Wednesday, June 30, 2010

Fertilizer needed for your sweet corn, squash, pumpkins, cucumbers and melons

Many gardens already have sweet corn with at least 8 leaves. If your sweet corn has this many leaves it needs to be fertilized. For every 250 feet of row, scatter ½ pound of Nitrogen along the side of the row, carefully rake it in and water to move the nitrogen into the root zone.

The sweet corn in the photo is yellow due to a lack of nitrogen fertilizer. Applying nitrogen will help correct that problem.

If your cucurbits (squash, pumpkin, cucumber & melon plants) are vining as is seen in the photo, you should fertilize with 0.1 pounds of nitrogen per 250 foot of row in the same manner as I’ve described with corn.

One-tenth of a pound of Nitrogen and even one-half pound of nitrogen seems like an awfully small amount and it is but these small amounts are necessary to keep these plants growing properly so they will produce the quantity and quality of vegetable you expect to harvest.

One-tenth of a pound of nitrogen does not mean one-tenth of a pound of fertilizer. No fertilizer is 100% nitrogen. Fertilizers, whether synthetically manufactured or organic, contain varying levels of nitrogen. If you use ammonium sulfate as your nitrogen source, it contains ~20% N. Therefore 5 pounds of ammonium sulfate equals 1 pound of nitrogen. If you use Corn Gluten (~10% N) as your nitrogen source it will take 10 pounds of corn gluten for every pound of Nitrogen.

Depending on what you are using for fertilizer, calculate the amount of fertilizer needed based on its nitrogen content and fertilize. For more specifics on how much Nitrogen your vegetables need, check out the fact sheets at and These fact sheets provide more information on fertilizing your vegetable garden and the organic products available.
The above photos also show a drip irrigation system used to water these vegetables and shades on the west and south sides of the cucurbits. Both of these methods of production increase yield and the quality of your vegetables.

Monday, June 28, 2010

Hollyhock Weevils (Apion longirostre) are Bad!

Adult hollyhock weevils are often neglected until they start to cause major damage to your hollyhocks. The adults eat tiny holes in the leaves. These holes can coalesce into larger holes as the leaf expands creating an unsightly plant.

The adults are no more than 1/8th inch in length and consequently seldom seen except by those who get their noses within an inch or so of the plant. . Even then the adults may not be seen as these tiny beetles notice changes in light and movement and either hide under the leaves or drop to the ground. This pest is easy to identify as it has an exceptionally long snout as you can see in the photo.

If your hollyhocks have holes in their leaves, the problem is the Hollyhock Weevil. Hand picking this pest off the plant is next to impossible as the adults drop to the ground when the plant is disturbed. You can take advantage of this by placing a sheet under the plant and shaking the stalk. The adults will drop onto the sheet making them easier to capture and crush. Picking off the developing seed heads removes the source of the adults as the larvae feed and develop in the seeds.

A product containing the active ingredient imidacloprid and applied as a soil drench will kill the adults and larval stages. A spray of a product such as permethrin or carbaryl is also very effective. The organic insecticide pyrethrum will also work. Sprays should be avoided in the heat of the day as leaf burn can occur. We have had problems with Pyrethrum burning leaves even when it is sprayed in the evening so treat a small portion of the plant and wait a day to see if any phytotoxicity occurs. Make your additional applications based on the result of your test treatment. Always check the label to ensure the product can be used on ornamental or flowers.

Is your spinach going to seed?

If your spinach is going to seed, i.e. bolting, it is time to pull it. When spinach starts to bolt, new leaves have an arrowhead shape and tend to become more bitter than usual. If you want a leafy vegetable crop for the summer try one that can tolerate the heat. These include Malabar spinach (Basella alba), Swiss Chard and New Zealand spinach. You will need to keep the soil moist and shaded in order to get a good stand. If the soil cakes or dries out, the germinating seed and emerging seedlings will die.

Leaf miners can be a problem with these crops but you can prevent infestations of this insect by covering the crop with insect barrier, a spun-bonded polyester fabric. I like to cover the row with this product as soon as I get the seeds in the ground. Cover the edges with soil but leave the fabric loose enough so these greens can push it up as the leaves develop. The fabric also helps retain soil moisture and shades the soil reducing heat buildup resulting in healthier plants. Mulch around the plants also helps improve plant health and production.

