Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
Hort Update for October 21, 2013
|1. Kentucky bluegrass rust||Orange powdery spores on lawn mower and shoes|
|2. Late fall seeding very risky||Dormant seeding is a better option|
|Sod cool season turfgrass up until a hard freeze|
|4. Final fertilization of year||Important application to time with last mowing of the year|
|Trees & Shrubs|
|5. Ash seed weevil||Tiny grub-like larvae found inside ash seeds|
|6. Over-mulching encourages critters||Deep mulch near tree base invites voles and mice|
|7. Rabbit and deer protection||Put protection method in place during late fall|
|8. Fall and winter watering||Fall watering critical, winter water under certain conditions|
|9. Preventing winter desiccation||Fall watering critical; antidesiccant products an option|
|10. Tender bulbs ||Dig and store before they’re allowed to freeze|
|11. Pruning climbing roses ||Decreasing size helps reduce winter breakage|
|12. Mulch application ||Freshen mulched areas to the proper depth|
|Fruits & Vegetables|
|13. Proper produce storage ||Proper storage ensures produce lasts and remains safe to eat|
|14. Fall soil amendment ||Applying compost or manure in the fall helps improve soil|
|15. Soil testing ||Fall testing helps with amendments before spring|
|16. Seed orders ||Create and place orders for best selections|
1. Kentucky bluegrass rust symptoms appear in late summer and fall. They include rust colored "powder" (fungal spores) on grass blades, shoes and lawn mowers. From a distance, heavily infected lawns may have a yellow-green cast. On close inspection of infected grass blades, yellow flecks and rust colored raised postules will be found. Rust disease is considered a cosmetic issue for most residential lawns. It typically develops on lawns with slow growth. Fall lawn care practices, including fertilization, proper irrigation and core aeration, along with cooler fall temperatures that promote growth will lead to rust disappearing. Fungicide controls are rarely recommended for home lawns.
Note for Sports Turf- If stem rust occurs on sports fields, the fungal spores can cause problems for allergy/asthma sufferers. Control of stem rust is recommended on sports turfs using a combination of turf management and timely fungicide applications.
2. Late fall seeding risky - Cool season turfgrasses like Kentucky bluegrass and turf-type tall fescue are best seeded by September 15. While seeding might still be done successfully after October 1 with significant inputs and precautions, poor establishment and/or winterkill should be expected. Winterkill of all turfgrass plants can be through desiccation in dry windy areas, crown hydration in poorly drained areas, and/or direct low-temperature kill with dramatic temperature drops to extreme cold in the fall or winter. This late in the season, it is recommended to wait and use dormant seeding.
3. Sodding is still viable option up until a hard freeze for cool season turfgrasses. For success, proper soil preparation is important prior to laying sod; then the sod and soil must be kept moist until the sod roots into the soil, which may require watering all winter if on an exposed, windy site. Roots will continue to grow until soil temperatures drop below 40 degrees Fahrenheit as long as moisture is available. Sodding can also be done throughout the winter if sod is available, but some type of irrigation will be needed to keep crowns hydrated if on an exposed site or during an open winter. Sodding is an excellent way to prevent soil erosion over the winter.
Establishing Lawns from Sod, University of Nebraska-Lincoln
4. Final cool season turfgrass fertilization of the year is typically late October or timed with the last mowing. Make an application at a slightly lower rate of 0.5 to 0.75 lbs N/1000 sq. ft. with a primarily soluble nitrogen (N) source. The closer to the last mowing, the lower the N rate and the more soluble the nitrogen should be.
Winterizer fertilizers available in retail outlets often have high potassium and maybe phosphorus; however there is no benefit from applying these unless soil tests indicate a deficiency. Potassium and phosphorus also tend to be the most expensive nutrients in the bag, so they can be minimized unless a soil test justifies the need for their use.
Tweaking Late Fall Fertilization, University of Nebraska-Lincoln
Adults are small, yellow-gold weevils active in late spring and early summer. Eggs are laid in developing ash seeds during summer and the larvae spend several weeks feeding within the seed. One or two larvae may be found in each seed, partially or completely consuming the seed. The larvae are legless grubs, similar in appearance to fly maggots; pale yellow with a darker head, and only about 1/10 inches in length when full grown. There is one generation produced per season.
