~Agricultural News~









Noxious Weeds of Idaho


   In accordance with Title 22, Chapter 24, Elmore County Weed Control is giving notice of weeds listed as “noxious” by the State of Idaho.

•        Black Henbane*                     

•        Bohemian Knotweed

•        Brazilian Elodea

•        Buffalobur

•        Canada Thistle*

•        Common Crupina

•        Common Reed Phragmites

•        Common/European Frogbit

•        Curlyleaf Pondweed

•        Dalmatian Toadflax*

•        Diffuse Knapweed*

•        Dyer's Woad

•        Eurasian Watermilfoil

•        Fanwort

•        Feathered Mosquitofern

•        Field Bindweed*

•        Flowering Rush

•        Giant Salvina

•        Giant Hogweed

•        Giant knotweed

•        Hoary Alyssum*

•        Houndstongue*

•        Hydrilla 

•        Japanese knotweed

•        Johnsongrass

•        Jointed Goatgrass*

•        Leafy Spurge*

•        Matgrass

•        Meadow Knapweed

•        Mediterranean Sage

•        Milium

•        Musk Thistle

•        Orange Hawkweed*

•        Oxeye Daisy*

•        Parrotfeather Milfoil

•        Perennial Pepperweed*

•        Perennial Sowthistle

•        Poison Hemlock*

•        Policemans Helmet

•        Puncturevine*

•        Purple Loosestrife*

•        Rush Skeletonweed*

•        Russian Knapweed*

•        Saltcedar*

•        Scotch Broom

•        Scotch Thistle*

•        Small Bugloss

•        Spotted Knapweed*

•        Syrian Beancaper

•        Tansy Ragwort

•        Variable-Leaf Milfoil

•        Vipers Bugloss

•        Water Chestnut

•        White Bryony

•        Whitetop*

•        Yellow Devil Hawkweed

•        Yellow Flag Iris

•        Yellow Floating Heart

•        Yellow Hawkweed

•        Yellow Starthistle

•        Yellow Toadflax*

*Found in Elmore

   It shall be the duty and responsibility of all landowners to control noxious weeds on their land and property in accordance with this chapter and with rules promulgated by the Director.







   When spring blooms, the Elmore Extension office deals with numerous calls concerning a variety of horticulture issues. Mir M Seyedbagheri, Extension Educator, spends a large percentage of his day looking at soil, plant and insect samples; giving his expert advice and solutions. This publication is meant to inform the public of the most common questions Elmore County citizens ask. This is not meant to diagnose your particular issue. When dealing with plant and tree diseases, there are many symptoms that are similar.  Simple nutrient deficiencies can mimic fungal, viral or bacterial disease. It is usually best to bring a plant sample into the Extension office for specific diagnosis and treatment recommendations.



1.       For this desert-like area, what plants are best for landscaping?  Understanding the environment of SW Idaho helps everyone make better landscaping choices. In order to conserve water, lower costs and provide a low-maintenance, eye-pleasing landscape, it is highly recommended that you use water-efficient as well as native plants. The Extension office can provide a list of drought-resistant and native trees, ornamentals and grasses. The typical suburban lawn consumes an estimated 10,000 gallons of water above and beyond rainwater each year.

2.       What is xeriscaping? It is planning and designing a water-wise landscape.  In some cases, proper native plant selection can reduce the need to irrigate at all. However, there are many who want color all summer long. Xeriscaping involves wise design that utilizes both native plants with drought resistant flowers to minimize irrigation. A good plan includes soil testing, picking the right plants and turf, setting irrigation efficiently, using organic mulches and maintaining your new landscape design. With the right xeriscape design, you can cut your water usage up to 50% this summer. Imagine how much water we could conserve if at least 25% of the neighborhood followed your example.

3.       Does an organic solution work better? Organic methods do work if the method is carried out diligently. Nature’s cycle of growth and decay has served to keep forest and meadows thriving without the intervention of man-made fertilizers. In organic gardens, natural balances exist. The problems gardeners have are that they interrupt this natural cycle by harvesting and removing everything. Dead leaves and crop plant residue should be left behind to be re-used by the soil. To keep the natural processes that feed our plants, we must add organic materials in order to improve the soil foodweb within the soil community. Encouraging biological diversity in your own garden can minimize the need for artificial pest and disease control. When a gardener must intervene, the choices made are of high importance. In some cases, the use of chemicals is needed, however if you are a vigilant garden warrior, you can prevent most problems from ever occurring.

