Guide to cleaning the fruit off palm seeds

Removing the fruit from palm seeds by the easiest, quickest and most cost effective method

The link to buy Juania australis seeds is here: Buy Juania australis seeds

The fruit would eventually rot away in soil, but the problem is that most palm seeds don’t stay viable for any length of time, it is therefore imperative that the fruit, which is often a germination inhibitor, is cleaned off the seeds in a fast and efficient way, so that the seeds can then be germinated as quickly as possible in the nursery.

In this guide we’re focussing on rare and valuable seeds (Juania australis and Pinanga tashiroi), for which care is required to not damage these very expensive seeds. You should note that seeds of many species of palm are incredibly tough and cannot be crushed even with a hammer, an example would be Acrocomia, Parajubaea or Butia ssp., and fruits of these can be easily placed in a bag then trampled under foot until the fruit comes away from the seed, well, the Acrocomia would need a bit more work than that! Nevertheless so many species don’t produce such indestructible seeds, and here we show you how to remove the fruit without damaging these more delicate seeds.

The first step is to try to harvest the seeds when they are fully ripe, picking only the ripe ones and leaving the rest. If you have time at hand, then placing a suspended sheet under the infructescence (bunch of fruit) and waiting for the ripe fruits to fall into the sheet would be the best method. But, in reality we seldom ever have the luxury of time and collection is usually done quickly. In this instance it is far better to cut the whole infructescence and allow the unripe fruits to finish ripenning while still on the infructescence.

Fig. 1. Pinanga tashiroi fruits

Fig. 1. Pinanga tashiroi infructescences, the yellow infructescence with the black fruits is fully ripe, the green infructescence with the red fruits is not yet ripe

The unripe Pinanga tashiroi infructescence (fig 1) was left together with the fully ripe one for 3 days in a warm room, during which time the ethylene gases produced from the fully ripe fruit goes to speed up the ripening process of the unripe fruit. At the same time the unripe fruit draws the remaining water and nutrition out of the green infructescence, had the red fruits been picked off separate then they would have dried out and not gained that remnant nutrition that they needed. All of these fruits went on to fully ripen and the germination test was 100%.

Fig. 2. Juania australis fruits

Fig. 2. Juania australis fruits.

Fig. 3. Scarified Juania australis fruit

Fig. 3. A scarified Juania australis fruit. A sharp knife is used to slice away some of the outer layers of skin and fruit to allow oxygen and water into the fruit.

Fruits of Juania australis (fig 2) have a waxy coating over the skin of the fruit impeding water penetration of the fruit. This also acts as a barrier to oxygen, and therefore slows the oxygenation and decomposition of the fruit by the natural enzymes (pectins) in the fruit. When fruit decomposes it is an effect of oxygenation of the natural enzymes in the fruit to digest it, so when it’s eaten, the animal extracts those nutrients of the fruit, or the fruit decomposes. The skin is the natural barrier to slow this process. We therefore need to damage that skin of the fruit, by bruising or cutting in a process called scarification. Juania australis is the most sought-after cool-tolerant palm species in the world and its seeds are therefore amongst the most expensive seeds in the world. We don’t just knock them about to try to damage the skin, we take great care to not damage the seeds contained. I’ve used a sharp knife to cut away slices of skin and fruit (fig 3) taking care not to cut too deeply and avoiding the seed contained. Once scarified the fruits are left in a warm room for several hours to oxygenate, this starts the decomposition process of the fruit.

The next step requires soaking the fruit in warm (not boiling) water. Some fruit has naturally high levels of pectin enzyme, and therefore decomposes faster. The Pinanga tashiroi seeds were cleaned of fruit within one day after scarification. This was easily done by rubbing the pre-soaked seeds between my hands, then rinsing the cleaned seeds in fresh water, and allowing to become touch-dry in the air. Juania australis fruits are naturally poor in pectin enzyme and therefore require several days soaking and fermenting to remove the fruit. I add additional pectin enzyme to the water, which you can usually buy in a wine-making shop as a white, crystalline powder. One tablespoon full will usually suffice. Normally, when soaking seeds to hydrate them before planting I would say that the water needs to be changed every day. This is because it stagnates (de-oxygenates) and drowns the emerging embryo in the seed. Seeds need oxygen for respiration during germination. Fermenting fruit is different, we don’t change the water, otherwise we would be throwing our pectin enzyme away and slowing the rate of decomposition. The seed, for the most part is protected from the water by the surrounding fruit, and as soon as the fruit falls away we remove, wash, and dry (to touch-dry) the seeds. The cleaned Juania australis seeds (fig 4) should never be allowed to fully dry out.

Fig. 4. Juania australis seeds

Fig. 4. Juania australis seeds, cleaned of fruit, not allowed to dry-out more than simply touch-dry, and they are now ready for germinating.