Thursday, June 24, 2010

Time to treat for Crown Borer aka Peach Tree Borer

The first male peach tree borer of the season was in our trap near our office on Orchard Mesa on Wednesday morning, June 23. Now that we know the males are out, the females will soon follow. The photo to the left is of the female peach tree borer moth.
Mating occurs as soon as the females emerge; egg laying starts the same day. The eggs typically hatch within 10 days of being laid. An insecticide needs to be applied prior to egg hatch to kill the emerging larvae before they can bore into tree. Once under the bark this insect is very difficult to control.

The larvae feed in the cambium and inner bark of the lower trunk and roots and will kill the infested tree or shrub if treatment is neglected. The typical symptom of an infestation of crown borers is the sudden collapse and death of the tree or shrub. This may appear to happen almost overnight.
Do not procrastinate about applying a treatment to the base of your trees. Drench the trunk up to 8 inches above the ground and soak the soil with an insecticide containing permethrin, carbaryl or other insecticide approved for use on fruit trees. Read the label to ensure the product can be used in that manner. This is a clear-wing moth thus insecticides consisting of imidacloprid will not work.
All trees and shrubs in the genus Prunus to include peach, nectarine, cherry, plum, almond and apricot, whether of the fruit-bearing type or not are susceptible to this insect and should be treated. Even Cistena plum and sand cherries are susceptible. Treatments need to begin the year the tree or shrub is planted and continue throughout its life.
For more information on this pest check out the information at

Tuesday, June 22, 2010

Don't delay treatments for squash bug

Squash bugs are already active in the Grand Valley. If you wait until you find eggs on the underside of the leaves of your summer and winter squash and pumpkin plants, the adults will have already been feeding on these plants. When squash bugs feed at this time of year they can delay plant growth and even kill seedlings and young plants.

The insecticides carbaryl and permethrin provide excellent control. Diatomaceous earth and pyrethrins are also effective. These materials are best applied to the underside of the leaves and around the base of the plant. To ensure the insecticide sticks mist the plants prior to apply the insecticide. Follow label directions on timing, pre-harvest interval and application rate. The label is the law and needs to be followed.

You can find more information on squash bugs at

Hot soil needs to be shaded

At 5 this evening I used a digital thermometer to determine the soil temperature 1 ½ inches below the soil surface in three different spots at the ‘Grand Junction Community Garden at the Library’. The results were as follows:

Soil shaded with CSFS shades – 83.3 o F.

Soil in a walk way covered by bark mulch - 84.2 o F.

Bare soil neither shaded nor covered with mulch – 104.6 o F.

Most roots shut down when soil temperatures approach 90 o F. Roots will not take up water or nutrients at high temperatures.

The morale of the story is to shade the soil to keep your plants' roots happy. The use of insect barrier (spun-bonded polyester available from some local nurseries) and the CSFS (970 248-7325) shades help keep the soil cool. Homemade shades and even window shades can be used to shade plants and soil. The use of a bark mulch, shredded bark or wood chips can be used to protect the soil from the heat of the sun.

Avoid hay or straw as these often have seeds increasing weed problems.

With small plants a fine layer of mulch will need to be added to as the season progresses and the plants develop. Don't suffocate the new plants with too much mulch. More mulch will need to be added as the months go by. The mulch can be tilled in at the end of the growing season.

When you apply mulch keep it an inch or two away from the base of the plant. This will help avoid stem rot. Apply the mulch when the soil is cool not in the heat of the day.

Sunday, June 20, 2010

vegetables need fertilizer now!

Even if a soil test of your garden showed an adequate amount of Nitrogen (N) to start the season, more nitrogen is often necessary at this time of year to ensure your garden produces abundantly.

When sweet corn has 8 to 10 leaves, fertilize.

When tomatoes are the size of golf balls, fertilize; for cherry tomatoes fertilize when the fruit are the size of a dime.

When your squash, cukes and other vine crops begin to vine, fertilize. If you have bush varieties of these vegetables, be sure to fertilize them when your vining crops start to vine.

Avoid the tendency to over fertilize.

For the specifics check out

Remember: Always apply fertilizer to moist soil.

