By Alba Portillo
One of the most important factors in preserving seeds is the way we store them. Its quality and viability depend on good storage for future plantings. There are several techniques that can help us, some ancient, others modern. They are available to anyone, even with few resources. From the Casa de Semillas El Re Encuentro, which functions as a coordination of the Network of Guardians of Seeds of Life, in Colombia, we want to share with you some practical tips for this phase of management.
To begin with, the moment the seeds are harvested is very important. We have found that it is preferable to do it in dry and sunny weather, during the day. If it is large grains such as beans and corn, it is better to harvest them when the moon is in its last quarter, to avoid the attack of bugs; Furthermore, at that time the liquid content is lower in the seeds and thus it is easier to dry and store them. Avoid doing it on a tender moon and a full moon.
To harvest the seeds of some vegetables and small grains such as amaranth and quinoa, it is good to remove the entire plant and hang it upside down for a few days; in this way the sap goes down to the seeds, completes their maturation and strengthens the germinative vigor, which is the force that a seed has to be born.
Successful proper storage depends on drying. You have to put the seeds in the shade in a dry and cool place. The technicians tell us that when harvesting the seed it has 15% humidity; it must be lowered to approximately 5% for storage to be successful. In places with a not very humid climate, this is achieved by putting the seeds in trays, newspaper, sacks of fique (vegetable fiber) or blankets. Never on the cement and in the sun directly, because if the seed is heated the germ dies. Drying takes about two to three weeks in mild weather, sometimes longer.
Another fundamental issue in storage is the control of those insects that eat the seeds. A poorly managed seed bank quickly becomes a breeding ground for weevils. These friendly beetles reproduce very fast and are difficult to detect; often the mother already laid her eggs while the seed was still in the plant, through tiny holes.
The seed keeper finds out when adult bugs emerge from the seed by the hundreds to lay eggs in other grains; soon there is nothing left of the seed but dust.
It is useful to know more about this insect, with which every seed grower will share for years to come. The life cycle of the weevil is 4 to 7 weeks. They like heat, not cold. They lay 300 to 400 eggs per mother. They pretend to be dead when threatened. Their incubation stage can be 7 to 15 days and their larval stage is 30 days, which means that they emerge to reproduce at 37 to 45 days. If we harvest grain that has been infiltrated, we will not find out until a month and a half.
Another insect that attacks, more specifically cereal grains like rice, is the moth.
In our network we are experimenting with some techniques to control these insects:
- - We have used the eucalyptus leaves to store the corn, and it has remained healthy. Of course, previously the seed was cleaned, selected, and stored well dry and in a container with a tight lid. Dry plants with strong odors such as mugwort (frame, Ambrosia peruviana), the borrachero (floripondio or huantug, several species of the genus Brugmansia, tribe of the Daturas), the rue (Route graveolens) or absinthe (Artemisia spp.) can also be kept with the seeds.
- - Dipping the seed in ash and soot in some cases has worked well, as has rubbing a little burnt cooking oil; it is important not to put too much oil as the seed gets wet.
- - Cold storage is also very effective. The seed is placed in the freezer for 3 to 5 days maximum. This is a mechanism that works only for small quantities of seeds, otherwise it is expensive to buy the necessary equipment.
- - The most important ancestral technique is smoking. Formerly the seeds were placed in a sovereign or hung on the stove; In this way, every time the seeds were cooked they were enveloped in smoke, which dried them and at the same time avoided the attack of pests and diseases. Today people no longer cook with wood, but there are those who build modern smokers of different sizes and shapes to use this simple and effective method.
Another way to eliminate the weevil is to place the seed in a glass jar that closes hermetically, leaving a free space. A piece of cotton is moistened with a little alcohol, it is lit and carefully placed inside the bottle. The lid is closed, taking care that the cotton does not go out; the fire will consume all the oxygen, the flask will be closed under vacuum, and the insects, adults, larvae and eggs, will die from suffocation. It is a useful system for moderate amounts of seed.
A more advanced form that follows the same logic is curing with methane gas (CH4), ideal for larger quantities of seeds. We learned the method from Fabián Pacheco, who has used it on his farm and disseminated it from the National Institute of Learning in Costa Rica.
- - 2 plastic drums or drums with hermetic lid, 100 or 200 liters;
- - 2 hoses one meter long and ¼ inch in diameter;
- - 1 recycled plastic or glass bottle;
- - implements to connect these elements, putty for tubes or silicone.
The two drums are connected to one of the hoses through their caps, taking care that there are no leaks in the connection, and they are hermetically closed. We can use silicone or tube mastic to secure the hoses to the caps. The second hose is placed on the second drum, also avoiding leaks, on the lid.
In the first drum we will prepare a liquid fertilizer, or biol, using water and elements that ferment such as kitchen waste, leaves, manure, molasses. A good recipe to use later in the garden can be this: 5 liters of molasses, 25 kg of cattle dung, fresh and collected in the morning, ½ pound of yeast, 2 liters of whey or milk, or also a ferment such as chicha or guarapo 1 liter, and some minerals such as rock flour, lime; and 40 to 50 liters of water. These recipes can be modified and can be simpler, it can even be done with just manure; the important thing is that the methane production base, which is manure, is always used.
The anaerobic decomposition of these elements will produce methane gas, which will pass through the hose to the second can, where we will place the dry seed. The insects will die by suffocation, as the methane gas, being heavier, displaces oxygen and poisons the bugs. The second hose evacuates the oxygen and the excess methane to the bottle that we have previously filled with water, to ensure that the gases can escape but the air cannot enter the system. A few days after starting the process we will see how bubbles come out of the hose placed inside the bottle.
It is very important that the seed is well dry before going through this process. And it is essential that the entire system is hermetically sealed. The process takes five to ten days.
A variant consists of placing a stopcock in the first hose, in this way several cans of seeds can be connected one after another while the fermentation of the biol lasts.
An additional benefit of this system is that by storing the seeds in bins, rodents are prevented from entering the grains and they are protected from factors such as relative humidity, which can affect the seed.
It was verified that this process does not affect germination potential at all, on the contrary, according to observations made in the North Node of Nariño of our network, it seems to stimulate germination. The latter will have to be investigated more seriously, but the bottom line is that we already have a good system to clean larger amounts of seeds organically while producing liquid fertilizer.
Storage and conclusions
When the seed is dry, clean and free of parasites, it can be safely stored for a long time. We recommend doing it in glass jars, as they have the advantage that we can admire and monitor the seed. Fernanda Meneses from the RGS Ecuador Coordination House decorates the labels of the bottles with her volunteers, a task that shows the care that the Guardians feel for our Seeds, as we can see on the cover of the article. Another, ancestral option is the storage in "pondos", clay pots with pointed ends that were partially buried in the ground; We ignore the reason, but in this way the seed is preserved extraordinarily well, according to some the reason is the way the energy flows in these containers. In the case of drums, it can be left in the same hermetically sealed drum.
As you can see, it is not necessary to have extraordinary resources to have good seed management. With these simple techniques, small family seed reserves or Seed Houses in our networks can store quality seed and offer this invaluable resource to society.
- Presentation about the methane method by Fabián Pacheco, from the National Learning Institute of Costa Rica.
- Experiments carried out by the Network of Guardians of Seeds of Life, of Colombia, and the Network of Guardians of Seeds, of Ecuador.