Title: Production times
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00090492/00007
 Material Information
Title: Production times
Series Title: Production times
Physical Description: Serial
Language: English
Creator: Institute of Food and Agricultural Sciences, University of Florida
Publisher: Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: Fall 2008
 Record Information
Bibliographic ID: UF00090492
Volume ID: VID00007
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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IFAS Extension

Fall 2008
Volume 15, Number 3

Save Money on Fertilizers and Water
By Juanita Popenoe

See the newsletter in color at:

Manganese deficiency in Camellia

Plant Clinic Problem of
the Quarter -
We are seeing more micronutrient
problems lately. This may be be-
cause people are holding plants
longer and do not want to push
them with fertilizer. Plants can
survive without much nitrogen
fertilizer, but you must provide
the necessary micronutrients. Me-
dia pH can also affect micronutri-
ent availability-too high a pH
makes many unavailable. Check it
out at:
See all the Plant Clinic diagnoses
culture/plant clinic/index.shtml

With the sharp increase in cost of
fertilizers and the scarcity of water,
you cannot afford to waste any. Yet
many growers are wasting fertilizer
by washing it away with excess ir-
rigation water. Less fertilizer is
needed if you irrigate less and
plants can survive with much less
nitrogen fertilizer than usually
thought as long as you supply
Growers using less water by fol-
lowing Best Management Practices
(BMPs) have found that they also
need less fertilizer. By making your
irrigation system more efficient and
uniform, you can apply much less
water. The BMP Guide at
erBMP.pdf can help you reduce
your water consumption. To man-
age irrigation more efficiently:
1. Use rain gauges to measure pre-

cipitation-FREE water, and
reduce your irrigation appropri-
ately. Not everyone has a rain
shutoff device for their irriga-
tion system, but you can do it
2. Only irrigate as much as plants
need, not a set amount every
time. You can use soil sensors
to determine this, or calculate it
based on evaporation. Details
for calculating are at
although you must know your
potting media water holding
capacity for these calculations.
This is a little work, but worth
it if it saves you money. Check
ught/maximize.htm for details
on maximizing the amount of
(Continued on page 2)

Workshop: Surviving Difficult Times in the Green In-
dustry August 19, MREC. Free Program. Register at http:/
cfextension.ifas.ufl.edu/calendar.shtml. Limited seating.

Hold the Date! Fertilizers and Amendments: What you
need to know to save on water, fertilizer and potting mix. Tuesday Oc-
tober 7, 2008 MREC.

Expanding Your Plant Palette November 19, 2008. Leu Gardens
Orlando. Growers needed for plant displays of new available material too.

(Continuedfrompage 1)
water that gets used by your crop and
m to see how much water your plants really need.
3. Change your potting media to hold more water.
Using more fine material like Canadian Peat or
Calcined clay can hold more water and make it
available to your plant for longer time periods.
Watch out for increased chances of root diseases
if the roots are wet longer though. Research has
shown that adding 11% (by volume) calcined
clay instead of sand to a pine bark media re-
quired half the phosphorus to produce a good
quality plant and reduced water use 25%. Coarse
material holds less water and will require more
frequent light irrigations to reduce water lost out
the bottom of the pot. Do not water all media the
4. Use cyclic irrigation-calculate how much water
your crop needs based on # 2 above, and supply
portions of the total over the day instead of all at
once. Water should never leave the bottom of the
pot if done correctly.
5. Use micro-irrigation for larger pots. Avoid over-
head irrigation unless pots are jammed. Smaller
pots can be sub-irrigated for the best water sav-
ings. If you must overhead irrigate, make sure
your system is uniform (see below).
6. Group plants according to water needs. Plants
that require more water should be in a zone
where you can apply more. Don't water all the
plants with the same amount that is required for
your water hogs. Opinions on plant water needs
can be found at
To make your irrigation system more uniform:
1. Design the system so that the end of the pipe has

the same pressure as the beginning. Pressure loss
in a pipe increases with pipe length. In long
lengths, the end of the pipe should have a smaller
diameter to maintain the water pressure. If you
are irrigating based on water that gets to the
plants on the end of the line when the pressure is
not uniform, you are applying too much to the
plants at the beginning of the line. In Lake
County the mobile irrigation lab can check this
all out for you for free. Just call Bobby Brown at
(352) 343-2481 ext 6 to schedule an appoint-
2. Inspect irrigation orifices at least annually for
wear and clogging. This is a really easy way to
save water.
3. Use windbreaks if you are using overhead irriga-
tion in a windy site.
Ways to save fertilizer:
1. Use media amendments that retain nutrients and
make them slowly available (like calcined clay).
2. Use organic sources like humates to slowly re-
lease nutrients.
3. Sub-irrigated plants should be fertilized at half
the recommended rate. Sub-irrigation has been
shown to produce better plants without any lost
(leached) nitrogen.
4. Base fertilizer application on plant need.
5. Do not broadcast fertilizer over spaced pots.
6. If using fertigation, apply the fertilizer at the end
of the cycle so that the fertilizer is not washed
from the pots by the irrigation water. (this as-
sumes that you are applying water until it runs
out the bottom, which you should not do).
7. Recent communications with researchers has in-
dicated that half the amount of nitrogen fertilizer
(100 ppm) may be used without damaging the
plants as long as the full micronutrient fertilizer
amount is applied.