Friday, June 18, 2010

Brown spots on pear leaves

The brown spots on pear leaves are seldom the result of a fungus but due to an eight-legged eriophyid mite called the pearleaf blister mite. This mite is about one-quarter the size of a spider mite but you can see them with a 14 to 20X hand lens.

This pest feeds between the upper and lower tissue of the leaf. The spots are slightly raised and each has a tiny hole somewhere near its center. The mites enter these holes and feed on the soft tissue inside.

The photo shows several leaf blisters. The one in the upper left has an eriophyid mite emerging from a hole.

This mite also damages the fruit causing oval russet spots. Management includes the use of dormant or delayed dormant oil in the spring. The mite overwinters at the base of buds or under the outer bud scales. Apply the oil until it runs off the tree.

At this time of year, unless you are a commercial orchardist, I would suggest an insecticidal soap or a vigorous washing down of the tree with a hose. Make sure the water you use is cool or cold and not hot! Weekly washing would not hurt. Avoid the use of insecticidal soap and other insecticides during the heat of the day. Late evening or early morning treatments are more effective and cause less burning on foliage.

Fertilizing container plants

If the bottom leaves of the vegetables and flowers in your containers are turning yellow or light green this is most often due to a deficiency of nitrogen. This is more of a problem in containers due to the flushing of nitrogen out of the soil when watering. This is also more of a problem in raised beds than in regular gardens.
Nitrogen, unlike iron, is mobile within the plant. As new leaves are formed, nitrogen will be pulled from the lower leaves to the new leaves. Thus the lower leaves lose their green color resulting in chlorotic leaves.

Chlorotic leaves on tomato, pepper, eggplant and other members of the potato family (Solanaceous plants) are more susceptible to early blight caused by the fungus Alternaria solani. Applying fertilizer containing nitrogen on a regular basis during the growing season will help prevent chlorosis as well as early blight.

It is critical that you avoid excess applications of nitrogen as this results in more vines and less flowers and fruit. Any liquid fertilizer containing nitrogen will work to correct chlorosis. Instead of fertilizing at full strength, apply the fertilizer at half rate but twice as often as recommended. I do not suggest the use of fertilizer spikes in containers. Always make sure the soil is moist before applying the fertilizer.

Tuesday, June 15, 2010

Grape Powdery Mildew sprays needed

"The wet conditions over the weekend have most certainly resulted in a primary infection of grape powdery mildew. Fungicides should be applied ... Good spray coverage is important, including on new shoots being trained up from the ground. Do NOT skip powdery mildew (or other pest/disease) control even in situations where most or all vines have been killed to the ground - excessive powdery mildew infection will reduce winter hardiness of your shoots/vines, increasing the risk of future cold injury." Info from Dr Horst Caspari,State Viticulturist, Colorado State University

See for more information on this disease and fungicides you can use to manage this fungal disease.

Saturday, June 12, 2010

Fruit Tree insect Spray Needs

Mesa County:

Apple and Pear - The Codling moth is the insect in this area that causes wormy fruit. Thankfully we do not have the biostrain of apple maggot that cause so much trouble back east and in other parts of the nation. The first spray for the codling moth should have been applied within 10 days of full bloom. The second generation codling moth flight is expected on June 19 and an insecticide needs to be applied by that time.

The Peach Twig Borer causes damage to the fruit of peach, plum and apricot and causes new shoots on these trees to wilt and die. The first spray for this insect should be applied between June 10-15.

Western Cherry Fruit Fly: Based on the available information from Fruitvale and Redlands, it is time for the cover spray for this insect, especially in those areas.

Delta County:

Rogers Mesa
Apple and Pear - The second generation of the codling moth is expected on July 2-3. A spray should be applied by that time.

Peach, Plum and Apricot – The Peach Twig Borer spray should be applied between June 17-21.

Peach, Plum and Apricot – The spray for the Peach Twig Borer should be applied between June 19-24.

For further information on insects and disease of stone fruit tree check out our publication at .

