Germinating Palm Seeds
Not before time, an article telling you what you've
always wanted to know about this ancient craft. Step-by-step instructions.
Stefan Mifsud, 123 Lampuka Street, Paola PLA04, Malta
Chamaerops No.23, Summer Edition 1996
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In my opinion, germinating seeds can be the best part
or the worst part of a palmophile's hobby. lt simply depends on
whether they germinate or not! Three years ago I took up the pastime
of growing palms. I have waited in vain to read a good article on
the subject of seed germination, but during these three years I've
learned much through experience and so decided to write the article
myself. Here is the result of my experiences, and I hope they may
prove interesting and useful to some of our readers.
Palm seeds have three basic requirements in order
to germinate: water, oxygen and warmth/ heat. There must be a good
proportion or balance of all three and care must be taken because
both excess or lack of one of them will cause failure.
Water & Oxygen
Excess water (waterlogging) in the soil mix can result
in the seeds being deprived of oxygen. On the other hand, lack of
water will result in the seeds drying out. I give my seeds a good
soaking at first so that they can absorb as much water as possible.
I then plant them in a well-draining medium (I use sand in the soil
mix). I also keep the seeds close to the soil surface so that they
remain well-oxygenated during incubation. This also means that they
could dry out more rapidly, so I use peat in the mixture (which
serves as a water reservoir) . The seeds are kept moist, NOT WET,
by spraying the pots every three or four days.
Heat
An incubator or propagator is necessary to supply
the relatively high temperatures that most palm seeds require in
order to germinate. I designed and built my own using an aquarium
combined water heater and thermostat. lt is cheap but manages to
maintain a constant temperature of within 2° of 25°C during
the winter months which is satisfactory for many palm seeds, During
the summer, local temperatures rise higher than this. I find this,
to be important for species with desert origins which had not already
germinated at 25°C.
With the exception of palms originating from desert
habitats, the viability of most palm seed is quite limited. This
means that the seed should not be stored but moistened and planted
as soon as possible after they have ripened. Martin Gibbons' book
(Identifying Palms, Apple Press £4.95) gives a good indication
of the viability of many palm species' seed.
There are various sources of seed:
1. Palm trees in public streets and gardens. If you
plan to collect seeds during a vacation in the Mediterranean be
sure to visit during September to November as most of the seeds
ripen around that time. The colour or shade of ripe fruit is different
from that of developing ones. The seeds inside the fruit coat should
be sufficiently hard that you cannot dent them with your thumbnail.
2. Seed merchants. Seed can be bought through the post from seed
merchants. Try Inge Hoffmann, 695 Joaquin Avenue, San Leandro, CA
94577, USA. They should be well soaked in warm water upon arrival.
If palm seeds dry out excessively they tend to lose their viability.
3. Green grocers and supermarkets. Fine for coconuts and dates.
Following is the method which I have developed for palm seed germination.
There are some variations for individual species, see under the
individual headings.
Method
1. Remove fruit layer (if any) on arrival of seed.
A knife may help, but take care not to damage the point where the
seedling emerges from the seed.
2. Soak seeds. Place in a glass or cup of warm water (about 25°C).
Do not put too many seeds in each cup. Put a pinch of hormone rooting
powder (containing fungicide) in each glass, and stir well. Keep
warm in the incubator. Replace water daily with fresh warm water
while leaving a little rooting powder in each cup.
3. While the seeds are soaking prepare the pots and germination
medium or mix. I use well-washed yoghurt containers, 150 or 180m1,
with holes for drainage made in the bottom. The mix is sterilized
by putting it in a large tin, covering it with aluminium cooking
foil, placing this in a pressure cooker with some water, and 'cooking'
it for 20-30 minutes.
4. After soaking: place a 3cm layer of mix in the bottom of each
cup. Press down lightly.
5. Place 3-8 seeds, depending on size, on this bottom layer. Do
not put seeds on top of each other.
6. Fill gaps between the seeds lightly with mix. Place 3cm of mix
on top, and press down lightly. Spray surface with water containing
rooting hormone powder and a suitable fungicide.
7. Incubate until first leaf is seen or germination is otherwise
noted. Keep mix moist by occasionally spraying
with the water solution.
8. Remove germinated seeds from cup taking great care not to damage
the roots or leaves. This is best done by gently removing the contents
of the cup onto a clean surface and using the fingers to separate
the germinated seeds from the others. Be especially careful if the
roots are entangled.
9. Pot the new seedlings individually in small container (e.g..
punctured yoghurt cups) containing peat. Take care that the roots
are not damaged while putting peat between them.