4.       Are there organic ways to control pest? Here are some Low-Tech Ways To Control Pests:

•        Plant resistant varieties.

•        Keep Gardens Clean! Many pests (including cuke beetles and asparagus beetles) seek protection in--and even spend winter inside--crop debris. Always pull out any badly infested plant you spot during the growing season.

•        Turn, Turn, Turn... Turning the soil with a tiller, garden fork, hoe or other implement can help destroy the soil dwelling stage of many pests.

•        Get Into The Hand-picking Habit! Get out in your garden every day and do a walk through, looking for trouble--and when you find it, just pinch the offending pest between thumb and forefinger.

•        Use Water As A Pesticide! A strong spray of water from a garden hose can be a surprisingly effective controller of small caterpillars, aphids, mites, scale, and the like. One recent study at Texas A&M University found that water sprays reduced spider mite and aphids by 70% to 90%.

•        Protect Your Seedlings. Simple barriers such as catch crops are very effective at protecting young seedlings from pests.  A catch crop is a fast-growing crop that is grown simultaneously with, or between successive plantings of a main crop.

•        Plant A Trap. Bugs prefer certain predictable foods. By planting a few sacrificial "trap" veggies, you can lure them away from the veggies, you want, and then either sacrifice that crop or nab them while they feast.

•        Mix Things Up. You can confuse pests by mixing up your garden. In diversified planting (where you have, say, a tomato, a flower, an herb, a few carrots, another tomato, some greens, etc., in a given row), pests can't easily gain a stronghold the way they can in big single crop plantings.

•        Mulch Pests Away. Mulches help control pests by repelling and/or confusing them.

•        Invite beneficial insects to move in. Get the good bugs to work for you. Leave the garden spiders alone and let them eat. You can purchase lady bugs and praying mantis at local nurseries.

5.       Iron Deficiency or Heat Stress? Check leaves. Are the veins green but the rest is yellowing? Treat for Iron Chlorosis with 10-10-10 liquid fertilizer with added micronutrients (zinc & iron)

6.       I have insects eating my plants leaves, what insecticide should I use?  Most insects can be killed by a general insecticide. Unfortunately, beneficial insects are also killed. First, we need to see what insect it is. If you are not sure, bring a sample to the Extension Office for a diagnosis. Remember whatever the solution, always give your plants ample water and fertilizer to keep them strong and able to recover. In the home garden, it is always best to practice good organic controls. You can make a fungicide spray of sulfur dust or baking soda to suppress fungus. You can use pepper spray or garlic spray as an insecticide to keep the bugs away. Using a compost tea regularly when watering your plants will also serve to keep insects away. If the pests are out of control then you may have to resort to chemicals. As always, when using any chemicals, look at the ingredients and follow all directions.

7.       What is the best soil for my plants? Healthy soil makes a healthy plant which will therefore be stronger and more resistant to disease. Most of the problems that gardeners experience can be attributed to poor unhealthy soil. Good soil is 1/3 top soil, 1/3 sand and 1/3 organic matter (good quality compost or manure).

8.       What is the best way to feed my plants? In gardens and yards, the best is foliar feeding or soil applied fertilizers.


9.       What is Compost Tea and can it be used for a fungicide?  Compost tea has long been used as a fertilizer but it has been documented that good quality compost tea may also help plants suppress fungal diseases.  However, it can also have high soluble salt that could damage your plants.

10.     How do you make Compost Tea?  To make your own, follow these directions:

•        Use a burlap or cheesecloth bag containing 1 gallon of manure- based compost.

•        Steep in a 5 gallon bucket of water.

•        Leave it in a warm place for 3 days.

•        Stir it well and several times through-out the day.

•        Remove the bag and put the liquid in a sprayer or a watering can.

•        Remove all leaves damaged by disease, then spray or sprinkle the tea over the plant.

•        Repeat every 3 to 4 days if the plants still shows symptoms.

   This spray is most effective when applied in the evening so plant leaves will remain moist for a few hours.