Wednesday, June 9, 2010

Protecting your vegetables and flowers from drying winds and the hot sun

The heat and winds we have been experiencing has caused many of our newly planted vegetables and flowers to wilt. Due to the lack of roots on these new plants wilt no matter how much water you provide the plants . When our vegetables and flowers are stressed in this manner early in the season they will not produce the fruit or flowers they should for the remainder of the season. Providing shade to prevent this stress is strongly recommended.
Just about anything that cuts the wind and shades the plant will work. Old wood shingles pushed into the soil on the south and west side but several inches away from the plant works well. If you have constructed a trellis for your plants consider draping cheese cloth or a light shade cloth over the trellis and plants. Even old sheets can be used to cut the wind and cast a shadow on the plant.

Several weeks ago my grandson Soren set a cabbage plant out in his garden. As soon as the days got hot the plant wilted even though the plant was properly watered. The wilting was corrected when it was covered with a thin layer of spun-bonded polyester. This material allows sufficient light to get through to the plant while reducing the plant’s temperature. The material used is commonly sold as an insect barrier so it also solved the problems of caterpillars. If cabbage butterflies can’t land on the plant they can’t lay eggs on the plant.

In addition to the polyester fabric, I like to use the small shades available from the Colorado State Forest Service (CSFS). These shades are designed to protect tree and shrub seedlings but work just as well on other plants. I place these on the south and west side of tomatoes, peppers and even flowers. I use three (or even more) of these shades around each new transplant. Keep them far enough away from the plants so they don’t trap heat but still provide shade. I’m not sure the CSFS has any available at this time but if you are interested you might want to give them a call at their Grand Junction office at 970 248-7325. You can always make your own from wire and shade fabric.
Some of the gardeners at the Grand Junction Community Garden at the Library (5th and Chipeta) are cutting brush and pushing this into the soil to shade their plants.
Another technique that helps reduces stress on these new plants is to cover the soil around the plants with an inch or two of a bark or wood chip mulch. Do this early in the morning when the soil is cool. A layer of mulch when soil is cool will help keep the soil cool. If you apply mulch later in the day when the soil is warm you will trap in the heat of the soil. Roots are more capable of absorbing moisture and nutrients when the soil is cool. When the soil gets too hot, roots shut down and will no longer absorb water or nutrients even when the supply is plentiful.
Keep the mulch an inch or two away from the stem of the plant. You do not want to create an environment where disease and insect pests can attach the stem.
Avoid the tendency to water the plants whenever they start to wilt. Check the soil and if it seems there is sufficient soil moisture, the problem with water uptake may be due to a lack of adequate shade and a soil that is too warm for the plant’s roots. Give shading a chance.

Monday, June 7, 2010

Ute Pow Wow Saturday, June 12 2010

Ute Pow Wow - Saturday, June 12, 2010
At the Ute Learning Garden – CSU Extension Office – Mesa County Fairgrounds
Members of the Ute Indian Nations will perform at the Mesa County Fairgrounds on Saturday, June 12. Everyone is welcome to join the dances and learn about the Ute Indians.
10:30 is the Grand Entry when flags and staffs of the visiting Northern Ute and Ute Mountain Ute Indian tribes will be carried into the site by members of these Tribes.
Clifford Duncan, Ute Elder and Spiritual Leader will give a blessing in the Ute language and in English.

11:00 performances by Ute Indian dancers, singers and drummers will take place. The drum group is called Chapeta Lake singers. Visitors are welcome to join the dancers.
11:30 – 12 or there abouts - John Winn, local musician and composer – ‘This Lovely Planet’ - original song, words and music by John Winn
Tours begin at 9 a.m. and will be given every hour until 4 p.m. visitors will be escorted on tours of the gardens. They will see and receive an explanation of the traditional cooking hearths, the ‘Three Sisters’ garden, wickiups and teepee. Tour guides will discuss the history of the Ute Indians when they made Western Colorado their home. Visits to the various life zones from the low desert though the pinon-juniper zone to the ponderosa pine life zone will include explanations on how to identify the plants in each life zone and how they were used by the Ute Indians.

Native arts and crafts will be available. Two water colors by Ute Indian Artist Kessley LaRose will be available by silent auction. The winner of the silent auction will be identified at 4:00 p.m. at the Mini – Pow Wow. There is no need to be present.
The entry fee to the Learning Garden is $3 per person or $5 per family.

