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Tuesday, June 17, 2014

Yes. You Should Fertilize Plants During the Summer

Many people believe you can't or shouldn't fertilize during the summer months. That is incorrect. Fertilizers are important to apply when plants need them, not according to the weather. The reason people are told not to is because fertilizers can be more dangerous to plants during hot summer months.

This is how you can and should fertilize during the heat. It is not magic. It is common sense.

 Ammonium sulfate can burn plants, is fast in its release and dissolves totally in water. I use it but you must be very careful using this fertilizer in the summer.

The major problems with fertilizing during summer heat is the combination of high temperatures and fertilizer salts. Salts in fertilizers can be damaging alone but in combination with high temperatures, they can be lethal. The amount of fertilizer you can safely apply is much higher in cooler months than in hotter months. You are not going to change the temperatures, but you can apply less fertilizer.

Rule No. 1. Apply less fertilizer during hot weather. 

Salts are all around us. They are in the food we eat. They are in the water we drink. They are in the soils we use to grow vegetables. Most organic fertilizers release fertilizer salts more slowly than conventional fertilizers. Not always, but generally speaking. So using organic fertilizers is usually a safer thing to do than using conventional fertilizers.

Rule No. 2. Use organic or slow release fertilizers during hot weather.

Fertilizer salts are salts. Salts can damage plants in two ways. First, drying out plant roots and stems through dessication or pulling water out of the stems against the desire of the plant to keep water inside the stems. Salt applied to living tissue pulls water out of the tissue. This type of damage to plants is much more severe when soils are dry. Never apply fertilizers to dry soils during summer months. When you are finished with a fertilizer application, water the fertilizer into the soil.

Blood meal is an organic fertilizer, safer to use than ammonium  sulfate but you still need to be careful.

Rule No. 3. Irrigate soils first. Apply fertilizer next. Then water in the fertilizer.

Fertilizers applied 1 to 2 inches next to the stems of plants can damage or kill. Salts in fertilizers pull water out of stems. If fertilizer is accidentally applied too close, don't panic. Either scrape it a few more inches away from the plant or push the fertilizer away with a stream of water and water it in. Apply fertilizers near the water source and no closer than 4 to 6 inches from small plants. Whether you think dry fertilizer landed on plant leaves or not, it is always safest to wash the leaves with water after a fertilizer application.

Rule No. 4. Keep applied fertilizer a safe distance from plants.

Temperature is important when fertilizing plants. Apply fertilizers in the cool morning hours or when there is a break in the summer heat.

Osmocote is a slow release conventional fertilizer but a safer fertilizer to use in summer months.

Rule. No. 5. Apply fertilizers to plants during the cooler times of the day.

How to Water Your Lawn During Summer Heat

I know that your municipality may have you on water restrictions in the desert. And that is good. We need to manage our water resources.You need to be aware of how to water turfgrass (your lawn) to minimize water waste and optimize lawn health.

These are key principles:
  • Sprinklers are designed to apply water when there is no wind. 
  • Wet grass encourages disease.
  • Winds increase after sunup.
  • Heat resistant lawns have deep roots.
  • Sprinklers apply water faster than soils can absorb it.
  • Water lawns when half the applied water is gone.
  • Most home lawns are tall fescue or bermudagrass.
  1. Water in the early morning hours before sunrise. Don't leave grass wet during the night time. This fosters diseases. When the sun rises, winds increase. Winds blow water "off course" and water is wasted.
  2. Apply enough water to penetrate 8 to 12 inches. After the irrigation is finished the water should wet the grass roots to a depth of several inches. This waters the entire root zone of the plant.
  3. Grass on slopes should receive an irrigation divided into several smaller applications. Most irrigation sprinklers apply water too fast. This water runs off the surface to low spots or into the street. Water delivered several times in smaller amounts has less chance or running off the surface.
  4. Irrigate bermudagrass less often but with more water than tall fescue. Bermudagrass can use 25 to 40% less water than tall fescue. It has deeper roots. It should be watered differently than tall fescue.

