Title: TropicLine
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Permanent Link: http://ufdc.ufl.edu/UF00089450/00015
 Material Information
Title: TropicLine
Series Title: TropicLine
Physical Description: Serial
Language: English
Creator: Fort Lauderdale Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida
Publisher: Fort Lauderdale Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Ft. Lauderdale, Fla.
Publication Date: December 1998
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Bibliographic ID: UF00089450
Volume ID: VID00015
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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TropicLine December, 1998 http://flrec.ifas.ufl.edu/tropicline/Volume%2010(3-4).html


Horticulture Newsletter of the University of Florida Fort Lauderdale
Research & Education Center

Volume 10, Number 3-4 December, 1998
Editor: Alan W. Meerow Ch' i 1o, iL T. Waddill, Dean, Cooperative Extension

Save Money Using Compost in the Growing Substrate

Kimberly A. Klock-Moore
Floriculture & Mineral Nutrition

Approximately 15% of the sewage sludge or biosolids produced from wastewater treatment is composted. However,
composting biosolids and yard trimmings produces a product that has the potential to be used to grow a wide variety
of plants.

Previous work at the University of Florida Fort Lauderdale Research and Education Center has shown that impatiens,
petunia, begonia, snapdragon, dianthus, marigold, and vinca plants can be grown in 4"pots filled with media
containing 60 to 100% compost made from biosolids and yard trimmings. Plant growth in compost is as good as or
better than growth in a standard Canadian peat: vermiculite: perlite medium. One reason for greater plant growth in
media containing compost is that compost tends to have complex organic compounds that break down slowly
providing a nutrient reserve for plant growth. Furthermore, biosolids are known to be a nitrogen rich material that
when composted will release significant concentrations of nitrogen. Considering that compost provides nutrients, it
would seem logical that fertilization rates could be reduced when compost is incorporated into the growing medium.

Experiments conducted in spring 1998 with impatiens 'Accent Orange' investigated the growth of plants grown in 0,
30, 60 or 100% compost and fertilized with either 0.5, 1.0, 2.0, or 4.0 g per 4" pot of 13-13-13 Nutricote (6 month).
Plant size was determined 40 days after transplanting (size is average of plant height and plant width).

Results (Table 1) show that plant size increased as fertilizer rate increased from 0.5 to 4.0 g per pot. Plant size also
increased as the percentage of compost in the medium increased from 0 to 100%. Interesting plants grown in 0%
compost with 4 g of Nutricote produced plants that were similar in size to plants grown in 30% compost with 0.5 or
1.0 g as well as plants grown in 60% compost with 0.5 g. Plants grown in 100% compost with 0.5 g were larger than
all of the plants grown in 0% compost.

The recommended fertilizer rate for bedding plants is approximately 3 per pot. The 0.5 g less than one-quarter the
recommended rate. Based on a cost of $13.95 for a 5 lb. box of Nutricote it would cost $12.56 to fertilize 500 pots at
the 4 g rate but would cost $1.40 to fertilize at the 0.5 g rate. This works out to be a saving of $11.16. You also can
figure that to purchase a 3.8 cu ft bale of Pro-Mix costs $19.25 and will fill approximately 271 4" pots at a cost of $
0.07 a pot. However, compost is sold at a cost of $6 to 7 per cu yd. One cubic yard would fill approximately 1929 4"
pots at a cost of $0.003 a pot. It is evident that the use of compost can save money when growing bedding plants.

Further research needs to be done on the growth of other plants in compost as well as the post-production longevity of
plants grown in compost and the fate of chemicals (growth regulators, insecticides, herbicides, etc.) applied to media
containing compost. Growers should be aware that when using compost, they should purchase the compost product
from a reputable source and that the compost is properly aged. They also should be aware that there are many
compost products on the market. All of this research has been conducted on composted biosolids and yard trimmings

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obtained from the Solid Waste Authority in Palm Beach County. Different results may occur with other compost
products or "home-made" composts.