The above painting by Ute Indian artist Kessley LaRose will be sold at a silent auction at the mini PowWow at the Ute Learning Garden, June 12.

Tuesday, June 1, 2010

Tips for Asparagus Lovers

The asparagus I ordered a couple months ago finally arrived this past Saturday. I was wondering if my order had been lost so was surprised when the package finally arrived. Many mail order nurseries ship to Colorado based on Denver’s last spring frost, even when Grand Junction’s average last spring frost is a couple weeks earlier than Denver’s. If my order had been shipped earlier I would have had it planted and it would have been up just in time to be damaged by our last frost. Thankfully my order was shipped based on Denver’s weather.

I had grown Jersey Knight and Jersey Giant asparagus previously but decided to try Jersey Supreme this time. Jersey Supreme is supposed to able to produce one year sooner than most other asparagus. It is all male and capable of producing 10 pounds of asparagus per plant after the second year.

Purple Passion was the other cultivar I had ordered. This asparagus produces purple spears that are thicker but shorter than Jersey Supreme. Unlike Jersey Supreme but like most other asparagus cultivars Purple Passion can be harvested only sparingly the second year and then for 6 to 8 weeks starting the third year. Purple Passion is also called Viola and is said to be sweeter than other asparagus cultivars. Sadly Viola consists of both male and female plants.

Asparagus beds should last for 25 years or longer but often get crowded out by volunteer asparagus arising from seed dropped by female plants. When the selected variety is male this is not a problem.

I decided to plant Jersey Supreme in two rows four feet apart with eighteen inches between plants in the row. I dug a trench six inches deep and eight inches wide. This allowed me to spread out the roots evenly around the crowns with the buds up. I set the crown in the trench and then soaked the crown and trench and covered the plants with two inches of soil. As the spears grow I’ll continue to fill in the trench with more soil. While I could have filled the trench instead of doing this piecemeal, I like to see what is happening with the plant and decided to follow the older true and tested procedure of filling the trench in gradually.

Ohio State University reports that no matter how deep asparagus crowns were planted they always “floated” to a depth of 4.5 inches from the soil surface. The ultimate depth would vary depending on the soil type with crowns in a heavy (clay) soil being closer to the surface than crowns in a light (sandy) soil.

I prefer to put seeds and crowns in wet soil and then cover with dry soil. Covering with dry soil prevents the caking of the soil surface that happens when you water after you plant. I’ll also have less weed interference due to the layer of dry soil. After the crowns start growth I’ll check the soil moisture and water as needed.

The four foot spacing between rows permits access even when the crowns spread out and start to fill the area between the rows. The area between the rows appeared to be a waste of space. Since I had a package of mixed greens I watered the soil between the asparagus, scattered the package of seed and then lightly cover the seed with dry soil. The five varieties of lettuce, arugula, spinach, Swiss chard and other greens will be a great addition to our salads.

Purple Passion can be planted as close as 6 to 8 inches apart. The area I had available for this asparagus cultivar is a raised bed about five feet by five feet and next to my raspberry patch. Since I can get on three sides of this area it made sense to plant these crowns at the 18 inch spacing. I wanted to give these plants the best chance possible and this spacing seemed appropriate for the space available. I was able to plant six Purple Passion crowns in this area. The other 14 crowns were planted at the Mesa County Arboretum. These should create a very nice feathery screen at the back of the gardens and help cover up the chain link fence separating the Arboretum from the BMX track.

Many fact sheets recommend the addition of phosphorus. I did not add any phosphorus. A soil test showed there was already adequate phosphorus in the soil. Adding more would cause problems with other nutrients and mycorrhizal-forming fungi.

To ensure I created the best soil conditions possible for the asparagus, copious amounts of Mesa Magic was worked in two shovels deep. This compost will provide adequate nitrogen to give the asparagus a good start. Additional nitrogen will need to be added during the growing season to ensure the asparagus does its best. At the end of June I will fertilize the asparagus bed with a nitrogen fertilizer at the rate of 0.10 pounds of nitrogen per 100 foot of row. I’ll be using ammonium sulfate, a fertilizer with a nitrogen content of 20%. Thus I will be applying ½ pound of this fertilizer per 100 foot of row. If I was going to use an organic fertilizer I’d check out my list of organic fertilizers to determine their Nitrogen content and calculate the amount of the chosen fertilizer accordingly. This fact sheet is just one of many you can find in the vegetable pages at

Drip Irrigation as a way to water your garden

The drying winds we have been experiencing have been sucking water from plants and soil. Screens used to divert the wind and protect young plants from blowing sand and debris also help reduce this moisture loss.I get my screens from the Colorado State Forest Service office. You can reach them at 248-7325.