Texas Mountain Laurel a Good Desert Landscape Choice

Texas Mountain Laurel or Mescal Bean

Andrea Meckley, Certified Horticulturist
Description:  flowering large shrub or small tree
Mature size: 15-20 feet tall x 8-10 feet wide
Water use:  low to medium
Exposure:  all day sun to half day sun

Origin: Texas, New Mexico, northern Mexico
Caution: red seeds are poisonous
Flower:  purple sweet scented blooms early spring
Hardy:  0 degrees F

Texas Mountain Laurel (Sophora segundiflora) slowly grows naturally as a shrub or can be trained as multi trunk tree.  The poisonous seeds have a coat that is very hard and difficult to crack limiting risks to humans and pets if swallowed.  Native peoples used the seeds for ceremonial use and ornamental jewelry.  Use this plant as a hedge, screen or accent plant.

Sunday, June 15, 2014

Summer Flies. Or is it Summer Has Flies?

Normally Las Vegas is fairly free of flies. I guess the temperatures get up so high it is hard for them to reproduce. But not some.
Q. I can deal with the roaches and of course it’s a never-ending battle with the squash bugs but what is the deal with the flies?  Or is it just my garden? Seems they are everywhere but seem to like to stay in the relative coolness of my garden.  They have green heads and bite!  I’ve been hoping that they do the same job as bees and maybe pollinate the plants.  But I think not.  I can’t really spray for them and my bug-man can’t spray around food.  I’m even thinking about hanging fly paper.  

A.  There are a couple of flies here in the Mojave desert that look kind of similar. This is a blowfly which is quite common but it does not have a green head but a green thorax. Insects have three body parts; head, thorax just below the head and the abdomen. They can bite.

So of course they need water but they also are decomposers of meat, dung and raw organic matter that needs decomposing. Look for compost piles, garbage sources that have meat residues, etc. Might not be in your yard but a neighbors.

from wikipedia


Calliphoridae (commonly known as blow flies, blow-flies, carrion flies, bluebottles, greenbottles, or cluster flies[2]) are a family of insects in the order Diptera...

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Food sources (from Wikipedia)

Adult blow flies are occasional pollinators, being attracted to flowers with strong odors resembling rotting meat, such as the American pawpaw or dead horse arum. There is little doubt that these flies use nectar as a source of carbohydrates to fuel flight, but just how and when this happens is unknown. One study showed the visual stimulus a blow fly receives from its compound eyes is responsible for causing its legs to extend from its flight position and allow it to land on any surface.[10]
Larvae of most species are scavengers of carrion and dung, and most likely constitute the majority of the maggots found in such material, although they are not uncommonly found in close association with other dipterous larvae from the families Sarcophagidae and Muscidae, and many other acalyptrate muscoid flies.

Turfgrass Dead Spots. Irrigation Problem?

Brown spots or dead areas in lawns can be common during summer months. It might be a disease, but then again, it could be something else.
There is a sprinkler head in the center of the green spots.

The three primary reasons that lawns develop brown spots or dead areas are due to irrigation problems, the development of diseases and insect damage.

Irrigation Problems. How many times have I heard, “I know the sprinkler system was installed right. I did it myself.” Just because you did it yourself, does NOT mean it was done correctly. If it was done correctly did you design it for “head to head” coverage? Did you size your pipe taking into account all of your nozzles gpm and friction losses? Did you make sure the pressure of your 
First sign of an irrigation problem is that smokey-grey color in your lawn when it gets hot.
system falls within the manufacturers recommended pressure range for your nozzles? I can go on. If you understood these terms and took them into account then maybe you did it right.

Pressure too high. Sprinkler in the center of that little green spot of grass
Any weaknesses in your sprinkler system will show up when temperatures hit 110F and 15% humidity. Lawn water use will exceed 4/10 of an inch of water every day. The first thing you will notice when temperatures start to get hot are smoky-grey patches start to show up in your lawn. Then the brown spots or patches start to appear and they are often not clearly defined. Oftentimes they are smack dab between the irrigation heads when heads are not spaced appropriately, nozzles are mismatched, heads are not perpendicular to the lawn or you use 2 inch popups when you should use 4 inch. Sometimes these brown patches can be right next to the head if the pressure of your system is too high and the sprinklers “fog”. In order to clear up the problem or you use the wrong type of nozzles.

