THE WHEELBARROW THE WHEELBARROW
Mercer County | November –December 2011
Master Gardener meetings are held the third Wednesday of every month at 6:30 p.m. at the Penn State Extension Office — Mercer County
Phone 724-662-3141, fax 724-662-1933, e-mail [email protected]
MASTER GARDENERS & PUBLIC MEETINGS 2011
Next Meetings –, January 18, 6:30 p.m. Note: No December Meeting
Board Meetings – January 4, 6:30 p.m.
Note: No December Meeting
Upcoming Meetings and Opportunities for Educational Hours
January 14, 2012 – Come Grow With Us – All About Gardening
MAKE SURE TO MARK YOUR CALENDARS NOW. For more specifics, please call the extension office at
724-662-3141 or contact Debbie Plant, MG Coordinator at 814-786-9320.
Mercer Master Gardener web site – http://extension.psu.edu/mercer
UPCOMING MG ACTIVITIES
January 14 – Come Grow With Us Seminar –
Gardening From the Ground Up –9:00 a.m. to 3:30.
November 16 – There will be a short business meeting
followed by the annual making of the greens. If you would
like to make a wreath, please let Debbie know by November
11 so she can get the frame. Frames will be provided by the
board. Bob Monske will provide the pine. Please bring
gloves, wire cutters, wires, bows, pine cones, nuts, holly,
other greens or anything you would like to use or share to
decorate the wreaths. Call or email Debbie at 724-3013273 or [email protected] or
[email protected].
Registration begins at 8:00 a.m. Speakers for the day and
topics include: Dennis James – All About Perennials; Steve
Grund – Pennsylvania Rare Plants; Donnajean Enyeart –
Tips on Scrapbooking; Cyndi Fink – Moss and Moss
Gardening; Mindy Swartz – Heirloom and More; Pam
Rodemoyer and Rosalie Palmer – Fairy Thyme.
Registration is due by December 30. The cost is $30. If you
have not received a registration form, please contact the
extension office. If you have any questions, please contact
Debbie.
Holiday Gathering – Lunch and Learn will be held on
Saturday, December 3, at the Comfort Inn, Perry Highway,
Mercer at 11 a.m. A buffet lunch will be at 11:30. Speaker
Cyndi Fink will speak on Native Plants – Flowers and Trees
at 12:30. There will be a gift exchange at 1 p.m. Gifts for
the exchange are to be garden items costing $10 to $15. The
cost is $12 for a MG and $14 for guest. Contact Debbie by
November 25 to register for lunch.
Baked Goods Needed!!
Baked goods are needed for the January 14 Master
Gardener’s educational seminar. Donations suitable for
breakfast such as muffins, coffee cakes, sweet rolls, donuts,
and bread will be gratefully accepted.
Our lunch on that day will be catered.
If you are able to bring a baked good donation to the
seminar please e-mail or call: Jane Martin by December 31
at [email protected] or 724-982-0321. If no answer,
please leave your name and number.
Submitted by Jane Martin
Chairman and Co Chairs - Budgets must be turned
into Debbie by the November meeting. Please email the budget to Debbie if you will not be
attending the November meeting.
NOTE: There will not be a meeting in December.
MASTER GARDENERS’
HARD WORK APPRECIATED
Thank you to the MGs that came on a cold rainy day to help
remove the grasses from the grass garden before construction was
to begin on the building.
Please let me know what you are doing so you can
be recognized in this column and let others know
what is happening in the MG program. Your work
deserves to be recognized.
Cleaning and Disinfecting the Greenhouse
First Steps to a Clean Greenhouse
If you have had re-occurring problems with diseases such as
Pythium root rot or insects such as fungus gnats, perhaps your
greenhouse and potting areas need a good cleaning. Over the
course of growing a crop, infectious microbes accumulate and
algae flourish on moist surfaces harboring fungus gnats and
shore flies.
Attention to greenhouse sanitation and disinfecting are steps
that growers can take now to prepare their greenhouses for the
spring growing season. Some growers wait until the week
before opening a greenhouse before cleaning debris from the
previous growing season. It is better to clean as early as
possible to eliminate over-wintering sites for pests to reduce
their populations prior to the spring growing season. Pests are
much easier to prevent than to cure.
