For 24 years I have been obtaining and germinating seeds for my commercial palm and cycad nursery. I would estimate that I have germinated several hundreds of thousands of
palm seeds. Every grower will have his own technique or viewpoint. Below is a summary of important points that I think every palm enthusiast or grower should consider when germinating
seeds of palm trees..
Decide Which Seeds To
Germinate
Have a plan for what you are trying to accomplish, and select your seeds
accordingly. Palm tree care begins with picking the right
species to grow.
Select species that will do well in your locality.
Obtain the appropriate number of seeds for your needs.
Always identify the seeds by species, source, and date when you collect or receive them. Don’t “throw everything into a bag to figure out later”. You’ll undoubtedly forget what is what.
Be
aware that there are regulations on the importing and international
sale and trade of seeds. Often, phytosanitary permits are
needed. Sometimes, with Endangered Species, a CITES permit might
be required, even on species of palms. Assume it is necessary
for cycad seeds and refer to specific CITES laws.
Pritchardia
macdanielsii, immature seeds.
(Click photo to enlarge)
.
Butia capitata, mature seeds.
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Get High Quality Seeds
Best results usually come from fresh seeds collected by the grower himself. Only collect ripe seeds. Avoid immature, green seeds. Ripe seeds have mature fruit color and are “ready to drop”.
If purchased, obtain seeds from a reputable dealer. An unscrupulous broker may intentionally or unwittingly give seeds a false or a more “sellable” species name to facilitate the sale. You will be unaware of this problem for some time. Such “mistakes” have led to great confusions with
species of palm trees, especially with recent introductions from Madagascar.
When you find a good seed broker, stick with him. He wants your repeat business.
If purchased, inquire about the age of the seeds. Seeds from distant lands can take months to get into your hands. Except for his source, a seed broker will usually share information he knows.
Poor germination results are usually the result of old or poor quality seeds.
Obtain a USDA Import permit if you plan to import seeds internationally
Clean Off The Seed's Fruit
Before your seeds are shipped to you, insist the fruit is removed to avoid confiscation by the USDA.
Likewise, clean fruit from seeds you are bringing into your state or into the
country.
Rot problems may develop when sewing seeds if fruit is left on the seed. Dry the seeds prior to shipping or transport.
Wear gloves when cleaning fruit on some species such as
Caryota and Arenga.
Seeds germinate better with the fruit off and there are less fungal problems.
Fruit contains certain germination inhibitors. Cleaning of the fruit eliminates these inhibitors.
Checking Authenticity Of
The Seeds
This is one of the hardest things to do. You want to verify that the seeds received are truly what you thought you were purchasing. The same applies to seeds collected in habitat.
In habitat, either at the time or later, try your best to identify the species collected.
On shipped seeds, utilize references with seed morphology such as
"Genera Palmerum" to verify authenticity of the seed you have received.
Float
test
(Click photo to enlarge)
Checking Viability Of Seeds
Obtained
Depending on the species, seed viability varies from several weeks to six to twelve months. Small seeds typically have shorter duration of viability. Understory and more tropical seeds likewise have a shorter time from ripening to loss of viability. As anticipated, seeds that are from more arid habitats typically have longer viability windows.
Check the seed’s general appearance. Good seeds look fresher and feel heavier in the hand. Old seeds look desiccated and feel lighter.
Check seed size. If you know what a seed is should look like and seeds received are much smaller, either you have bad seeds or another species.
Pinch
Test: Viable seeds never collapse when pinched between your thumb and forefinger. If the seeds do collapse, they are either immature seeds or they are old, desiccated seeds with internal air cavities from rot to the embryo or endocarp. Discard such seeds.
Float
Test: Viable seeds invariably sink to the bottom when soaked in water and bad seeds float for the reasons described above. This is providing that any outer fibrous covering layer of the seed has been removed. There are a few exceptions, but “floaters” usually do not germinate.
Cutting a representative seed in half may reveal any early rot or desiccation problems.
Soaking The Seeds
Seeds
of palm trees recently cleaned of their ripe, supple fruit do not need to be soaked.