Little bit of drought and disease mixed in this lawn.

·       Know the operating pressure of your sprinkler system.
·       If mowing at two inches or above use four inch popup sprinklers.
·       Space sprinkler heads and select the right nozzles to provide head to head coverage (water from one nozzle should reach the neighboring nozzle and vice versa).
·       Size irrigation pipe to provide water flow through the pipe not to exceed 7 feet per second when operating.
·       Use a system pressure regulator (if operating pressure is to high) or a booster pump (if operating pressure is too low) so that operating pressure falls within pressure range recommended by sprinkler nozzle manufacturers.

Turfgrass Dead Spots. Disease?

Brown spots or dead areas in lawns can be common during summer months. It might be a disease, but then again, it could be something else.

The three primary reasons that lawns develop brown spots or dead areas are due to irrigation problems, the development of diseases and insect damage.

Disease Problems. In the hot, Mojave desert of the Southwest diseases are less likely than in wetter climates but they sometimes still occur. Most lawn diseases in our hot, desert climate occur when high temperatures collide with increasing humidity in the air. This is not the only ingredient for a disease to occur. The lawn must be susceptible to that disease.
Typical summer patch symptoms

Diseases problems are best solved through prevention. This is through managing the lawn to minimize diseases and using the correct fungicide when a disease problem is imminent.

We influence a lawn’s susceptibility to disease by how we manage it. Here are some management decisions that you can follow to reduce disease problems to your lawn. Try to implement as many as possible.
1.     Finish watering just before sun up.
2.     Mow at the proper height and use a sharp blade.
3.     Aerate two months before the heat arrives.
4.     Use compost-based fertilizers monthly.
5.     Disinfect mower blades if you mow a suspected diseased area.

When you suspect a disease is occurring, apply a broad spectrum fungicide (fungicide that treats many different diseases) as soon as possible. Diseases that should be listed on the label include summer patch and necrotic ring spot. They might also mention diseases such as “frog-eye” and Fusarium patch.

Turfgrass Dead Spots. Insects?

Brown spots or dead areas in lawns can be common during the summer months. It might be a disease, but then again, it could be something else. Could it be insects?

The three primary reasons that lawns develop brown spots or dead areas are due to irrigation problems, the development of diseases and insect damage.

 Insect damage. Probably the least likely of the three, and the most easy to detect, is insect damage. Most of the lawns in the Las Vegas Valley are turf-type tall fescues. Tall fescue is not a sod forming grass like Kentucky bluegrass. Instead, each seed produces a single plant. These individual plants are not linked together like they are with Kentucky bluegrass. Kentucky bluegrass sends out rhizomes, or underground stems, that pop up a distance away from the mother plant. When these rhizomes grow together, they form carpet-like sod that holds together. Because tall fescue produces only one plant for each seed that was planted, individual plants are not linked together.
White grubs feeding on lawn roots of sod
            This is important when diagnosing damage to a lawn. Insects that feed on the roots of lawn grasses, like white grubs, will cause areas of dead or brown grass. Because the mother insect lays a lot of eggs in one area, insect damage is usually localized in one or two areas. The eggs hatch, the young grubs begin to feed on grass roots and the lawn develops brown patches that correspond to where the grubs are feasting. The roots are severed by the grubs and the grass cannot get enough water so it dies in patches during warm or hot weather.
One type of an adult of the white grub
            Insect damage by grubs is usually in spots that are fairly well defined. Because the roots are severed, the grass can be lifted from the soil quite easily. Because tall fescue are separate, individual plants the root-severed, brown grass lifts easily from the soil. In the case of tall fescue, the grasses lift from the soil in the independently and separately from each other. In the case of a sod-forming grass like Kentucky bluegrass, they do not. Because they are linked together, the damage area lifts like a carpet.
            When inspecting a lawn to determine if the damage is from insects or not, go to the edge of the damaged area, not the center of the dead spot, and pull on the grass plants lightly with a closed hand. If grubs causes the damage and it is tall fescue, many of the plants will lift easily in your hands; dead ones and green ones at the same time that were recently severed.

