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November 2013 Archives

Good Question: Do you really need to rake all those leaves?

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Here is some really good information for all of you homeowners looking to avoid the leaf raking process this weekend. The real answer to this question is NO, but it comes with one catch......he most important point with fall cleanup is that the tree leaves are not covering a significant portion of the turfgrass canopy. 10-20% coverage of your lawn might be okay, but I certainly would make sure the leaves aren't covering any more than that. Excessive leaf matter on your lawn going into winter is bad for several reasons. First, it will smother the grass and if not removed very soon in the spring it will inhibit growth. Second, it can promote the snow mold diseases. And finally, turf damage from critters (voles, mice) can be more extensive in the spring.

The homeowner basically has three options to make sure that leaves are not covering a significant portion of their lawn:

1) Rake them up or use a blower- compost the leaves or dispose of them

2) Use the bagging attachment for your mower: compost the leaf/grass mix or dispose of

3) Mulch the leaves with a mower (i.e. chop them into small pieces so they will fall into the canopy). This is my preferred option because the nutrients and organic matter will benefit the lawn and soil. Some leaf types have been shown to reduce weed seed germination when mulched into a lawn canopy (maples, others). The leaves of some particular tree species (legumes like honey locust, others) might actually add a significant amount of nitrogen to lawns because these species fix nitrogen from the atmosphere just like soybeans, so higher leaf nitrogen contents in these leaves is possible. Additional resources for these two concepts are here:

tree leaves and weeds.pdf

N content tree leaves.pdf

Take a Survey and Win an iPad Mini

K. Zuzek, UMN Extension

University of Minnesota Extension is looking for feedback from gardeners, horticultural professionals, and other members of the public to help direct future tree and shrub educational programming. Don't delay. Tell your friends. By taking a short 10-15 minute survey, you will be entered into a drawing to win an iPad mini. Find the survey here.

Thanks you for your help in planning future Extension educational programs! If you have questions regarding this survey, please contact: Kathy Zuzek, Extension Educator - Woody Ornamentals, University of Minnesota Extension at (952) 237-0229.

Fall Color up Close

Karl Foord - Extension Educator, Horticulture

The fall leaf color spectacular is alive and well this year, due to a warm fall and clear sunny skys.

I was curious about the variation in colors coming from one tree. The tree in question is Autumn Blaze Maple (Acer x freemanii) 'Jeffersred'. The variation in color is due to where the leaf was located on the tree and how exposed the leaf was to light. Bright light permits the leaf to produce significant amounts of sugars which are needed for anthocyanin (red pigment) production. Thus more light more red color. Another contributor to the color palate are carotenoid pigments providing orange and yellow. The various combinations give the leaves their variation in color.

Consider the following photos and see how many different colors exist in these fall leaves.

Karl Foord

Photo 1: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 2: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 3: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 4: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 5: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 6:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

The next surprise was the beauty of the underside of the leaves not only in terms of color and color contrast, but also because of the architecture of the leaf veins. Consider these photos and the colors we don't see on the upper surface of the leaves.

Enjoy the color of this fall. Because the weather has such a strong effect on leaf color we cannot expect to see the same colors next year.




Karl Foord


Photo 7:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')


Karl Foord

Photo 8:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 9:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 10:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 11:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Karl Foord

Photo 12:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Prevent Snow Mold on Lawns Now


Editors note:

This is a link to an article that Michelle Grabowski wrote three years ago. This is an excellent article and is as relevant this November as it was that past November.

Prevent Snow Mold on Lawns Now

There's Still Time to Dormant Seed Your Lawn

For over a month now I've been receiving questions that go something like this, "I know I missed the best time for seeding my lawn which is mid-August to mid-September. Can I still seed even though it's October and temperatures have been mild?" My response is always the same, "Just wait, dormant seeding in November will be your best option." It is very true that if temperatures are warm during the month of October, you could get some seed to establish prior to winter, but temperatures are unpredictable and could change drastically within a day.


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Photo 1: Tired of your lawn looking like this every spring. Consider dormant seeding this fall to improve your spring lawn quality.Sam Bauer.


So, what do/did you risk by seeding in October? Well nothing really, except the cost of seed. Chances are that a good majority of this seed will germinate prior to winter, and complete loss of seedlings is possible over the cold winter months. Because of this, your time and money are better spent waiting for the appropriate dormant seeding time which is generally mid- to end-November.

Dormant seeding can be conducted with any turfgrass species. This practice involves seeding when temperatures are too low for the seed to germinate prior to winter. Germination prior to winter is bad and seedlings will generally die if they haven't matured. Sometimes it is a bit of a waiting game at this time of year. The trick is to find the time when soils are unfrozen so that seed can be worked in slightly, yet air temperatures must be cold enough so the seed won't germinate. Wait for high daytime temperatures of 35-40 degrees before seeding. You still should be waiting at least two weeks to seed based on the long range forecast for the Twin Cities. Regions of northern Minnesota will be able to seed much sooner, possibly even next week.

Is there an advantage to dormant seeding versus spring seeding? Yes and no. A dormant seeded lawn could mature as much as one month faster in the spring than a spring seeded lawn. This is because some of the germination process actually starts prior to winter in a dormant seed situation, although the shoots still haven't emerged from the seed. When temperatures are adequate in the spring, complete germination occurs. In this case the seed actually dictates when temperatures are warm enough to grow. Just like late-fall, temperatures and weather patterns can be unpredictable in the spring. For this reason, the best timing for spring seeding is difficult to predict, which can delay the timing to actually sow seed. Still, there some negative aspects of dormant seeding to consider. First, because of the spring temperature fluctuations, it is possible to have good seedling establishment initially, but a cold spell during this time will injure these seedlings. Also, there is a greater potential for seed loss over the winter due to erosion and water movement, predation, and decay. These positive and negative aspects should always be considered during this process.

Bob Mugaas wrote a fantastic article in the November 2009 issue of Yard and Garden News. Please visit this article by clicking the link for more detail on the dormant seeding process: Dormant Seeding Lawns

For turfgrass seeding options, have a look at the University of Minnesota Turfgrass Science Page

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