Seeds shipped internationally or from a broker invariably benefit from a 24 hour soak in clean water. Some growers advocate chlorine free water for soaking.
Soaking prior to sewing gives the seed a “jump start” and helps revitalize older seeds. With short-lived embryo viability time-windows, such “rehydration” may be the difference between success and failure.
Soaking may be eliminated if one is utilizing an effective automatic and intermittent misting system. With most conventional techniques, however, soaking will prove advantageous.
Soaking may protect the seed from future inadvertent under-watering after sewing.
Over-soaking will produce bubbles from fermentation of fruit remaining on the seeds. If longer soaking periods are used, change the water daily.
Community pot, palm
seedlings.
(Click photo to enlarge)
Germination Techniques:
Community Pots Or Beds
This is a method by which seeds are sewn in a container or bed, typically many seeds placed side by side in the germinating soil.
Good for day to day observation and offers a grower the opportunity to remove seedlings at will.
Advantages: Easy observation, erect seedlings, good air circulation, easy application of chemicals or fertilizer, application of bottom heat, and independent removal of seedlings as needed.
Disadvantages: Somewhat more difficult to set up, potential for less heat or humidity, greater desiccation risk, chance for collateral contamination by fungus.
Most frequently used technique by commercial growers.
Germination Techniques:
"Baggie" Technique
An easy technique of placing seeds with some slightly damp moss into a transparent plastic baggie and putting the baggie in a warm environment, such as near a water heater.
Advantages: improved humidity, inexpensive, simple, space efficient, mobile, and good for small numbers of seeds
Disadvantages: Poor visibility, twisted seedlings, potential for rapid fungal demise, lack of ventilation, inferior light, risk of under-hydration without warning, and need for timely removal when ready or one gets “seedling spaghetti”.
Preferred technique by some hobbyists.
Specialized Germination
Procedures
This includes special procedures done to particular species of palm seeds to improve poor germination results from standard techniques. Although successful for a few species, in general these practices are never needed for most species.
However, there are some special rules in palm tree care and
germination.
“Plucking out the eye” of a large coccoidal seed of species such as
Jubaeopsis cafra. In skilled hands, this technique has been reported as successful.
Utilizing very high heat for promoting germination of some genera such as
Acrocomia and Lemurophoenix.
Germination of Borassus species in extremely deep containers to have room for the large and deep root radical.
Germination Environment
A temperature/humidity controlled greenhouse environment is ideal. This offers more heat, higher low temperatures, and more consistent humidity. There is also less risk of predators, weed contamination and weather-related problems.
A simply constructed germination box made out of
styrofoamwith a plastic lid can be constructed cheaply and work well. It is ideal for the hobbyist. A simple warming device such as a light bulb can be utilized.
If not utilizing a greenhouse or germination box, provide your seeds with the warmest area possible with good humidity and away from direct, hot sunlight.
Humidity levels of 60 to 70% are ideal. Avoid overly damp locations or rot will develop.
Heating
mats
(Click photo to enlarge)
Utilization Of Bottom Heat
This is a system of utilizing artificial heat below the community pot to accomplish or accelerate germination.
Commercial heating mats are available with thermostat controls.
Advantageous for most species. Speeds germination. Is not inexpensive to use.
Bottom heat requires a flat surface to function. It is best to shield loss of heat from the bottom of your mat. The distance from the seeds to bottom heat is critical. If too close it may overheat seeds.
For species from colder natural habitats, bottom heat may diminish germination rates and be totally unnecessary.
It will increases water requirements and/or frequency of misting.
A thermometer should be utilized to verify optimal medium temperature.
Be
aware that old mats present a fire hazard. Mats should be
replaced when they are old or show signs of deterioration.
Maximum-minimum
(high-low) thermometer.
(click photo to enlarge)
Simple Outdoor Germination
This means germinating outdoors in a small pot or the garden, nothing fancy. This can be successful with many species in you live in an area that gets adequate heat and not too cold. One should avoid direct sunlight on most species and keep the soil somewhat damp.
One follows many of the guidelines outlined elsewhere in this article. This can be done simply under a bed of mulch in the garden.