Table 1. Impatiens 'Accent Orange' final plant size.

of Compost





Fertilizer Final Plant
Rate Size (cm)

















Pindo Palm (Butia capitata) Seed Germination Revisited

Timothy KBroschat
Horticultural Physiology

Butia capitata is a cold-hardy palm commonly grown as a landscape ornamental in southeastern United States, as
well as in California and Arizona. Butia fruits have an orange fleshy, but fibrous mesocarp and a hard, stony endocarp
containing one to three seeds (Uhl and Dransfield, 1987). The "seeds" planted by nurserymen and previous
researchers are actually endocarps, and when treated like other palm seeds, germinate very slowly and erratically over
W ~ ~ "2LI

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a 2-. ear period. This poor germination has been
aulnbuted to dormancy (Carpenter, 1988) and to the
thick. impervious seed coat (Sento, 1976).

Carpenter (1988) found that temperatures of 40 oC were
optimum for germination in this species, and that the
"seeds" responded positively to an after-ripening period
ol' 3I to 150 days. He showed that mechanical or acid
scairi ication, followed by soaks in gibberellic acid
( GA ;) or deionized water did not improve germination
time or percentage for this species. The purpose of this
study was to evaluate endocarp removal as a method of
enhancing Butia seed germination.

Materials and Methods

Experiment 1. The orange, pulpy mesocarp was removed from the mature fruits of two Butia capitata trees. These
cleaned" seeds (endocarps) were air-dried at -25 oC for two days. Five replicate lots of 100 endocarps each were
subjected to the following germination treatments: 1.) immediate planting of the cleaned, intact endocarps; 2.)
after-ripening storage of cleaned, intact endocarps in slightly moist sphagnum peat in polyethylene bags for 150 days
at 23 0 C prior to planting; or 3.) immediate planting of seeds obtained by cracking the endocarps in a vise. Endocarps
in this seed lot contained an average of 2.3 seeds per endocarp. Propagules were dusted with thiram fungicide prior to
planting or storage. Propagules were planted in flats using a 1 sphagnum peat : 1 perlite (v:v) medium with 2 mm of
medium covering the tops of the propagules. Flats were maintained under intermittent mist in a greenhouse with
temperatures between 23 and 38 o C. The number of seedlings emerging each week was counted for each replicate.
This experiment was terminated after no seedlings emerged for 4 consecutive weeks (17 months).

Experiment 2. Treatments and sample sizes in this experiment were identical to those in Experiment 1, but the
propagules were germinated in polyethylene bags filled with moist sphagnum peat as described by Carpenter (1988).
These bags were placed in a growth chamber maintained at 40 o C. Each week the contents of each bag were dumped
into a tray, the germinated seeds counted and removed, and the ungerminated seeds and medium replaced in the bag.
This experiment was terminated after 11 months.

Experiment 3. Treatments were similar to those in Experiment 1, except that seven replicate lots of 50 endocarps were
germinated in flats maintained in a growth chamber set at 34 oC. After 56 weeks, a growth chamber malfunction
forced us to move the seed flats into the greenhouse used in Experiment 1. This experiment was terminated after 17

Experiment 4. This experiment differed from Experiment 1 in that four replicate lots of 50 endocarps were
germinated in seed flats maintained at 40 oC in a growth chamber. The after-ripening storage time was 120 days
instead of 150 days as in the other three experiments. This experiment was terminated after 7.5 months.

Results and Discussion

Experiment 1. Seeds with their endocarps removed began to germinate after 7 weeks (Fig. 1A). Endocarps that were
not stored began to germinate after 47 weeks, while none of the after-ripened endocarps had germinated when the
experiment was terminated after 17 months. The final germination rate for seeds planted with their endocarps
removed averaged 133.6 seedlings per 100 endocarps, versus 0.8 for endocarps planted intact and without storage
(Table 1).

Experiment 2. When endocarps and seeds were germinated in slightly moist sphagnum peat in polyethylene bags,
most of the seeds without endocarps rotted. However, intact endocarps were generally unaffected by this seed-rotting
fungus. Thus, this germination method is not suitable for seeds without endocarps. Final germination rate for
after-ripened intact endocarps was 41.4 seedlings per 100 endocarps, versus 37.8 for non-after-ripened endocarps, a

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non-significant difference (data not shown).

