant, mulch reduces water lost to evaporation by as much as 30 percent. Mulch also helps plants stay healthy by preventing frozen roots and weed growth.

Mulch can be organic or inorganic, fine or coarse and, in some landscapes, it may even be rocks.

The benefits of mulch:

Helps drainage
Encourages root development
Improves soil by making nutrients more available to plants
Insulates soil and plants in winter months, while cooling the soil and reducing water use during hot summer months
Used as an amendment to improve soil at planting time
Decorative

Organic mulch

If possible, consider using organic mulch. Organic mulches are those that used to be living material, such as bark, wood chips, straw, leaves, grass clippings, compost, and pine needles. Nurseries have specially prepared mulches as well. Rocks, a good inorganic and decorative alternative to organic mulch, can get hot and should be shaded with water-efficient plants.

How to mulch

In cool seasons, use a layer of 1 to 3 inches of mulch, depending on your preferences. For best results, use your hands to spread the mulch and avoid layering mulch too thickly as it can affect plant health. Don't allow mulch to make direct contact with the plants, forming a ring about 2 to 3 inches around plants instead. This will help avoid disease problems. When finished, water down the mulch to give it moisture and help it settle into place.

Talk to staff at any local nursery or the experts at the Gardens at the Springs Preserve if you have questions. Done right, mulching will greatly reduce how much trimming or weeding you do in your garden, as well as provide very attractive groundcovering.

The Las Vegas Valley has a variety of soil types, including clay, sand and hard-rock caliche gives your plants an advantage by amending the soil with additives.

Native desert soil contains a small percentage of organic matter, which is needed to support beneficial microorganisms. Many of the nutrients needed to support plant life are missing. The pH or relative alkalinity of the soil may be high, limiting some nutrients we add through fertilizing.

Soil analysis

If you can, get a soil analysis to help you better outline your yard's soil additive needs. For advice and assistance, contact the University of Nevada Cooperative Extension at 222-3130.
Preparing the soil

Before planting or upgrading your landscape, reduce the soil compaction by rototilling. Add organic material to the depth of several inches over the entire site to be landscaped. This is more beneficial than adding amendments to only the area of the planting.

Add sulfur to reduce alkalinity. Incorporate light quantities of fertilizer as well.

Recent research indicates that most desert adapted trees and shrubs do not require the addition of organic matter in the planting pits. Organically-rich soils may create overly wet conditions, possibly resulting in root rot or premature plant failure. This is especially true for desert native trees such as Mesquites and Palo Verdes.
Fertilize fruit plants

Peak blooming season is in the spring, and the best time to fertilize fruit trees and grapes is the six weeks before and after they bloom. Fertilize in late winter or early spring for the finest fruit.
Leaf scorching and burning

Leaves usually are stressed for one of two reasons: improper watering or improper fertilization. Since both overwatering and underwatering can damage plant leaves, the best solution is to water deeply and infrequently. This allows oxygen in the soil, washes salts away and encourages deep rooting.

For most trees and shrubs older than three years, water deeply once every seven to 10 days (Run your drip system one to three hours to soak the root zone). Newer plants may need water twice as often until established. Add a layer of surface mulch 2- to 4-inches thick to conserve water between waterings and cool and enrich the soil.

Make sure you have the right fertilizer both for your specific plants and for the time of year. Some fertilizers release much faster in hot weather, increasing the potential for damage. Follow package directions exactly and err on the conservative side. Then, irrigate well to move nutrients to the soil.
Best time to fertilize and aerate your soil

Fertilize in late-September or early-October with a balanced mix of nitrogen, phosphorous and potassium. Fertilizer not only improves turf quality, root growth and color—it also builds cold resistance into your grass. Fertilize once more in November to get your landscape through winter with style.

Aerate grass in September or October as well. Compacted soils are all too common here. Aeration boosts water penetration, which reduces runoff on slopes and helps water and fertilizer nutrients get down to the roots. Aerate again in the spring. . . .. . . . . . . . . . . . . . . . . . . . . . . . .. ... . . . . . . Top