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!
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.
An incubator or propagator is necessary to supply the relatively high temperatures that most palm seeds require in order to germinate.lt should be at 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.
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.. 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.
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.
Note that not all palm trees require the same germination mehtods