Production Times is brought to you by:

Juanita Popenoe, Ph.D.
Lake County, Woody Ornamentals/Multi-County
(352) 343-4101

Lelan Parker, M.S.
Orange County, Greenhouse/Foliage Multi-County
(407) 254-9200

This material is provided as one of the many services relating to the educational programs offered
to you by this agency Our statewide network of specialists is prepared to provide current infor-
mation on agriculture, marketing, family and consumer sciences, 4-H, marine science, and related
fields We will be happy to help you with additional information upon request
Use of trade names in this newsletter does not reflect endorsement of the product by the Univer-
sity of Florida, Institute of Food and Agricultural Sciences, or the Florida Cooperative Extension
The Institute of Food and Agricultural Science (IFAS) is an Equal Employment Opportunity
Institution authorized to provide research, educational information and other services only to
individuals and institutions that function without regard to race, color, sex, age, handicap or

Irrigation Systems for Reduced Runoff
adapted from article by J. Sharma, D.Z. Haman, and R.C. Beeson, Jr. in NFREC News

Subirrigation Based Technologies This irrigation
method utilizes capillary action within the substrate
to draw water from a source through drain holes at
the bottom of a container. Successful use of capillary
systems depends on the capillary rise of the substrate.
Substrates used in outdoor production generally have
poor to moderate capillary rise. Thus capillary
systems are generally limited to production of #3
containers or smaller, depending on the location of
roots relative to the bottom of a container. However,
for plants nearing market size, where roots have
colonized the container volume, subirrigation can be
used for most container sizes. By using flooded trays
or capillary mats it is possible to recycle nutrients
along with the water. This results in reduced usage of
water and fertilizer, and in reduced runoff at a

Subirrigation systems are infrequently used for
outdoor production of containerized plants at
commercial nurseries. However several nurseries in
Florida are successfully using subirrigation
principles. The most versatile example in terms of
container size is the Holloway Irrigation System in


use at Holloway Tree Farm. This is an ebb and flow
system on a large scale compared to the more com-
mon greenhouse system (Figure A), in which plants
are placed on an impermeable surface in graded
basins (Figure B) that are periodically flooded for
irrigation. Water depth is adjusted to overcome low
capillary rise, expanding its application beyond #3
containers. Excess water is then returned to the
retention reservoir. Runoff resulting from rainfall is
also collected in the reservoir for future irrigation
use. Consequently, dis-solved nutrients are retained
in the pond, eliminating groundwater and minimizing
surface water pollution due to deep percolation and
runoff, respectively. Nutrients are only released to the
environment during periods of exceptionally heavy
rainfall. As in greenhouse ebb and flow systems,
unutilized nutrients in the retention water are
reapplied at each irrigation event. The amount of
water released from a reservoir strongly depends on
its size and water level management.

Other subirrigation systems like the capillary mat
system (Figure C) also show promise for outdoor as
well as greenhouse applications. Small pots are typi-
cally the most wasteful of irrigation water because
they cannot easily have individual irrigation emitters
in each pot, but the capillary mat system is perfect for
them. Several local growers are finding that it saves
water, fertilizer, and herbicide, but it also takes some
adaptation. Pots with enough holes on the bottom to
allow the water up, finer soil to provide the capillary
spaces for water to move up, and different manage-
ment practices are required.

Take Hold, With Biocontrol
By Lelan Parker

The primary method of controlling pests in ornamen-
tal crops is chemical control. While chemical con-
trol may be effective, its use may lead to pesticide
resistant pests. You must also contend with phytox-
icity, high labor costs and reentry periods. Some-
times there may be an occasional loss of a pesticide
due to removal from the shelf by the producer or
even health hazards. Biological control, also referred
to as biocontrol, is projected to be a solution to some
of these problems. Biological control uses natural
enemies to reduce populations of harmful pests.
Biocontrol is most effective with an Inte-
grated Pest Management (IPM) program. IPM is a
process using a variety of techniques for pairing the
risks between pests and pesticides to achieve long
term control of pests. IPM is not intended to elimi-
nate pesticide applications, but rather provide a rota-
tion of different methods to suppress and control pest
populations. Biocontrol programs are currently
available and used for the management of the
twospotted spider mite, Tetranychus urticae Koch, in
many ornamental production systems. Useful preda-
tory mites for controlling the twospotted spider mite

are Neoseiulus californicus and Phytoseiulus per-
similis. Significant research is still needed for pests
such as thrips, aphids, mealybugs and scales before
biocontrol programs can be implemented. Although
many of the aforementioned pests have good natural
enemies outside the greenhouse, their effectiveness
under greenhouse conditions may be compromised,
or some beneficial insects may not be commercially
Before starting a biocontrol program a foun-
dation must be prepared by first establishing a scout-
ing program. Next, make a detailed list of all poten-
tial pests and methods for management. Also, pre-
pare a list of chemicals safe to use on the crop and
make a subset of these chemicals that are relatively
safe to the beneficial insects you intend on using. Be
sure to find reliable sources for the beneficial organ-
isms and other materials needed. Having a consis-
tent source for guidance is also extremely valuable.
For further information go to:

2008 Planning Calendar
Links to most programs and agendas may be found at: http://cfextension.ifas.ufl.edu or the UF Extension Calen-
dar at http://calendar.ifas.ufl.edu/calendarindex.htm

26-Review & Exam Limited Certification Licenses. Tavares. Contact Maggie Jarrell 352.343.4101.

7-9- Southern Nursery Association Trade Show. Atlanta. http://www.sna.org.
19-Surviving Difficult Times in the Green Industry. Apopka. Contact Maggie Jarrell 352.343.4101.
21-Review & Exam Ornamental/Turf, Private App. Licenses. Orlando. Contact Celeste White
26-Review & Exam ROW and Aquatic Licenses. Tavares. Contact Maggie Jarrell 352.343.4101.

4-Grades and Standards for Growers. DeLand. Contact Kurt Davis 407.295.5133 or Dana Venrick at
25-27-FNGLA's The Landscape Show. Orlando. http://www.fngla.org


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