11.     Bacterial Wilt: The main symptom of this disease is severe wilting of the vines, followed by rapid death of the plant. The disease is caused by the bacterium Erwinia tracheiphila, and at first may only affect a few vines on a plant. However, as the disease progresses, more leaves wilt, and eventually the entire vine is affected. Bacterial wilt is most severe on cucumber and cantaloupe and less severe on squash, pumpkin and watermelon. There is no chemical solution. The bacteria are carried from plant to plant by striped or spotted cucumber beetles. The beetles spread the wilt bacterium by feeding on infected vines and then feeding on healthy plants. Bacterial wilt can be reduced in your garden if the beetles are kept under control at the first sign of activity.

12.     What is Fusarium, Verticillium Wilt  and Curly-top? The verticillium wilt is caused by the soil-borne fungi; most apt to appear in July and August with signs of wilting. Chronic symptoms include small, yellow foliage, leaf scorch (marginal browning) and slow growth. If not caught in time, Verticillium wilt will cause a sudden and total collapse of the plant. Fungicides will not cure infected plants. Since it is a soil fungi, you will probably not be able to save the plants and must buy resistant ones. Remove all infested plants and debris. When you buy plants from the nursery, look for resistant types that have on the label either FW or VW & Curly-top.


FAQs about TREES

13.     What is the best thing I can do to prevent disease or insect damage to my trees?

•        First, do a complete visual check of your trees and shrubs 3 times as year. Early spring, mid-summer and fall

•        Deep Root Feed: Your best defense is a healthy tree. Strong vigorous trees are less susceptible to disease or insect invasions.  After treating a tree for any disease, it is always recommended that you do a deep root feed to strengthen the tree. Use a good liquid fertilizer. In our area most trees prefer a fertilizer with a 2-2-1 ratio, such as 10-10-5 with chelated zinc & iron.

14.     How do I do a deep root feed?

•        Using a soil probe which can be borrowed from the Extension Office or use any tool that will make small “silver dollar” size holes in the ground. Place15-20 holes in the ground around the root. This can also be done with a shovel, by pushing soil off to one side however it is not as effective nor will it go as deep as the soil probe which typically penetrates 12 inches.

•        Purchase liquid fertilizer with N-P-K rations of 20-20-20 or 10-10-10 respectively. If the liquid fertilizer doesn’t contain zinc and iron, add chelated zinc and iron to the solution.

•        Pour 2 pints of fertilizer solution (including 5 ozs. of chelated zinc and iron) in five gallons of water. Mix thoroughly. Please always read the label instructions and follow completely.

•        Fill each of the holes with the solution until it drains. Repeat in all the holes until the solution is gone. For smaller trees, you can use Ό -½ of the indicated amount.

Note: if you are not able to get liquid fertilizer, you can substitute four cups of dry granular fertilizer with similar rations (20-20-20) and chelated or granulated zinc and iron. In this case, it may take longer for the fertilizer to move down to the root zone.

15.     What causes the leaves on my tree to be have dead spots? Anthracnose is a fungus disease reported quite often in Idaho.  It seems more common when there is a wet spring. Leaves get tan spots that develop purple rims. Leaves may also have necrotic (dead) veins and leaf margins, and large necrotic blotches. In some cases shot holes appear. Infections often progress down the petioles of blighted leaves into shoots, resulting in trunk cankers in trees.

16.     What is making my trees leaves turn brown and falling off ? (not autumn season) Could be several issues so it usually best to bring a sample for diagnosis.  One possibility is heat-drought-water stress.


•        Check leaves. Are the veins green but the rest is yellowing?

•        Treat for Iron Chlorosis

•        Deep Root Feed with 10-10-10 liquid fertilizer with added micronutrients and be sure it has chelated iron. If not, add it. 


17.     My evergreen tree is dropping needles: needles are spotted and dying. Needlecast (Rhizosphaera): starts on lower branches and works it’s way up.

•        Prune the lowest whorl of branches at first opportunity.

•        Clean out debris from in and around trees then remove and destroy debris.

•        Avoid planting in low-lying areas with poor air drainage.

•        Space plants for good air circulation.

•        Control weeds around the bases of trees.

•        Shear trees during dry weather.

