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not reflect current scientific knowledge
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record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
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Copyright 2005, Board of Trustees, University
Agricultural Research Center, Fort Pierce
Mimeo Report 71-2
Pi HUIvE LIBRARY
A NEW SEEDING METHOD FOR GROWERS
OF TOMATOES AND OTHER SMALL-SEEDED VEGETABLE CROPS
SiNOV 02 1971
Norman C. Hayslip
I.F.A.S. Agricultural Research Center, Fort Pierce 1.FA.S.- Univ. f Florid?
During the 1970-71 season three grower organizations plug-mix-seeded about
1,000 acres of tomatoes through holes cut in plastic mulch covered beds and had
outstanding results in obtaining good plant stands and uniformity. These plant-
ings were made as the result of research carried out by the I.F.A.S. Agricultural
Research Center, Fort Pierce during the past 3 years. Because of growing interest
in this method of seeding, and its success in experimental and commercial trials,
the following information has been prepared for those wishing to make trial plant-
ings. This report is preliminary and based upon research to date. Growers are
advised to make test plantings before attempting plug-mix-seeding on a large scale.
Advantages of plug-mix-seeding over standard seeding methods
1. Provides uniform optimum environment in seed and young seedling zones.
This results in more uniform germination and growth, and more reliable
2. There is no compaction problem with the friable plug-mix soil.
3. Reduces or prevents fertilizer salt damage in sandy soils.
4. Reduces leaching of nutrients during top-watering and rainfall.
5. Provides an adequate, safe level of fertilizer readily available to
the young seedlings.
6. Conserves fertilizer and seeds by placement only where needed.
Formulation of plug-mix for tomatoes -
Jiffy-mix or Redi-earth..........................1 bushel
Magamp, 7-40-6 (medium granules)................ pound
Tomato seeds.................................... ounce
Water..........................enough to slightly moisten
Similar to Cornell Peat-lite mix, containing 1 shredded sphagnum peat
moss and horticultural vermiculite, plus nutrients.
** Magnesium ammonium phosphate with potash. A slow-release fertilizer
manufactured by W. R. Grace & Co.
Jiffy-mix, Magamp and tomato seeds were mixed dry for 5 minutes in a tumble-
type cement mixer. Clean water was added while mixer was running and continued
for 5 minutes afterwards. The amount of water needed will depend upon the method
of applying in the field. Where plug-mix applicators (described later) are used,
mix must be only slightly damp. If mix is too wet clogging will occur. If the
mix is hand applied, more water can be used. The formulation can be stored for
up to 2 days before use (longer during cold weather). Field planting should be
done before the seeds begin to germinate. One bushel of mix will plant about
500 hills, using the recommended cup of loose plug-mix per hill. Hills will
have 2 to 10 tomato plants, averaging 5 to 7 per hill.
Application of plug-mix.
A simple and inexpensive applicator has been designed and used in research
trials. It is hand operated and requires two workers one to operate the
applicator and the other to dump measured quantities of mix into its side
funnel. The cup of loose mix is compacted and driven into the soft plant
bed by means of a ram-rod. The resulting plug is 11" in diameter and about
1" thick. The base of the applicator leaves a shallow saucer shaped depres-
sion around the plug to make watering more effective. One farm organization
built several dozen applicators and used them on about 800 acres. Other growers
are welcome to copy the I.R.F.L. applicator.
Ice cream scoops have been used in place of the applicator. The worker
depresses the soil with the back, rounded side of the scoop, obtains mix from
his bucket with the scoop, dumps the mix into the depression and compacts the
mix with his hand. This method may require less labor, but is less effective
than the applicator. The mix should contain more water if this method is used.
The accumulation of excess fertilizer salts at the exposed soil surface in
holes cut through plastic covered beds has resulted in serious damage to seeds
and seedlings. This problem is worse during periods of hot weather and low
rainfall when evaporation of soil moisture is rapid. In most experiments the
standard method of seeding tomatoes (direct-seeded into the bed through holes
in plastic) has been unsuccessful during August and September. Plug-mix has
given good protection by buffering the damaging effects of these salts, but
injury can occur with plug-mix seeding if the salts become too concentrated.
Watering studies have shown that during hot weather and no rainfall it is
necessary to apply top water every 2 days until the tomato plants are well es-
tablished. The water moves the salts down and away from the seeds and young
seedlings, while maintaining good moisture conditions. The use of sprayer
tanks with nursery type nozzles over each row is an effective method of
watering. Over-head watering may not be necessary, except to keep the plugs
moist, on tomato crops grown on beds without plastic mulch where lower amounts
of fertilizer are used.
One grower reported a cost of about $80.00 per acre for materials, labor
and equipment on staked tomatoes with rows 5' apart and plants spaced 12" apart.
For a regular ground crop with rows 7' apart and plants spaced 24" apart the
cost should be about $40.00 per acre. Since I of the cost is labor expense
these costs would be considerably lowered if the system could be mechanized.
Perlite mulch over plug-mix
One-tenth cup of perlite per hill placed over the plug-mix has given out-
standing results in reducing water loss and fertilizer salt accumulation. Be-
cause perlite is light, it can be blown away, and will float during heavy rain-
fall or during watering. Other heavier mulching materials are being tested.
Perlite should reduce the need for frequent top watering, and some growers
of tomatoes on plastic covered beds may want to try this mulch. A hand operated
perlite dispenser has been made and may be copied by growers wishing to try it.
It is a 3" diameter aluminum pipe with a spring operated metering device to de-
liver the perlite mulch over each plug or seeded hill.
Use of plug-mix for other vegetable crops, and seedbeds
Although most research has been with tomatoes, the plug-mix system has de-
finite promise for other small-seeded vegetable crops, especially hill crops
grown 6" or more apart. Cabbage, pepper and eggplant are examples of crops
which may benefit from plug-mix seeding.
Limited trials in which the mix was drilled in continuous bands have shown
promise for seedbeds. Plant stands have been better and growth more vigorous
and uniform where the soil-mix seeding technique was compared with standard
Tests with onions and carrots indicate better and more uniform stands can
be obtained by drilling the soil-mix. However, the cost may be prohibitive
due to the larger volume of soil-mix required for drilling in a continuous
Agricultural Research Center, Fort Pierce
Mimeo Report 71-2