Larvae exit the seeds during fall, moving into the soil where they pupate. They do not affect tree health and are not harmful to other plants in the landscape. Control is not warranted.
6. Overmulching leads to critter issues - A deep mulch layer at the base of trees can make a warm winter home for voles and mice who then feed on tree bark and wood; often girdling and severely damaging trees. To avoid this damage, only use a three inch deep layer of mulch and do not pile it up against the base of tree trunks.
7. Rabbit and deer protection methods include exclusion methods, i.e. hardware cloth. If these can feasibly be put into place and extended above the potential snow line, this is the best protection against wildlife. Various taste repellants, such as Thiram or Millers Hot Sauce, can be effective in reducing deer and rabbit damage as long as animals have other food sources to turn to. Scent repellants, such as bags of human hair or bar soaps on a rope, have been shown to be effective in some situations. Repellants wear or wash off and repeat applications are needed. Think twice about feeding wildlife as this can attract and increase wildlife populations in an area; eventually leading to an increase in damage.
8. Fall and winter watering - Fall watering of trees and shrubs is most beneficial, in the absence of rainfall, to preventing winter dessication injury. During fall, keep the soil just moist up until the soil begins to freeze.
The priority for watering is young plants first, those planted in the last year and especially those planted this past fall, and evergreens especially those growing in exposed locations and near the south sides of buildings. Winter watering can be beneficial, but should only be done under certain conditions.
When watering, the soil should not be frozen and air temperatures need to be above 40 degrees. Irrigation should take place early enough in the day for moisture to soak into the soil to avoid ice forming over or around plants overnight. Water just enough to moisten the soil six to eight inches deep.
Fall and Winter Watering, Colorado State University
9. Reducing winter desiccation - Adequate fall watering is most important for reducing the risk of winter dessication, or drying of evergreen landscape plants. For plants growing in exposed locations and near the south sides of buildings, and those that have had issues with winter drying in the past; timely applications of an antidesiccant, such as Wilt-pruf, can be helpful.
These products can dramatically reduce moisture loss from evergreen foliage. They coat needle surfaces with a lightweight polymer substance, which serves to prevent water from leaving the foliage. In general, they last about 5-6 weeks before the sun and wind render them ineffective.
Applications should be made about 6 weeks apart, beginning around Thanksgiving, to protect valuable trees throughout winter. Antidesiccants should be applied when air temperatures are above freezing so the liquid will dry on the leaf surface before it freezes, allowing for better residual effect.
One word of caution - be sure to clean out your sprayer after making an anti-desiccant application. This is a glue-like substance and will harden in the linings and clog sprayers. A simple soap and water solution flush will prevent damage to sprayer equipment.
10. Tender bulbs - As the weather continues to cool, it is important to dig and store tender bulbs such as gladiolus, cannas, etc. Once frost has killed the top growth in fall, especially in cannas, cut off the foliage and dig up the rhizomes. Brush soil off the rhizomes and store them at 45 to 50 degrees F. Do not allow the rhizomes to freeze.
Dahlia tubers must be dug each fall and stored in damp sawdust or peat at 60 degrees F. Divide the tuber clump in spring leaving a part of the true stem attached to the tuber.
11. Pruning climbing roses and winter protection - While April is usually when we think of pruning roses, a few pruning cuts on climbing roses can help them make it through the winter successfully. Of course any dead stems can be pruned out, but it can also help to cut back some of the overall mass of the stems to avoid winter injury. Never cut climbing roses until at least their third year, and wait until after foliage drop on shrub roses to reduce their height.
Protecting roses for winter - Wait until roses are dormant, once the leaves have dropped, the canes have turned a bit off color, and temperatures have consistently dropped into the 20's for several days. Mulching too early can lead to winter injury of roses. Once roses are dormant, cut them back if needed. Cover rose canes with wood chips, corn cobs, sawdust, pine needles, or pine cones. At least a bushel basket of mulch is needed for each rose bush. Keep mulch in place with a rose collar. Pre-made collars are available at hardware stores or garden centers. To make one, use a sturdy wire cage or find a large box. Open the box bottom, slide it over the rose bush, and fill it with wood chips. The canes of climbing roses need to be taken off of trellises. Older, broken and diseased canes should be removed at ground level. Dig a trench near the base of the canes and bend the remaining canes into the trench. Cover the canes with mulch. In spring, carefully dig the canes and reattach them to the trellis.