10. Any seeds which did not germinate in (8) are resubjected to
steps (4) to (9). Otherwise if rot or pests (e.g. nematodes) are
noted on these seeds they should be discarded together with the
container.
11. Place seedlings in good light (near a window) but not in direct
sunlight. Keep warm and humid by spraying occasionally. Do not allow
to dry out at any time. Inspect regularly for spider mites which
cause the leaves to turn yellow or brown. Repot every year or two
depending on the growth rate of the palm.
Species that I have so far managed to germinate:
Brahea armata. Source, local public garden.
Single parent tree. Soaking time, one day, since fresh. Mix 50/50
peat and sand. Incubation temperature: 25°C had no effect, but
seeds germinated at 30°C or above. Viability: remains viable
for months.
Washingtonia robusta, W. filifera. As with
B. armata, at above 30°C the seeds germinated rapidly, i.e.
in less than 2 weeks.
Sabal mauritiiformis. Source, local public
garden. Single parent tree. Soaking time, one day, since fresh.
Mix 75/25 peat and sand. Not yet germinated.
Phoenix canariensis, Source, local public garden.
Male and female parent trees. Soaking time one day since fresh.
Mix 75/25 peat/sand. Incubation temperature 25°C. Viability:
remains viable for months.
Phoenix dactylifera. Source, local public garden/commercial
dates. Male and female parent trees. Soaking time one week. Mix
75/25 peat! sand. Incubation temperature above 25°C. Viability:
remains viable for months.
Phoenix roebelenii. Source, local public garden.
Male and female parent trees. Soaking time one day since fresh.
Mix 50/50 peat/sand. Incubation temperature 25°C. Time for germination,
one to two months, not as good results as with previous Phoenix
species. Viability: remains viable for months.
Livistona australis, L. chinensis. Source,
local public garden. Male and female parent trees. Soaking time
one day, since fresh. Mix 75/25 peat/sand. Incubation temperature
25°C. Time to germinate 1 to 2 months. Viability: remains viable
for a couple of months.
Chamaerops humilis. Source, local public garden.
Male and female parent trees. Soaking time one week. Mix 50/50 peat/sand.
Incubation temperature 25°C. Time to germinate 7-9 weeks. Viability:
remains viable for months.
Howea forsteriana. Source, local public garden.
Male and female parent trees. Soaking time one day since fresh.
Mix 75/25 peat/sand. Incubation temperature 25°C. Time for germination:
not yet germinated after 18 months.
Syagrus romanzoffiana. Source, local public
garden. One parent tree. Soaking time one day, since fresh. Mix
75/25 peat/sand. Incubation temperature 25°C. Not yet germinated.
Cocos nucifera. Source, coconut from local
greengrocer! Note: difficult and erratic to germinate. Successful
method: Bought in November on arrival of first imports, since embryo
still viable. Not soaked and not potted. Sprayed well with plant
insecticide, in case of eggs of pests. Incubated at 25°C. Humidity
maintained by spraying daily with water. Also sprayed weekly with
insecticide. Germination evident when white shoot emerged from one
of the three eyes. Kept in incubator until leaf and roots each 10cm
long. Potted in a punctured bucket in a 75/25 peat/sand max. with
half of seed above surface. Rapid growth above 25°C. with direct
sunlight, high humidity and daily watering.
Phoenix theophrastii. Source, Inge Hoffmann.
Soaking time 2 weeks. Mix 50/50 peat! sand. Incubation temperature,
above 25°C. Time to germinate: 1 to 2 months.
Dypsis (was Neodypsis) decaryi. Source,
Inge Hoffmann. Soaking time 2 weeks. Mix 50/50 peat/sand. Incubation
temperature, above 25°C. Time to germinate: 1 month.
Veitchia merrillii. Source, Inge Hoffmann.
Soaking time 2 days. Incubation temperature 25°C. Time to germinate:
during soaking!
Chambeyronia macrocarpa. Source, Inge Hoffmann.
Soaking time I week. Mix 50/50 peat/sand. Incubation temperature
25°C. Time to germinate: 1 to 3 weeks.
Reinhardtia gracilis. Source Inge Hoffmann.
Soaking time 2 days. Incubation temperature 25°C. Time to germinate:
during soaking!
Currently I am still waiting for other seeds to germinate.
I intend to write a sequel to this article when I have collected
more information. Hopefully, in the meantime, others will be inspired
to write about their own experiences. I am sure I will not be the
only reader who is interested.
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