Begin by thoroughly cleaning the floor of soil, organic matter
and weeds. Install physical weed mat barriers if floors are bare
dirt or gravel and repair existing ones. Weed barriers not only
prevent weeds, but also make it easier to manage algae. Avoid
using stone on top of the weed mat that will trap soil and
moisture, creating an ideal environment for weeds, diseases,
insects and algae.
Benches, preferably made of wire, should be disinfected and
pots, flats and trays should be new or disinfected. Bench tops
and work tables should be made of a non-porous surface such
as a laminate that can be easily disinfected. Avoid using bare
wood for these tasks. Hose ends should always be kept off the
floor and growing media kept in a clean area and covered.
Avoid holding plant material and accumulating contaminated
pots, media or debris in the media mixing area. Next, disinfect
the growing and plant handling areas, and irrigation system.
Benefits to Disinfecting the Greenhouse
Many pathogens can be managed to some degree, by the use of
disinfectants. For example, dust particles from fallen growing
medium or pots can contain bacteria or fungi such as
Rhizoctonia or Pythium. Disinfectants will help control these
pathogens. In addition to plant pathogens, some disinfectants
are also labeled for managing algae which is a breeding ground
for fungus gnats and shore flies.
Although disinfecting should be done routinely, timing does
not always permit this extra effort. Take the opportunity to
thoroughly clean greenhouses between crop cycles when
greenhouses are totally empty.
Managing Algae
Algae are a diverse grouping of plants that occur in a wide
range of environments. Algae growth on walks, water pipes,
equipment, greenhouse coverings, on or under benches and in
pots is an ongoing problem for growers. Algae form an
impermeable layer on the media surface that prevents wetting
of the media and can clog irrigation and misting lines, and
emitters. It is a food source for insect pests like shore flies, and
causes slippery walkways that can be a liability risk for
workers and customers. Recent studies have shown that algae
are brought into the greenhouse through water supplies and
from peat in the growing media. Once in a warm, moist
environment with fertilizer, the algae flourish.
Proper water management and fertilizing can help to slow algae
growth. Avoid over-watering slow-growing plants and
especially crops early in the production cycle. Allow the
surface of the media to dry out between watering.
Avoid excessive fertilizer runoff and puddling water on floors,
benches, and greenhouse surfaces. The greenhouse floor should
be level and drain properly to prevent the pooling of water
prior to installing a physical weed mat barrier.
Irrigation Systems
Non-recirculating irrigation systems can be cleaned using a
new product, chlorine dioxide (SelectrocideT). It is labeled for
disinfecting irrigation lines and greenhouse surfaces. To
thoroughly clean irrigation systems, the company recommends
using two consecutive overnight treatments, and then flushing
the system with clear water, making sure to discard the
dislodged debris. SelectrocideT can also be used as a
continuous ultra-low dose treatment.
Greenhouse Benches
If possible, use benches made of wire that can be easily
disinfected. Wood benches can be a source for root rot diseases
and insect infestations. Algae tend to grow on the surface of the
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wood creating an ideal environment for fungus gnats and
shore flies, and plant pathogens can grow within the
wood. Plants rooting through containers into the wood
will develop root rot if conditions are favorable for
pathogen activity. Disinfect benches between crop cycles
with one of the labeled products listed below. Keep in
mind that the following disinfectants are not protectants.
They may eradicate certain pathogens, but will have little
residual activity.
Disinfectants for Greenhouses
There are several different types of disinfectants that are
currently used in the greenhouse for plant pathogen and
algae control. They are quaternary ammonium compounds
(Green-Shield®, Physan 20®, and Triathlon®), hydrogen
dioxide (ZeroTol®, Oxidate®), chlorine dioxide
(SelectrocideT) and chlorine bleach. Alcohol, although
not used as a general disinfectant is mentioned here
because it is used by growers to disinfect propagation
tools. All these products have different properties. If
possible, disinfectants should be used on a routine basis
both as part of a pre-crop clean-up program and during the
cropping cycle.
Organic growers have limited options for disinfectants.
Oxidate® is the only material mentioned above that is
currently listed by the Organic Material Review Institutes
(OMRI), see www.omri.org [2]. Ethyl or isopropyl
alcohol is also allowed under the organic standards.