18.     Trees have blight? How do I treat it?

Prune and dispose of diseased twigs and branches, rake up all fallen leaves and twigs and burn it. Disinfect all pruning tools with a mild solution of bleach and water with a few drops of dish soap. Dip the tool after each cut. Any open areas left from the cuttings should be lightly coated with the solution.Elemental Sulfur dust can be applied from the base of the trunk to the dripline as a general natural fungicide. Read & follow directions completely.

19.     My tree has red burnt flowers. Fire Blight? Fire blight gets its name from the burnt appearance of affected blossoms and twigs.  Flowers turn brown and wilt; twigs shrivel and blacken, the ends often curling. There is no cure for fire blight and the best way to deal with the infection is to remove infected stems and branches cutting no less than 8 inches up from the infected area.  Because the bacteria are so easily transmitted, care should be taken in disposing of infected plant material. Either burn or discard in the trash.  Do not leave infected material where the bacteria might be spread to surrounding bushes or trees.  Care should also be taken with tools which have come into contact with the bacteria.  Tools can be sterilized in an alcohol solution (three parts denatured alcohol to one part water).  Diluted household bleach can also be used (one part bleach to nine parts water) as long as the tools are wiped dry after disinfecting to prevent corrosion.

20.     My spruce has web-like areas and with speckled needles.

Spider mites-Treat with dormant oil or with miticide when mites are active in spring and fall. It is also effective to spray wash with high pressure water.

21.     Why does my trees have discolored stains on the trunk? Looking closer the tissue underneath is dead. There are many forms of tree cankers. It is always best to bring a sample to your local extension office for a definite diagnosis.

Canker symptoms include dying or dead branches, with wilted leaves among healthy leaves. Cankers develop on the bark and appear dark or discolored. Cankers infect trees that are weakened due to disease, borers or stress. Can be fungal or bacterial, enters at the wound-site. It is important to get trees healthy with deep root feed & fungicide.

22.     Why do my evergreen needles have “cottony” growths on them.

Cottony Scale: Spray with insecticide when the insects are active, usually in April-May and July-Aug.

23.     Why is my tree discolored and leaking slimy stuff?  It could be Slime Flux, a bacterial disease.  Yeast grows on the slime. Prevent stress on tree, deep root feed to strengthen and make healthy.

24.     I have branches on my trees where all the leaves are wilting & others are stunted. What could be causing this? There are other stress factors that can cause these symptoms. One prevalent disease is Verticillium Wilt. This is a soil-born pathogen that is very hard to control. You may have to eventual get rid of the tree and plant a resistant variety. However, many trees can recover.  The best step is to get the tree healthy with a deep root feed. Fungicides are not effective for control of this disease.

a)       Why is my tree acting like it is fall in summer? Leaves are getting brown patches and falling off.  One of the most common problems in our area is Anthracnose. This fungus infects large veined leaves more often, caused by fungus usually brought on by cold and wet spring.  Rake and destroy fallen leaves.  Avoid overhead irrigation and promote good air circulation. Disinfect all pruning tools with a mild solution of bleach and water with a few drops of dish soap. Dip the tool after each cut. Any open areas left from the cuttings should be lightly coated with the solution. Treat tree with fungicide. Follow with early spring fungicide. If you use a chemical garden fungicide, such as Ortho Daconil, Bonide garden & ornamental fungicide, or a general lawn and garden fungicide---please read all directions carefully and used as directed.

25.     There are brown spots on my tree leaves and some are completely brown and falling off the tree.  This is commonly known as Leafspot. Treat the same as  Anthracnose.

26.     What if I don’t want to use a chemical fungicide.  You may use other organic alternatives to chemicals such as:

•        Barriers: A light spray of vegetable oil or highly refined horticulture oil coats leaf structures and acts as a barrier to fungal diseases, especially rusts and mildew.

•        Plant products: Garlic can be used as a potent broad-spectrum insecticide and it has fungicidal properties when blended with water, strained and applied to the leaves. The same is true of compost tea*.

•        Baking Soda: Actually this may come closer to killing off fungus than most fungicide. It’s also nontoxic. Mix 2 teaspoons per gallon of water, adding a few drops of dish soap to help the solution stick to the plants.

•        Bonide - Tomato And Vegetable 3 In 1 or Lilly Miller - Cueva Copper Soap Most of these organic solutions have to be applied at least every 10 days during growing season.