Fall Rose Care, University of Nebraska-Lincoln Extension
12. Properly applied mulch adds to the health and vigor of trees, shrubs, and perennials. The important words here are “properly applied.” Mulch that is improperly applied can be an obstacle to good plant health.
Properly applied mulch can:
- help maintain soil moisture
- provide needed nutrients
- improve soil aeration and limit soil compaction
- protect the plants from mechanical damage, such as a lawnmower
- reduce the growth of unwanted plant competition
- provide a better environment for beneficial microorganisms
Mulch mimics nature because the forest floor is generally covered with dead leaves, branches and other organic materials. As these materials break down they provide nutrients the tree picks up through the root system.
Many materials can be used for mulch, but organic mulch is best. Look for shredded wood or irregular-sized wood chips. Bark chips are lighter in weight, so can blow away more easily and they do not readily decompose to add organic matter to the soil. Pine needles make excellent mulch as they provide acidity to the soil and their structure provides a loose layer of material. However, do not use grass clippings as they will mat down, shedding water rather than letting it percolate through. If you have access to freshly chipped wood, let it compost for about three to six months before using it. And leaves raked in the fall can be used as well.
Inorganic materials such as river rock, lava rock and rubber mulch do not provide as many benefits as organic mulch.
Black plastic and woven or porous landscape fabrics, which are frequently placed below mulch, can severely limit oxygen and water infiltration into the soil. Rock material heats up the soil and surrounding plant tissues, leading to stress in the plant. The use of such materials is not recommended.
When applying mulch, aim for a depth of 3 inches. Thicker layers may attract hibernating rodents and other unwanted pests, especially in winter. In addition, mulch that is too thick restricts air and water movement into the soil, and causes poor rooting.
Mulching tender plants and fall planted or transplanted plants for winter is important in Nebraska; however, it is just as important not to apply winter mulch too soon. In most cases, wait until the soil freezes or temperatures begin to consistently drop into the 20 degree F. range at night.
13. Storing fresh fruits and vegetables properly is very important. Safe storage can keep you from getting sick from a food borne illness. Fresh fruits and vegetables should be stored unwashed. However, fruits and vegetables that are very dirty after harvest can be rinsed and dried well before storing.
14. Fall soil amendment, by incorporating compost or manure, is a good way to improve garden soils. The addition of organic matter improves drainage in clay soils and the water holding capacity of sandy soils. It adds essential nutrients and increases beneficial microorganisms.
However from a safety standpoint, manure must be handled and applied correctly. Only apply manures that have been aged for at least six months to minimize the risk of burning plants with excess ammonia. It is best to use manures that have been properly composted (to a temperature of at least 140 F.) to kill harmful E. coli bacteria that may be present in raw manure. Proper composting is critical for using manure in food gardens to avoid potential human illness. Manures from carnivorous animals should never be used. Additionally, if soils have high levels of salts, feed lot manure should be avoided as they will add to the problem.
Incorporating Manure in the Vegetable Garden, Colorado State University
15. Soil Testing - If you’re concerned about the soil quality in your landscape, whether it’s your turfgrass, ornamentals or vegetable garden, a soil test can give you basic information to help you start improving it. Soil testing isn’t very expensive or difficult to do and can be done anytime the soil is not frozen. Fall is an excellent time of year for soil amending, because it allows time for the soil structure or chemistry to change before a new growing season begins.
Soil Testing and Amendments, UNL Extension
16. Seed Orders - After perusing garden catalogs, order seeds and plants early for best selection. Send off seed orders early to take advantage of seasonal discounts. Some companies offer bonus seeds of new varieties to early buyers. For suggestions of recommended vegetable cultivars to try in your garden take a look at the two publications below.