Organic growers should always check with their
certifying organization before using any material new to
their farming practices.
Quaternary ammonium chloride salts (Green-Shield®,
Physan 20® and Triathlon®). Q-salt products,
commonly used by growers are quite stable and work well
when used according to label instructions. Q-salts are
labeled for fungal, bacterial and viral plant pathogens, and
algae. They can be applied to floors, walls, benches, tools,
pots and flats as disinfectants. Physan 20® is also labeled
for use on seeds, cut flowers and plants. Carefully read
and follow label instructions. Recommendations may vary
according to the intended use of the product. For example,
the Green-Shield® label recommends that objects to be
sanitized should be soaked for 10 minutes, and walkways
for an hour or more. Instructions recommend that surfaces
be air-dried after treatment except for cutting tools. The
label recommends soaking cutting tools for 10 minutes
before use, then using the wet tool on plants. One way to
do this is by having two cutting tools, one pair to use
while the other is soaking.
Q-salts are not protectants. They may eradicate certain
pathogens, but will have little residual activity. Contact
with any type of organic matter will inactivate them.
Therefore, pre-clean objects to dislodge organic matter
prior to application. Because it is difficult to tell when they
become inactive, prepare fresh solutions frequently (twice a
day if in constant use). The products tend to foam
a bit when they are active. When foaming stops, it is a sign
they are no longer effective. No rinsing with water is needed.
Hydrogen Dioxide (ZeroTol®, OxiDate®) Hydrogen
dioxide kills bacteria, fungus, algae and their spores
immediately on contact. It is labeled as a disinfectant for use
on greenhouse surfaces, equipment, benches, pots, trays and
tools, and for use on plants. Label recommendations state that
all surfaces should be wetted thoroughly before treatment.
Several precautions are noted. Hydrogen dioxide has strong
oxidizing action and should not be mixed with any other
pesticides or fertilizers. When applied directly to plants,
phytotoxicity may occur for some crops, especially if applied
above labeled rates or if plants are under stress. Hydrogen
dioxide can be applied through an irrigation system. As a
concentrate it is corrosive and causes eye and skin damage or
irritation. Carefully read and follow label precautions. Note
that OxiDate® is the only product of the products mentioned
in this article listed on the Organic Material Review Institutes
(OMRI) website, in the newly-listed products section.
Sodium Carbonate Peroxyhydrate (GreenClean Granular
Algaecide®, TerraCyte®) Both algaecides are granular and
activated with water. Upon activation, sodium carbonate
peroxhydrate breaks down into sodium carbonate and
hydrogen peroxide. GreenClean is labeled for managing algae
in any non-food water or surfaces. TerraCyte in addition to
being an algaecide is labeled to control moss, liverworts,
slime, molds and their spores and is labeled for use on plants.
Non-target plants suffer contact burn if undiluted granules are
accidentally spilled on them.
Chlorine Dioxide (SelectrocideT) Chlorine dioxide is a new
disinfectant in the horticulture industry for controlling algae,
bacteria, viruses, fungi and other microbial pests on
greenhouse surfaces and in greenhouse irrigation systems.
Currently it is labeled to be used to clean out irrigation lines
with a periodic treatment at a moderate dose or to keep lines
from becoming re-contaminated by treating irrigation water
flowing through the system with a continuous ultra-low dose.
Research continues to be conducted on this product to expand
its use in the industry.
Chlorine bleach. There are more stable products than bleach
to use for disinfecting greenhouse surfaces. Chlorine bleach
may be used for pots or flats, but is not approved for
application to walls, benches or flooring. When used properly,
chlorine is an effective disinfectant and has been used for
many years by growers. A solution of chlorine bleach and
water is short-lived and the half-life (time required for 50
percent reduction in strength) of a chlorine solution is only
two hours. After two hours, only one-half as much chlorine is
present as was present at first. After four hours, only onefourth is there, and so on. To ensure the effectiveness of
chlorine solutions, it should be prepared fresh just before each
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use. The concentration normally used is one part of household
bleach (5.25 percent sodium hypochlorite) to nine parts of
water, giving a final strength of 0.5 percent. Chlorine is
corrosive. Repeated use of chlorine solutions may be harmful
to plastics or metals. Objects to be sanitized with chlorine
require 30 minutes of soaking and then should be rinsed with
water. Some would say that rinsing is not necessary. Bleach
should be used in a well-ventilated area. It should also be
noted that bleach is phytotoxic to some plants, such as
poinsettias.
