Category Archives: Monthly Column

March: Seed Starting and Damping-Off

Preparing for Spring

March is the month when many gardeners begin to think about starting vegetables and ornamental annuals from seed indoors.  While seed-starting can be an economical method for producing plants for home gardening, damping-off can put a damper (no pun intended) on this fun winter gardening activity.

Forms of Damping-Off

Damping-off can take on many forms:

  • rot of seeds prior to germination,
  • rot of seedlings before they reach the soil surface,
  • collapse of seedling stems after emergence followed by plants toppling onto the soil surface (the most classic form of the disease).

Gardeners often blame damping-off on poor seed quality, but disease-causing fungi (and other similar organisms) are the real cause of the problem.  Luckily, only seeds and young plants are susceptible to damping off; older plants are immune to the disease.

Lower stem collapse of Zinnia seedlings due to damping-off.
Lower stem collapse of Zinnia seedlings due to damping-off.

Prevention of Damping-Off

  • Use new or decontaminated growing containers, working surfaces and tools. Damping-off pathogens can survive on inert surfaces.  Rinse items like pots and potting stakes thoroughly to remove soil and then soak them for 20 to 30 minutes in 10% bleach.  Rinse items well after treatment to remove bleach residues.  This treatment works well to decontaminate clay and ceramic containers, but is less reliable for plastic items.  If you have had damping-off problems in the past, discard plastic containers and labels and start with new items.  Also use 10% bleach to decontaminate surfaces where you work with seeds and plants.  For metal tools, use a 30 second dip in 70% alcohol (e.g., rubbing alcohol) to decontaminate or alternatively use a spray disinfectant (spray until tools drip and then allow them to air dry).
  • Use pasteurized soil to start seeds. Pasteurized soils are steam treated which helps kill disease-causing organisms.  Never use garden soils as these typically contain low levels of damping-off organisms.
  • Use high quality, vigorous seed. High quality seed germinates rapidly and resulting plants quickly mature and become immune to damping off.
  • Plant seeds at the proper depth. Check seed packets for information on proper panting depth.  When seeds are planted too deeply, plants mature less quickly and remain susceptible to damping-off for a longer period of time.
  • Germinate seeds at high temperatures. High temperatures stimulate rapid germination and growth, resulting in a shorter period of time when plants can become infected.  Check out heated seed germination mats, which promote rapid plant growth.  They can help prevent damping-off.
  • DO NOT overwater. Damping-off pathogens are more active in wet soils.  Keep soils drier to reduce pathogen activity and limit infections.

For More Information

See the University of Wisconsin Garden Facts “Damping-Off” available at https://pddc.wisc.edu/fact-sheet-listing-all/.

February: the PDDC Brings Education to You

Did you know that the PDDC offers educational programs throughout the state of Wisconsin?

Take a look at our stats from last year:

This year is shaping up to be even busier.

Talks and Workshops

Brian Hudelson, the PDDC Director, designs and delivers custom, in-person presentations to groups throughout the state of Wisconsin.  Target audiences include home gardeners, professionals in the green industry (e.g., arborists and greenhouse producers), and Master Garden Volunteers.

Talks and Workshops

Topics

Brian’s presentations can cover virtually any topic related to plant diseases including, but not limited to, diseases of fruits and vegetables, diseases of trees and shrubs, and diseases of herbaceous ornamentals.

Schedule

You can find Brian’s 2017 presentation schedule here:
2017 Outreach Events Calendar

Check the calendar for the topics, locations, and what educational materials he will provide for each presentation.

How to Book a Talk

If you’d like Brian to give a presentation to your group, contact the PDDC at pddc@plantpath.wisc.edu.

Be aware that Brian’s schedule fills quickly and he is currently booking presentations well into 2017.

Informational Booths

Want to speak with PDDC staff in person, one-on-one?

The PDDC provides informational booths at select events during the year.  Brian, other clinic staff and graduate students from the UW-Madison Department of Plant Pathology can answer your questions on plant diseases and how to manage them.

Informational Booths

The PDDC’s next informational booth will be at Garden Expo February 10-12 at the Alliant Energy Center in Madison, WI.  Garden Expo is one of the largest garden shows in the Midwest and serves as fundraiser for Wisconsin Public Television.

Radio and Television

Brian Hudelson (aka Dr. Death) is a regular guest on Garden Talk with Larry Meiller on Wisconsin Public Radio (WPR), and has appeared regularly on The Wisconsin Gardener on Wisconsin Public Television (WPT).

Radio and TV

Brian will next appear on Garden Talk on February 3, 2017 at 11 am.

Past Appearances

WPR – listen to Brian’s past appearances on Garden Talk on the WPR website.
WPT – watch Brian’s past appearances on The Wisconsin Gardener on WPT website.

Need More Information?

To learn more about PDDC outreach activities, check out the PDDC Clinic Services and Clinic Outreach brochure.

To book Brian for a talk or event, contact the PDDC at pddc@plantpath.wisc.edu.

January: Pruning in the New Year

January is the time of year to start thinking about maintenance pruning for the trees and shrubs in your yard.

While there are exceptions, for many trees and shrubs, pruning during colder weather (when disease-causing organisms and insects are not active) can help minimize infections through pruning wounds.

The “January Thaw”

If you decide to prune, watch for the “January thaw,” when temperatures are warm enough that you will not freeze to death outside, but cold enough for plant pathogens and insects to have limited activity.

How To’s

For details on pruning, see:

Preventing Infections

As an added precaution to prevent infections, consider routine disinfestation (i.e., decontamination) of pruning tools as you prune.  In the best of all possible worlds, you should decontaminate between every pruning cut.  However, due to time constraints, this may not be feasible, but do consider disinfesting tools between every tree or shrub.

  1. Dip them in alcohol. 

    The best and probably easiest way to disinfest pruning tools is to dip them for at least 30 seconds in 70% alcohol (e.g., rubbing alcohol).

  2. Use spray disinfectants.You can also use spray disinfectants that contain roughly 70% alcohol, in which case you spray your pruning tools until they drip and then allow them to air dry.
  3. Dip them in a bleach solution.As an alternative to alcohol, you can dip tools for at least 30 seconds in a 10% bleach solution.

    CAUTION: Bleach is corrosive to metal tools and will induce rusting when used repeatedly.

For More Information:

For addition details on proper pruning, contact your county UW-Extension office or contact the PDDC at pddc@plantpath.wisc.edu.