Outdoor germination can be successful on many of the cooler growing species of the genera
Howea, Chamaedorea, Butia and Parajubaea.
Coarse
peat moss.
(click photo to enlarge)
Coarse
sand, # 12 grit
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Germination Medium/Soil
It must provide a root substrate, moisture, nutrients and aeration.
It is ideally loose enough for easy penetration of germination
radical.
It should accept water easily and not dry out too quickly.
There are various opinions on the ideal mix. The mix can be made by hand or purchased as “germination mix”. Typically used are mixtures of perlite and peat moss in a 2:1 or 3:1 ratio.
Wetting agents are often added to medium to help with watering.
Pure peat moss can be used but can turn into a hard block if ever allowed to fully dry out.
Other mediums: Sphagnum moss, sand, shavings, etc.
Perlite
(click photo to enlarge)
Watering
Watering once a day in a greenhouse environment is usually adequate. Outdoors, keep the medium mildly moist.
Watering frequency varies with water holding capacity of medium and the ambient temperature/humidity. Sand needs less frequent watering while pure perlite more frequent watering.
Automated misting systems are available but not typically needed. Beware of “over-watering” which can lead to rot problems and damping off of the new leaf.
Water requirements are increased with bottom heat.
Ideal Temperature For
Germination
For most species, soil temperature of 80 to 85 degrees Fahrenheit seems to be ideal. This can be accomplished using bottom heat or a heated greenhouse.
Cold temperatures (day or night) can slow or prevent germination.
Excessive bottom heat can be damaging to a seedling’s roots.
Once then first leaf spear is showing, seedlings can be removed from the bottom heat if you wish. However, repotting should wait (see below).
There are species from colder areas that prefer cooler germination temperatures.
Fertilization Of Seedlings
This can be beneficial after germination has occurred.
It is best to utilize dilute fertilizer solutions. Some would combine a fungicide with the fertilizer.
Fungal Problems With
Seedlings
This can occur at any time. It is known as “damping off” and can be recognized by seedlings quickly turning brown and wilting.
Can travel quickly to adjacent seedlings or from pot to pot.
Requires timely use of appropriate fungicides. I use a product named Daconil.
Prophylactic usage of fungicides can prevent.
Repotting Of New Seedlings
Typically when at least one fully formed leaf exists. Ideally, I wait for the second or third leaf.
Most vulnerable time for seedling demise is when doing the initial transplant.
Seeds often geminate sporadically. Therefore, one may need to harvest seedlings that are ready and place remnant seeds back into the community pot for further germination.
When first repotting the new seedling, introduce it into a very open seedling mix that offers easy penetration of the new roots.
Watch for desiccation with transplanted new seedlings. Typically need for frequent misting to reestablish. Use of “anti-transpirants” may be useful.
Time Needed For Germination
Even for one species, germination times are so variable that predictions and generalizations are almost meaningless. At best, one could state that some genera or species germinate more quickly than others. Germination times are dependent on all factors discussed above and vary from one batch of seeds to the next.
Commonly accepted “slow” genera to germinate include
Acrocomia, certain Syagrus, Howea, Jubeaopsis and Parajubaea.
With no success for six to twelve months, it is best to check your seeds with a pinch test. Often it is found that all the seeds are rotten and need to be discarded.
Difficult Seeds To
Germinate
This problem is magnified if old, marginally viable or immature seeds are used.
More apparent with less than optimal germination techniques.
Examples:
Acrocomia, Jubeopsis, Parajubaea, Lemurophoenix
and Voaniola,
Easy Seeds To Germinate
Some seeds are definitely easier to germinate than others.
Examples include genera such as
Archontophoenix, Areca, Chamaedorea, Pinanga,
Pritchardia, Sabal and Veitchia.
Overall Results
Most dependent on getting fresh, viable seeds.
Also dependent on technique and diligence of nurseryman or hobbyist.
If one actively attempts to germinate many species and gets seeds from all around the world, an overall germination rate of 25% or greater would be considered good.
For some species near 100% is the rule.
For others, 10% would be phenomenal.
Community pot, palm
seedlings (older).
(Click photo to enlarge)
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