Experiment 3. Very little germination occurred in the growth chamber at 34 o C, during the first 56 weeks (36 weeks
for after-ripened endocarps, due to later planting) (Fig. 1B). After 56 weeks, germination rate increased sharply
following their transfer to the greenhouse with a maximum temperature of 38 o C. Time to 50% of final germination
rate did not differ significantly among treatments, but final germination rate was significantly higher for seeds with
endocarps removed than for intact endocarps (Table 1).

Experiment 4. Time to 50% of final germination rate in a seed flat maintained in a 40 oC growth chamber did not
differ among treatments, but seeds without endocarps had significantly higher final germination rates than intact
endocarps (Table 1, Fig. 1C).

These experiments showed that after-ripening storage of endocarps did not improve germination rate nor decrease
germination time as reported by Carpenter (1988). Experiments 1, 3, and 4 each differed in some way from
Carpenter's experimental design, but Experiment 2 followed his design and still did not show an improvement in
germination time or rate for after-ripened seeds.

Germination rate was greatly increased by removing the endocarps. Since each endocarp contains from one to three
seeds, germination rates of over 100 seedlings per 100 endocarps are possible with this method. Although
germination of two seedlings from a single intact endocarp was observed once by the author, such seedlings cannot be
physically separated and grown as normal single-stemmed palms.

As in most other palm seed germination studies (Broschat and Donselman, 1986; Carpenter, 1988; Nagao, et al.,
1988), high germination temperatures were superior to lower temperatures. Experiments 3 and 4 were performed in
34 and 40 oC growth chambers, respectively, but little germination ever occurred at 34 oC. An average of 12
seedlings per 100 endocarps germinated after 56 weeks at 34 oC, versus 82 seedlings after 22 weeks at 40 oC for
seeds without endocarps (Figs. 1B and 1C).

Although the endocarps in these experiments were individually cracked in a vise, commercial nut crackers have been
successfully used for this purpose in Brazil (L. Van der Ven, personal communication). Endocarps were found to
crack with less seed damage if they were allowed to air dry for two to three days following mesocarp removal.

In summary, endocarp removal appears to be a highly effective method for improving germination of Butia capitata
seeds. This technique was not successful, however, when seeds were germinated in polyethylene bags filled with
damp sphagnum peat. After-ripening storage does not appear to provide any advantage for the germination of Butia

Literature cited

Broschat, T.K. and H. Donselman. 1986. Factors affecting storage and germination of Ch',iy i/i, '1i,,1,
lutescens seeds. J. Amer. Soc. Hort. Sci. 111:872-877.

Carpenter, W.J. 1988. Seed after-ripening and temperature influence Butia capitata germination. HortScience

Nagao, M.A., K. Kanegawa, and W.S. Sakai. 1980. Accelerating palm seed germination with GA, scarification,
and bottom heat. HortScience 15:200-201.

Sento, T. 1976. Studies on the germination of palm seeds. Memoirs of the College of Agric., Ehime Univ.

Uhl, N.W. and J. Dransfield. 1987. Genera palmarum. Allen Press, Lawrence, Kans.

Table 1. Effects of endocarp removal and after-ripening storage on
germination time and rate for Butia capitata

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TropicLine December, 1998

(23-380 C)


Endocarp removed

Endocarp intact,
not stored

Endocarp intact, stored

Significance (P)


Time z Ratey

42.4 133.6 a

46.0 0.8 b


0.0 b


Growth chamber (340


Timez Ratey

57.6 93.7 a

48.2 15.1 b



19.1 b


Growth chamber


Time z Ra

11.5 82.

17.8 26.



ZTime in weeks to 50% of final germination rate.

YSeedlings / 100 endocarps.

XMean separation within columns by Waller-Duncan k-ratio method, k=100.

- endocarp removed 100-=- endocarp removed
- endocarp intact, not stored --- endocarp intact, not stored
- endocarp intact, stored endocarp intact, stored

"f 40-


5 10 15 20 25 30 35 40 45 50

Figure 1A


0 5 10 15 20 .25 30 35 40 45 50 55 60 65


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endocarp removed
100 endocarp intact, notstored

80- -- endocarp intact, stored



a 20

0 5 10 15 20 25 30
Time safer plnrtinn (weeks)

Figure 1C

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