Alcohol (70 percent) is a very effective sanitizer that acts
almost immediately upon contact. It is not practical as a
soaking material because of its flammability. However, it can
be used as a dip or swipe treatment on knives or cutting tools.
No rinsing with water is needed.
Disinfectants should be used on a routine basis both as part of
a pre-crop cleanup program and during the cropping cycle.
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Vandiver, V.V., Jr. 2002. Biology and Control of Algae.
University of Florida Extension. Fact Sheet SS-AGR-34.
http://edis.ifas.ufl.edu/AG142 [5]
Updated 2007
Prepared by:
Tina Smith, Extension Educator
Floriculture Program
Dept. Plant, Soils and Insect Sciences
University of Massachusetts, Amherst
Submitted by LeeAnn Suso
Fall catalogs have arrived for Storey
Books. To receive the 50% discount, a
combined total of 15 books must be ordered.
You pay for the books when they arrive. It is not too late to
order books for Christmas. Books make wonderful gifts!
This information is supplied with the understanding that no
discrimination is intended and no endorsement implied. Due
to constantly changing regulations, we assume no liability for
suggestions. If any information in this article is inconsistent
with the label, follow the label.
References
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Aqua-Hort® Copper Ionization of Irrigation Water. http://
www.aqua-perl.dk/ [3]
Bennett, K.C, Sanderson, J.P., Weston, L.A., Weiler, T.C.
2006 Cornell Guide for the Integrated Management of
Greenhouse Floral Crops [4].
Billings, J. (Ed.) How can algae buildup on porous
surfaces in greenhouses be removed? 2000. Greenhouse
Business 6(8):41-42.
Lopes, P. and L. Stack (Ed.) 2005-2006. New England
Greenhouse Floriculture Guide: A Management Guide for
Insects, Diseases, Weeds and Growth Regulators. New
England Floriculture Inc.
Konjoian, P. SelectrocideT chlorine dioxide as a New
Product for the Control of Algae and Other Microbial
Pests in Greenhouse Irrigation Systems. KFES
Newsnotes, Spring 05-1
OMRI Brand Name Products List. 2005. Organic
Materials Review Institute, Eugene, OR. http://
www.omri.org/ [2]
Powell, C. 1993. Disinfectants or Sanitizers and Their
Uses in Greenhouses. Tips on the Use of Pesticides on
Floriculture Crops. Ohio Florists' Association, Columbus,
Ohio pp 78, 79.
Pundt, L. 2000. Algae Management in the Greenhouse.
Yankee Grower. 2(2):5-6.
Rahilly, C. and Thomas P. 1993. Defeat Algae by
Limiting Elements Vital to Survival. Greenhouse Product
News pp 14, 18, July issue.
HAPPY HOLIDAYS
Thanks to all who contributed to this newsletter. I welcome your input and
appreciate the articles. Committee information, activities, programs, tours,
speaking opportunities and interesting news articles are needed for the
newsletter. I will try to keep a list of all meetings and programs that will
be beneficial to you for new information, volunteer and educational
opportunities. To submit an article or information send it via email to
[email protected], mail to Penn State Extension of Mercer Co., 463
N. Perry Highway, Mercer, PA 16137, turn it in at a regular meeting or by
phone 724-662-3141. Deadline for the next newsletter is Dec. 16,
2011.
Penn State College of Agricultural Sciences research and extension programs are funded in
part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S.
Department of Agriculture.
Visit Penn State Extension on the web: extension.psu.edu.
Where trade names appear, no discrimination is intended, and no endorsement by Penn State
Cooperative Extension is implied.
Penn State encourages persons with disabilities to participate in its programs and activities. If
you anticipate needing any type of accommodation or have questions about the physical access
provided, please contact Penn State Extension—Mercer County at (724) 662-3141 in advance of
your participation or visit.
This publication is available in alternative media on request.
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328 Boucke Building, University Park, PA 16802-5901; Tel 814-865-4700/V, 814-863-1150/
TTY.
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