   The UI Elmore County Extension office provides a wealth of horticulture information.

   If your lawn, trees, garden plants or ornamentals are exhibiting signs of disease or insect damage, simply cut a sample, place into a clean sealed bag and bring it to the office at 535 E. Jackson.

  The Extension Educator can identify the problem and give expert recommendations. You can also have your soil tested for nutrients and receive a detailed report along with recommendations for soil amendments. If you have questions, call the office at 208-587-2136 ext.509 or email us at elmore@uidaho.edu. Visit our website at:


   The University of Idaho does not discriminate in education or employment on the basis of human differences, as required by state and federal laws.





FAQS About Soil and Fertilizing


   Soil is a living system. Soil is defined as the upper few inches or feet of the earth’s crust. It furnishes mechanical support, food, water and air for growing plants. Active healthy soil contains humus (organic matter), clay, mites & nematodes, fungi & bacteria, plant roots, decaying organisms, air & water, and finally sand & silt. A good gardener understands the importance of active healthy soil. Robert Rodale, former editor of Organic Gardening magazine said, "Feeding a plant artificial fertilizers is basically the same as feeding a person intravenously." Plants, like us, can't survive on junk food, either. Rodale also emphasized what science has always confirmed: a successful garden begins with healthy soil, "Ninety percent of all garden failures are caused by poor soil," he said.

   The Elmore County Extension office receives over 100 calls monthly related to garden issues. At this time of year, we get a lot of questions regarding spring soil preparation. Here are the top 25 questions we encounter each year.

   1. How do I know what type of soil I have? How do I know if my soil is healthy or if I need to add something to make it right for planting? Visual symptoms can be used to identify problems, but ultimately a soil test is the best way for an accurate diagnosis. If you suspect salinity problems, the Extension Office can do a soil test. You can borrow a soil probe and get a lab soil bag.  Collect soil samples in various places from the top 6 to 12 inches of soil and place in a clean sterile bucket; mix it well. Then place a pound of soil in the bag and take it to your local extension office. You will receive a detailed soil analyses along with expert recommendations from the Extension Educator.

    2. What is the best type of soil? There are three types of soils, loam is the most favorable for plant growth.

 Loam Soils-Best

 • A mix of sand, silt, clay and organic matter

 • Loose and look rich

 • When squeezed in the hand, it forms a ball

 • Normally absorb and store moisture well

 Clay and Silt Soils-Good

 • Made of tiny particles

 • Feel slick and sticky when wet

 • Make “snakes” when rolled between your hands

 • Hold moisture well

 • Resist water infiltration

 • Are easily compacted

 • Water often puddles on their surface

Sandy Soils-Fair but needs help.

 • Contain large particles which are visible to the unaided eye

 • Are usually light in color

 • Sand feels gritty and will not form a ball when squeezed in your hand

 • Loose and drain easily


 3. What will a soil test tell me? Soil testing will give a report that typically evaluates macro nutrients (N-P-K), micronutrients (zinc-iron etc), pH and EC (electrical conductivity) as part of a routine analysis. If the pH is high (>8.5), sodium adsorption ratio (SAR) should also be calculated. The report will tell you the texture and cation exchange capacity, as well. A more in depth report will detect all the macro & micro nutrients, showing the ideal ratio compared to your ratio. Your Extension Educator can then use this report to give an accurate recommendation on what amendments your soil may need.

   4. How much water typically will my soil hold?

           TEXTURE                                                         CAPACITY (inches water per foot soil)  

  Coarse: coarse to loamy sand                                          0.5 - 1.0

  Light: loamy fine sand to fine sandy loam                      1.0 - 1.5

  Medium: very fine sandy loam to silt                              1.5 - 2.0

  Fine:  sandy clay loam to clay                                         2.0 - 2.5


   5. Why do we need to add iron in the soil?

·        Aids in energy transfer

·        Activator for enzymes that control respiration

·        Required for chlorophyll formation

   6. How do I get the soil ready for planting a new flower garden or vegetable garden? First you need to know what type of soil you have and the Ph level.

Generally, the normal preparation for the soil is to apply the following:

 • 2 cubic yard of good quality compost (salts <3 mmohS/cm & C:N ratio of 20-1)

 • Apply 20 lbs per 1,000 sq.ft. of elemental sulfur

 • Fertilizer (15-15-15) with added chelated zinc & iron.

