Video of the Week:
Self-Watering Planter Saves Time
Starting Tomatoes Early
Root Growth: Tomatoes need a soil temperature of at least 55 degrees to do well. Plastic mulch is most commonly used to warm the soil. Several days may be needed to raise the soil temperature. Check the soil temperature 2.5 inches deep in the soil at about 11:00 a.m. If that is not possible, check the temperature before leaving for work and again when your return and use the average of the two. You may wish to lay a drip irrigation line before installing the plastic to make watering more convenient. See accompanying article on laying plastic mulch.
Air Temperature: Plants must be protected from frost. Hot caps or water teepees are placed over the young plants to provide protection as well as a higher average temperature to encourage growth. Eventually the plants will outgrow the cover and start to develop flowers. But if the temperature goes below 55 degrees at night, tomato flowers may not set. The plant is not hurt, but the blossom will not set fruit or, if it does set fruit, the fruit is often misshapen.
How early can you transplant? Start with a date about 2 weeks earlier than normal. (Ward Upham)
Herbicides for Home Vegetable Gardens
The preemergence herbicide is trifluralin. Preemergence herbicides kill weed seeds as they germinate. They usually have no effect on weeds that have emerged. Therefore, they must be put on either before weeds come up in the spring or after weeds have been physically removed. The preemergence herbicide trifluralin is sold under the trade names of Treflan, Preen, Miracle-Gro Garden Weed Preventer, Gordon's Garden Weed Preventer Granules and Monterey Vegetable and Ornamental Weeder.
The postemergence herbicide is sethoxydim. This product only kills grasses; broadleaves are not affected. It can be sprayed directly over the top of many vegetables. Sethoxydim is sold as Poast, Monterey Grass Getter, and Hi-Yield Grass Killer. A second postemergence herbicide called fluazifop-p-butyl is labeled for commercial growers as Fusilade, but I haven't found vegetables listed on the homeowner labels, “Over the Top Grass Killer” and “Grass-No-More.” Also, the other homeowner products mentioned above often do not have as many vegetables on the label as the commercial products. Even among the homeowner products with the same active ingredient, there may be slight differences among labels. Check product labels to be sure the crop is listed. Here is a list of herbicides and the crops for which they are labeled. Many of these crops have application restrictions. For example, trifluralin can be used on asparagus, but must be applied before spears emerge. (Ward Upham)
Vegetable Treflan Poast
Asparagus X X
Beans X X
Broccoli X X
Cabbage X X
Carrot X --
Cauliflower X X
Corn, Sweet -- --
Cucumber X X
Eggplant -- X
Lettuce -- X
Greens X --
Muskmelon X X
Okra X --
Onion -- X
Peas X X
Pepper X X
Potato X X
Pumpkin -- X
Spinach -- X
Squash -- X
Sweetpotato -- --
Tomato X X
Turnip X --
Watermelon X X
Proper Timing for Crabgrass Preventers
For most of Kansas, crabgrass typically begins to germinate around May 1 or a little later. April 15 is a good target date for applying preventer because it gives active ingredients time to evenly disperse in the soil before crabgrass germination starts. The April 15 target works well for most of the state, but for southeast Kansas April 1 is more appropriate, and for northwest Kansas May 1 is best. Additionally, weather varies from one spring to the next, and with it the timing of crabgrass germination. It is often better to base timing on the bloom of ornamental plants. The Eastern Redbud tree is a good choice for this purpose. When the trees in your area approach full bloom, apply crabgrass preventer. A follow-up application will be needed about 8 weeks later unless you are using Dimension or Barricade. Products that do require a follow-up application include pendimethalin (Scotts Halts) and Team (Hi-Yield Crabgrass Control). Dimension and Barricade are the only two products that give season-long control of crabgrass from a single application. In fact, they can be applied much earlier than April 15 and still have sufficient residual strength to last the season. Barricade can even be applied in the fall for crabgrass control the next season.
Dimension can be applied as early as March 1. Because of the added flexibility in timing, these products are favorites of lawn care companies who have many customers to service in the spring. Though Dimension cannot be applied as early as Barricade, it is the herbicide of choice if it must be applied later than recommended. It is the exception to the rule that preemergence herbicides do not kill existing weeds. Dimension can kill crabgrass as long as it is young (two- to three-leaf stage). Dimension is also the best choice if treating a lawn that was planted late last fall. Normally a preemergence herbicide is not recommended unless the lawn has been mowed two to four times. But Dimension is kind to young tall fescue, perennial ryegrass, and Kentucky bluegrass seedlings and some formulations can be applied as early as two weeks after the first sign of germination. However, read the label of the specific product you wish to use to insure that this use is allowed. Lawns established in the fall can be safely treated with Dimension the following spring even if they have not been mowed. Note that products containing Dimension and Barricade may use the common name rather than the trade name. The common chemical name for Dimension is dithiopyr and for Barricade is prodiamine. Remember, when using any pesticide, read the label and follow instructions carefully.