Homemade Recipe Weed Killer From Reader

Q. A friend gave me the following recipe for homemade weed killer.
                 1 Gal.  Vinegar
                 2 C Epsom Salts
                ¼ C Dawn dish soap—blue original
            Spray on weed in the morning after the dew is gone.  Be sure to wash the sprayer well after us because vinegar ruins the rubber gaskets.
            My husband says that the salt could leach into areas that we don’t want to kill.  Also, will the above recipe kill all it comes in contact, grass and broadleaf weeds? I would appreciate your thoughts on this. 

A. I am not sure it will work but give it a try. The Epsom salts is a safe salt to use, not like table salt which is more like what your husband is thinking about. Table salt is sodium chloride. Both the sodium and the chloride are toxic to plants and the sodium in particular can cause longer term problems with the soil. 

Epsom salts is calcium and magnesium carbonate salts. Safe for plants and used on roses by lots of Rosarians. My experience with vinegar as weed killer is that the acetic acid has to be above 15% which is hard to find.

Who Stole All My Almonds?

Q. Our almond tree was full this year. However, half of our crop was eaten by something. The nuts are not ready yet. They are still green and so hard you would need a nutcracker to crack the shells open. My husband picked the rest of the almonds so we at least had something to enjoy. Any ideas as to what's eating the nut and cracking them open?

A. This is most likely ground squirrel harvesting. Technically I think they are called antelope ground squirrels and they are very common in southern Nevada. We find them typically at residences near or bordering the desert or large expanses of desert landscaping or open lots.
            In almond orchards ground squirrels can harvest an almond tree overnight. They are very active right now, chewing open the green, hard husk and taking the immature seed. Seeds right now are soft and sweet, not yet hardened. You will see lots of empty shells on the ground from these critters.
Empty almond husks at the bottom of the tree's canopy from ground squirrels
            Ground squirrels continue to feed on nuts throughout the season. When the husk splits open, they steal the nuts a lot faster and store them away somewhere. It is usually safer to harvest the nuts as soon as they split open and not leave them on the tree to dry.
Ground squirrel grape thievery
            I know that these little guys look cute but they can be real pests if they get out of control. They will also steal grapes right out of bunches. Bunches with stolen grapes look just like you think they might look, a bunch with grapes missing here and there on the outside of the bunch.
Antelope ground squirrel adding insult to injury
            Control is not easy nor is it any fun. In commercial orchards they frequently use poison bait to help control the population. There are other options such as trapping and relocation.
            Please be very careful when dealing with ground squirrels. It is rare but they can transmit the Plague from flea bites or bitten directly by the ground squirrel.
            Here is some very good information on ground squirrels from the University of California

Nectarine Fruit and Dried Droplets of Sap

Q. I have an Independence nectarine tree which I have been nurturing for two years. This is the first year I have had fruit! On the fruits I kept I am seeing something that looks like dried droplets of sap coming out of the skin. It is not sticky to the touch. Are you able to determine if I have some sort of blight with the fruit? Will I just need to take this plant out?

A. Your nectarine fruit has damage caused by Western Flower Thrips. This is a very common problem with nectarine fruit here in the valley and elsewhere. Once you see your fruit damaged by this insect, you will see it in future years as well. Be prepared to spray.
            Damage to the fruit starts before they are the size of a pea. The only control is to apply sprays to the fruit and leaves to protect the fruit from thrips damage. The most effective sprays are insecticides for organic production contain Spinosad in the list of ingredients. Follow the label precisely.
Readers nectarine fruit with dried sap due to thrips damage
            If you don't mind applying an effective conventional insecticide, then look for one containing synthetic pyrethrins, sometimes called pyrethroids. The label must say it is approved for tree fruits. Again, it is very important to read and follow the label for best results.
            These sprays must be applied to the fruit and leaves starting very early in the season when the fruit are still very, very small. Sprays must be repeated through the season for total protection. Chances are, you will still see some scarring of the fruit but it will be greatly improved.