 • Till this mixture into the soil to a depth of about 3-6 inches.

   7. What is fertilizer? A fertilizer is any substance that contains one or more recognized plant nutrients. It is made up of mineral salts containing nitrogen (N), phosphorus (P) and potassium (K) which when dissolved in water, will provide those 3 major nutrients. Fertilizers may be divided into two broad categories, natural and man-made. Natural fertilizers generally originate from unprocessed organism sources such as plants or animals. Man-made fertilizers can be organic (for example, urea) or inorganic (for example, superphosphate).

   8. How do I know what fertilizer to use? Soil pH should be considered when selecting the fertilizer.  Slow-release fertilizers are preferred, but similar results can be obtained using small amounts of soluble fertilizers applied frequently. Read and follow all label instructions and safety precautions

The analysis, or grade, of a fertilizer refers to the amount of nitrogen (N), phosphorus (P), and potassium (K) in the fertilizer. The analysis is always printed on the fertilizer label. A well balanced fertilizer of 15-15-15 (NPK) is recommended with added zinc & iron.

    9. What are organic fertilizers? These fertilizers are not man-made chemicals but made from organic matter. There are two types of organic fertilizers.

 • Plant: compost made from decomposed plants, vegetables and fruits to form a more stable soil like material. 

 • Animal: such as cow or chicken manures. Manure is an excellent fertilizer containing nitrogen, phosphorus, potassium and other nutrients. It also adds organic matter to the soil which may improve soil structure, aeration, soil moisture-holding capacity, and water infiltration. Poultry manure is typically higher in nitrogen.  Whatever manure you use, be sure that it is weed seed free and salt content is low.


   10. What is organic matter? Organic matter (OM) is a natural transformer. It is decomposing plant and animal tissue being transformed into new compounds which in turn supply nutrients to the plants. It acts like a sponge with the ability to hold 6 times its weight of water. Stable OM can hold on to nutrients like a magnet. In addition, OM holds pesticides which serve to keep it from entering our water supply. Adding organic matter will provide food for microorganisms, worms, insects, and other organisms. It degrades potential pollutants and helps fight disease. Supplemental OM will allow better root penetration, improves water infiltration, makes tillage easier and reduces erosion.

   11. Is using manure a safe means of incorporating organic matter in your soil?

Yes, if the manure is composted or sterilized as opposed to raw manure. Composted manure offers advantages over raw manure including macronutrients, weed control and disease control. It provides substantial quantities of the macronutrients nitrogen, phosphorus, and potassium.  Microorganisms in the compost pile holds nutrients which prevents leaching.  Raw manure can have weed seeds and will not be sterile. Another consideration is the salt content.

   12. How do I apply fertilizers? When using commercial fertilizer, always carefully read and follow all directions.

 • Gardens: incorporate into the soil along with topsoil and organic matter or you can band it two (2) inches to the side of the garden row.

 • Lawns: Fertilizer for lawns should be 3:1:2 ratio. Established lawns require 0.5 to 1.0 pound of N per 1,000 square feet per month of active growth. So divide that amount into thirds. Apply September, November and late May of early June.

 • Shrubs/trees: Spread fertilizer around the drip-line. However, the best treatment is a deep root feed. Mix liquid fertilizer, makes small holes around the drip-line and fill with solution. This will take it directly to the roots where it will then be taken up into the entire shrub or tree.

   13. Does my soil need anything else besides N-P-K fertilizer? Yes, good compost and good healthy soil needs secondary elements and micronutrients. There are 16 elements that are now considered essential.

   14. What are secondary elements & micronutrients?

       i. Secondary nutrients:        Ca, Mg, S

       ii. Micro nutrients:              (B), (Cu), (Fe), (Mn), (Mo), (Zn), (Cl)

   15. What is Compost Tea? This is a liquid made from steeping water with manure or compost. This can be bought commercially or you can make it yourself. Research shows that compost tea, long used as a fertilizer, can also help plants fight off fungal diseases such as powdery mildew and tomato late blight. Microorganisms in the compost apparently either grow more successfully than or actively attack the disease causing fungus.