A layer of mulch placed around the plant also helps maintain soil moisture. If you live in an area where the soil is still cold, a layer of mulch is not recommended at this time as it prevents the soil from warming, delays emergence and can increase potential for root rot problems. Be sure the mulch is not placed against the stem of the plant as this can increase stem disease problems.

Take care to ensure newly planted tomatoes, peppers, eggplants and other plants have adequate soil moisture. Until you are sure the frost season is over you should keep an eye on the weather and provide protection as necessary for these warm-season vegetable crops. Walls O’ Water or other season extenders should be considered.

Drip irrigation is one way to provide moisture to your garden. Some gardeners lay leaky hose or sprinkler hose along their rows of vegetables and flowers and in their shrub beds. Some use drip tube (aka dripper line and drip hose) or drip tape while others use PVC pipe through which they have drilled small holes Any of these techniques work as a way to water the vegetables, flowers and shrubs.

The effectiveness of the drip irrigation system depends on the cleanliness of the water, the rate the water is applied, the spacing of the emitters and the distance between the lines of drip tube.
Sprinkler hose, soaker hose or leaky pipe tend to plug even when using domestic water due to the lime that precipitates outof the water and fills the emitters and weep holes. You can avoid this problem by occasionally running acid through the system, but since acid can burn holes through clothing and skin this is not something I recommend. The use of drip tape or drip tube are better options.

Drip tape is made from thin plastic and thus is not as durable as thicker-wall dripper line. Drip tape requires a pressure regulator of no more than 15 psi (pounds per square inch) for the 15 mil tape. Thinner tape requires a lower pressure. Higher pressures blows the drip tape apart. More detailed guidance on the use of drip tape can be found at .

Pressure regulators used with drip tube range from 20 psi to as high as 45 psi. With the psi as high as 100 at the pump or faucet, the pressure needs to be significantly reduced to use with drip tape and drip tube. You cannot reduce the pressure by turning down the flow at the faucet.Drip systems are not recommended with irrigation water unless you have very good filtration. You should consider using a filter even when the drip system is attached to domestic water. A 200 mesh filter is needed for drip tape and the ¼ inch drip tube. 150 mesh filtration is adequate for the larger 17 mm drip tube.

The drip tube selected should be based on the infiltration rate of the soil in your garden. The infiltration rate is a measure of how quickly water moves into the soil. Our silty clay loam soils have an infiltration rate of about 0.2 inches of water per hour. When water is applied faster than the infiltration rate, water pools or puddles. This causes soil particles to separate and a crust of silt and clay to cover the soil surface.

This is the same thing that happens when we have a heavy rain. A crust forms on the surface of the bare soil. This crust prevents water infiltration and forms a barrier to emerging seedlings. Applying water at the proper rate relative to the infiltration rate of the soil avoids the formation of this crust. Once a crust forms the soil needs to be raked or broken up to permit water to again enter the soil and for seedlings to emerge. Mulch helps reduce soil crusting but does not increase water infiltration.

Drip tube is available with different application (precipitation) rates. Drip tube with emitters spaced every 18 inches and rated at 0.4 gallons per hour applies water at a rate between 0.21 and .29 inches per hour. This is the proper application rate for our soil. Drip tube rated at 0.6 gallons per hour applies water at a rate of between 0.56 to 0.96 inches per hour. The ¼ inch drip tube is rated at 0.9 gallons per hour and applies water much too fast for our soil. Unless you have a very well drained soil, the 0.6 and ¼ inch drip tube is not what you should use. Lines of the 0.4 gallon per hour drip tube with emitters spaced at 18 inches should be spaced between 18 to 24 inches apart.

Irrigation companies seldom carry the 0.4 gallon per hour drip tube yet this is the one you should consider. They can order this for you. Be sure the emitters in the drip tube are eighteen-inch apart.