|
 Seed Storage |
When seed extraction and drying have been completed it is necessary to keep the seed under the best possible conditions to ensure that the maximum potential germination and other seed quality factors are maintained. Stored seeds are the primary input of TECHPARK's vegetable cropping programme and are vital links between successive crop generations. In TECHPARK's seed in store represents a significant proportion of the TECHPARK's material assets. |
| Natural Longevity |
| The period of storage may be relatively short , perhaps even only weeks but sometimes it is necessary to store seed for several years. The longevity of seed is primarily dependent on its inherent keeping quality which varies with species. Some species, e.g. onion, Allium cepa, and leek, Allium porrum, are relatively short lived. Sweet corn, Zea mays, and the larger seeded Phaseolus spp., are intermediate, while seed of many genera of the Cucurbitaceae, e.g. Cucurbita spp., are relatively long lived in storage. |
| Seed Storage Period |
The storage period of seed should be defined by TECHPARK as the total time from seed maturity through to sowing, and although a seed-lot can undergo several operations such as cleaning and packaging, or a waiting period while held as stock by a retailer or farmer before being sold or sown, it is important that this total time from maturity through to sowing be regarded as the storage period, because it is throughtout this entire period that the seed is subject to adverse influences of the storage environment. The phases or stages comprising the total possible storage duration of a seed-lot are comprised of some, or all, of the following: |
·Post maturity drying.
·Seed extraction or threshing (outside or under cover).
·Seed cleaning (outside or in buildings).
·Holding storage (seed store or warehouse).
·Seed packaging (usually in purpose-built structure).
·Transit and distribution (all modes of transport and handling stages).
·Marketing (wholesale and retail).
·Point of sale (shop, garden centre or farm supplier).
·Farm storage (from receipt of seed on farm or garden to sowing). |
| Effect of Storage Environment on Seed |
| The two most important environmental factors which can affect seed quality during storage are temperature and relative humidity. In practive the ambient relative humidity plays a major role, firstly because the seed's moisture level is a function of relative humidity, and secondly the incidence of storage fungi and insect pests is largely influenced by the relative humidity of the micro-climate within the seed mass. |
| Seed Storage Technique |
| TECHPARK has a group of professionals for seed storage including control of temperature and relative humidity, management of warehouse, ventilation, refrigeration and dehumidification etc. |
| Storage in Vapour-proof Containers |
The principle is that seed-lots are dried to a moisture level slightly lower than they would be prior to normal open storage, and are then sealed in metal cans, packets or other suitable moisture-proof containers. As a result of this containerization or packaging, each seed-lot is in its own environment and may be stored at ambient temperature and relative humidity for one or two years, or even longer, with little or no deleterious effect on germination. In fact, provided that careful attention has been given to important details such as drying, and the determination of moisture content, and appreciating that different seed-lots can differ in their composition, it is possible that the potential storage life of a seed-lot at 8 per cent moisture content can be doubled if 1.0 per cent more moisture is removed before sealing. |
| Seed Moisture Before Vapour-proof Packaging |
| It is of fundamental importance that seed moisture is reduced to a satisfactory and safe level before the seed is sealed in vapour or moisture-proof containers. This is generally 2-3 per cent lower than for other forms of storage or packaging in non-moisture-proof containers. The reason for this is that the atmosphere within a moisture or vapour-proof container will equilibrate to the moisture level which is in the seeds. This results in a long-term relative humidity which is too high for safe storage. In addition some storage pathogens will become active within the sealed container and the seeds respiration rate will be relatively high. |
| The majority of species grown as vegetalbes have seed with a safe moisture content during sealed storage of between 8 and 9 per cent, but in some species it is less than 8 per cent. |
| Satisfactory moisture levels for seed to be stored in vapour proof containers or packages |
| Family |
Vegetable |
Maximum per cent seed moisture |
| Chenopodiaceae |
Beet, Chard, Spinach |
7.5 |
| Cruciferae |
Cabbage, Broccoli, Cauliflower, Collards, Chinese cabbage, Kale, Turnip, Rutabaga, Kohlrabi, Brussels sprouts, Mustard, Radish |
5.0 |
| Leguminosae |
Snap bean, Lima bean, Pea |
7.0 |
| Umbelliferae |
Carrot, Celery, Celeriac |
7.0 |
| Solanaceae |
Tomato,Hot Pepper, Sweet pepper, Eggplant |
6.0 |
| Cucurbitaceae |
Cucumber, Musk-melon, Melon, Squash,
Pumpkin, Watermelon |
6.0
6.5 |
| Compositae |
Lettuce |
5.5 |
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| View a listing of our current vegetable seed products >> |
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