   16. So you have a recipe for compost tea? Make the tea by steeping a burlap or cheesecloth bag containing 1 gallon of well -aged, manure- based compost in a 5 gallon bucket of water. Stir it well and leave it in a warm place for 3 days. Then remove the bag and put the liquid in a sprayer or a watering can. Remove all leaves damaged by disease, then spray or sprinkle the tea over the whole plant. Repeat every 3 to 4 days if the plants still shows symptoms. This spray is most effective when applied in the evening so plant leaves will remain moist for a few hours.


   17. What is Cation Exchange Capacity? In soil science, cation exchange capacity (CEC) is defined as the capacity of a soil for ion exchange of cations (positive charged elements) between the soil and the soil solution. CEC is used as a measure of fertility, nutrient retention capacity, and the capacity to protect groundwater from cation contamination.

   18. What are soil aggregates? Soil aggregates are ‘clumps’ of soil particles that are held together by moist clay, organic matter, bacteria and fungi. These particles fit together creating varying sizes of space which are needed for microbial, oxygen and water movement.

   19. How do I know what the salt content of my soil is? Visual symptoms of the plants can be used to identify these problems, but ultimately a soil test is the best way for an accurate diagnosis.

   20. How high can the salt be in my soil? The acceptable base saturation limit for sodium is <5%. Soil salinity is the salt content in the soil. Stalinization is a process that results from:

 • high levels of salt in the soils.

 • landscape features that allow salts to become mobile. (movement of water table)

 • climatic trends that favor accumulation.

 • human activities such as land clearing and aquaculture activities.

Salts can also be deposited via dust and precipitation. As the sodium predominates, soils can become sodic. Sodic soils tend to have very poor structure which limits or prevents water infiltration and drainage. The consequences of salinity are

 • detrimental effects on plant growth and yield

 • damage to infrastructure (roads, bricks, corrosion of pipes and cables)

 • reduction of water quality for users, sedimentation problems

 • soil erosion

   21. What is the importance of the Soil PH? It is a measure of the soil acidity or Soil alkalinity. An acid solution has a pH value less than 7. While a basic solution always has a pH larger than 7. The pH can affect the availability of nutrients in the soil. Many nutrient cations such as zinc (Zn2+), aluminium (Al3+), iron (Fe2+), copper (Cu2+), cobalt (Co2+), and manganese (Mn2+) are soluble and available for uptake by plants below pH 5.0, although their availability can be excessive and thus toxic in more acidic conditions. In more alkaline conditions they are less available, and symptoms of nutrient deficiency may result, including thin plant stems, yellowing (chlorosis) or mottling of leaves, and slow or stunted growth. Before altering the pH levels, you should have a pH soil test. Adding elemental sulfur will lower the pH.

   22. What is the PH range for our area? (SW Idaho) PH ranges from 7-8.4. Most of the crops function at the PH of 6.5-7.5.

   23. What is Humic acid? Humic acid are a family of organic molecules made up of very long carbon chains and numerous active radicals such as phenols and aeromatics. Humic substances are rich in carbons, which fuel the activities of beneficial soil microorganisms. Humic substances have been documented to interact in some manner with over 50 elements from the periodic table. Humic acids are now being used on hundreds of thousands of acres for enhancing soil physical, chemical and biological properties and fertilizer use efficiency. This has economically benefited the growers, the soil environment, and has strong implications for surface and ground water protection.

   24. What are benefits of adding Humic substances to the soil? It can hold 80-90% of it’s weight in moisture, therefore making your soil more drought-resistant. It reduces compaction, giving better root penetration and water movement.

   25. What types of materials do you use for composting? It has been done with a wide variety of substrates including yard waste, food waste, and manure.  Do not use: Metal, glass, rubber, domestic pet waste, meat/bones, fat-grease-butter-mayo, peanut butter, cheese or dairy products, fish products or any substance contaminated with pesticides or materials that attract.

    If you have further questions, need a soil test or a solution to a horticulture issue, please call us at 208-587-2136 ext 509 or email us at elmore@uidaho.edu or stop by the office at 535 E Jackson. The University of Idaho does not discriminate in education or employment on the basis of human differences, as required by state and federal laws.

Submitted to Hi-Lites April 2010 mydocs: 2010Activities/Publications/PopularPress/HiLites