Harvesting your own seeds from fruit and vegetables for propagation into a nursery significantly reduces your costs by over 50 percent. In order to reap the maximum benefit, you must give your plants the help they need to produce healthy seeds. Harvesting and storage techniques require particular attention because they impact seed quality. To achieve the best results, one must harvest at the right time, clean with the proper techniques, and dry and store in optimum conditions. Prior to harvesting, keep in mind the following recommendations.
• Seed Types
If you are planning to harvest your own seeds, then you should avoid purchasing hybrids, which are artificial and usually designed for only one planting season. Instead, purchase heirloom and/or open-pollinated varieties, which are natural and produce crops that yield continuously reproducing seeds. After planting, clearly mark each type with a nametag so you can monitor how different varieties perform.
• Disease Control
Most seeds will germinate and grow to become plants. Some plants will contract disease. During harvesting, do not collect seeds from disease-infected plants; whatever ailment infected a plant will be transmitted to all future ones.
• Seed selection
Select seeds from the healthiest plants. Characteristics such as total fruit yields, size, disease resistance and early fruit-bearing/maturity are reliable indicators of good health. Identify robust plants with a special wooden tag, ribbon or loosely tied string.
• Seed Ripeness
It is advisable to allow seeds to fully ripen before harvesting. Allowing them adequate time to mature enables them to store sufficient nutrients for germination and healthy growth. This will help to ensure that they achieve the best germination yield for the following season.
Dry your seeds before storing. A moisture content of about eight percent is recommended; however, a range of 5-13 percent is also good. You will need to use your best judgment to assess moisture since scientific methods are expensive.
Separate seeds from one another so they can dry evenly. Small ones dry faster than large ones. Caution: drying seeds too quickly will cause them to shrink and crack. The best way to ensure proper temperature control is indoor air-drying.
Once the seeds have dried, put them in an envelope or a breathable bag (e.g., paper or cloth), and place in a dry, cool area. Caution: Do not expose seeds directly to air, as they will absorb the ambient moisture. Also, do not seal them inside a vacuum container because they require minimum air for survival. Optimum storage temperature is between 33oF and 40oF.
Label each bag to allow for simple identification of your different seed varieties. Use permanent ink that is fade-resistant and cannot be easily erased. Note on the label the number of days they were allowed to dry and what the weather conditions were at the time of harvest. After labeling, take about 10 percent of each variety and deposit them in a seed bank. This reserve is your insurance in the event that the remainder becomes infested or diseased.
• Seed preparation at the start of planting season
It is advisable to break dormancy prior to planting. Place the seeds in a freezer for about three hours. After removal, expose them to warm air for about a day. This process helps to achieve optimum conditioning for immediate planting.
• Seed germination test
It is recommended that you test the viability of your seeds in a small area before you begin large scale planting. Using a permanent marker, write the name of the seeds and year harvested on a damp paper containing approximately 10 seeds. Place the dampened paper in a warm and moist environment. Periodically check for the average time it takes to germinate.
The germination rate is determined by dividing the number of seeds that sprout by the total number being tested, multiplied by 100 percent. If you get a germination rate of above 80 percent, your seeds are viable and ready for immediate planting. Rates below 80 percent require additional testing for viability.
Harvesting Three Difficult Seed Varieties for Propagation into Your Nursery
1. Broad beans
Broad beans are a cross-pollinated plant making it difficult to retain its purity. Insects transfer pollen grains of broad beans from nearby environments making it problematic to preserve the integrity of your crop. Taking stringent measures is required if you want to maintain pure seed varieties.
Distancing the plants approximately one-half of a mile away from other varieties is recommended, though it can be challenging. Limited land availability often makes this an impracticable choice. However, buildings, sheds, fences, trees and houses help to reduce insect intrusion.
If you have limited land space and are in close proximity to neighbors growing a different variety, protecting your plants from cross-pollination will be arduous. Shielding your plants with a suitable covering helps to eliminate insects and promote self-pollination.
Make sure to harvest only the seeds from healthy and strong plants. Allow your beans to mature. Pods that are dark brown, dry and wrinkled have reached maturity. Select larger pods for healthy seeds, and then shell them. Confirm they are dry by biting; if they require further drying, place them in a warm, well-aerated place.
Most tomato varieties are self pollinating plants. They will not cross-pollinate because the anthers of a tomato are fused together, resisting cross-pollinating agents such as insects. Its stigma is very short and located deep inside the anthers. To harvest tomato seeds, allow your fruit to completely ripen and select the varieties you want to keep.
Slice each of the selected fruit across the middle and squeeze the seeds and juice into a container. Fermenting the mixture for several days is required to remove the jelly-like coating on the seeds. Fermentation will also help to kill many diseases and remove germination-inhibiting substances.
Harvesting tomato seeds can be challenging because of the fermentation process. Once you have squeezed the juice and seeds into a container, store it in a warm place – about 75-85oF – for three to four days. Regularly check the mixture. Bubbling and the formation of white mold on the surface indicate fermentation. After you observe bubbles, allow the mixture to continue fermenting for one more day, and then pour into a fresh container.
It is crucial to be vigilant of fermentation. Seeds left too long above 80oF will germinate, making storage futile. When they absorb too much water, they begin to bulge. This indicates that internal germination has begun, damaging them for storage.
Marrows, pumpkins and squashes cross-pollinate. Hand pollination of one or more fruits is the only way to protect them for harvesting. This is difficult since it requires higher skilled personnel, is time intensive, and demands close supervision.
Marrow plants have separate male and female flowers. Female flowers are the ones that develop into marrows. Male flowers have a straight stem. You need to be able to transfer pollen grain from male flowers to female ones. It is crucial to protect females from pollen grains of a different variety. Detecting when plants are just beginning to flower requires extraordinary attention.
Identifying which flowers are going to open the following day can be done the night before by distinguishing those that are plumper than the others. They will also have turned from yellow to green. Preventing the flowers from opening is essential to repelling insects and avoiding cross-pollination. Use a thin rubber band to close the petals. The following morning, pick male flowers and use it like a brush to rub the stigma of a female flower. Then, carefully close the petals of female flowers to deter insects. Finally, tie a piece of fabric loosely around the stem of the female flower for easy, direct identification of the hand pollinated marrow.
Leave the marrows to develop and ripen. After harvesting, keep them in a cool, dry place for another 30 days to continue ripening indoors. After one month, cut the marrows in half and remove the seeds, leaving the remainder for normal consumption. Clean the seeds in sisal with plenty of water to remove fibers. Drain the water and spread the seeds on a dry plate. Dry as quickly as possible, but do not expose them to extreme heat. Prior to storing, test whether the seeds have properly dried by bending one in half. If it is sufficiently dry, it will snap instead of bend.