We recommend crabgrass preventers be applied before fertilizer so that the grass isn’t Encouraged to put on too much growth too early. However, it may be difficult to find products that contain preemergents without fertilizer. Those that don’t contain fertilizer are listed below. I didn’t find any products containing Barricade that did not also have a fertilizer. If anyone knows of other products that should be listed, let us know and we will publish them in a later newsletter.
- Scotts Halts
Team (Benefin + Trifluralin)
- Hi-Yield Crabgrass Control
- Hi-Yield Turf & Ornamental Weed and Grass Stopper
- Bonide Crabgrass & Weed Preventer
- Green Light Crabgrass Preventer
How Low Should You Go?
Crabgrass seed must have light to germinate, and a high mowing height will shade the soil. Also, root depth and mowing height are related on upright growing grasses such as tall fescue and Kentucky bluegrass — the higher the height of cut, the deeper the root system. A deeper root system means a more drought-resistant turf.
So, how low should you go on the first cutting? On tall fescue and Kentucky bluegrass, you can mow as low as 1 to 1½ inches. Be careful you don't go so low that you scalp the turf. Normal mowing height for Kentucky bluegrass is 2 to 3 inches and for tall fescue is 3 to 3½ inches. (Ward Upham)
Brown Coloration on Junipers
Laying Plastic Mulch
1. Fertilize according to soil test. You won't be able to add fertilizer after the plastic is down.
2. Work the soil so that the bed can be easily shaped.
3. Use a garden hoe to form a trench along all edges of the plastic. The soil should be pulled to the outside of the bed. The trench should be formed six inches in from the edge of the plastic and extend along both sides and both ends. The trench should be deep and wide enough to bury six inches of plastic.
4. Lay trickle irrigation tube down the center of the bed. This isn't absolutely necessary but it makes it much easier to water. Overhead watering will hit the plastic and roll off.
5. Lay the plastic down and cover the edges with soil. You may need to slit the edge of the plastic where the trickle irrigation tube enters the end of the bed.
6. Plant when the soil temperature reaches the correct temperature for the crop (55 degrees for tomatoes and 60 degrees for melons) at a 2.5-inch depth. Check the temperature at about 11:00 a.m. to get a good average temperature. Check for several days in a row to ensure the temperature is stable. (Ward Upham)
Organic Sources of Nitrogen Fertilizer
Product Analysis Pounds/100 sq. ft. Notes
Blood Meal 12-0-0 5 - 10 Can burn plants if overapplied.
Cottonseed Meal 6-0.4-1.5 10 May have pesticide carry over unless labeled as
Soybean Meal 7-2-1 8
Feed stores will often sell these products. Colorado State University has an excellent publication on organic fertilizers at http://cmg.colostate.edu/gardennotes/234.pdf (Ward Upham)
Spring Has Sprung - Eastern Tent Caterpillars
In years where ETC hatch was on the early side, larvae had to content themselves by nibbling on swollen leaf buds. (See photo)
This year, budbreak occurred March 12 --- well ahead of egg hatch. Thus, the “current salad bar” is filled with young tender foliage for larvae to feast upon.
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
Mar. Mar. Mar. Mar. Mar. Mar. Mar. Mar. Mar. Mar. Mar. Mar. Apr.
20 26 21 29 30 16 28 23 31 23 14 30 7
What does this mean for homeowners with landscape interests? If they have previously experienced ETC, their biggest objection likely will be the eventual appearance of unsightly web masses (“tents”) which are restricted to branch crotch areas. Currently, the feeding damage attributable to small hatchling caterpillars (barely 1 mm in length) is virtually undetectable. In several weeks after larvae have increased in size, their enlarged “tents” will become more readily visible. The most effective removal of tents within arms’ reach can be accomplished by simply “finger-raking.” Do this during the day when the night-foraging caterpillars are clustered “at home” within their tent. Thus, both the webbing and caterpillars can be disposed of.
Alternatively, let them be. While some defoliation caused by larger caterpillars may eventually become apparent, they will complete and cease their yearly feeding phase in early May. Soon thereafter, leafless branches will rapidly refoliate, thus restoring a normal appearance. (Bob Bauernfeind)
Contributors: Bob Bauernfeind, Entomologist Ward Upham, Extension Associate