Introduction
Seeds are living organisms in a state of metabolic suspension. Their viability — the ability to
germinate and produce vigorous seedlings — deteriorates from the moment of harvest, at a rate
determined almost entirely by storage conditions. In the hot, variable climates of the
Mediterranean and Middle East, improper seed storage is a widespread and expensive
problem.
Understanding the physiology of seed storage and implementing proper conditions preserves
the investment in quality seed and ensures that planting material performs to its genetic
potential.
The Science of Seed Deterioration
Seed aging is driven by biochemical processes — lipid oxidation, protein denaturation,
membrane degradation — that accelerate with temperature and moisture. The Harrington Rule
provides a practical framework: for every 1% decrease in seed moisture content between 5–
14%, storage life doubles. For every 5°C decrease in storage temperature between 0–50°C,
storage life doubles.
This means that seeds stored at 25°C and 12% moisture content have roughly one-quarter the
storage life of seeds stored at 15°C and 10% moisture. In Middle Eastern conditions where
ambient temperatures regularly exceed 35°C and humidity fluctuates widely, uncontrolled
storage can reduce viability from 95% to below 50% within a single summer.
Practical Storage Guidelines
Temperature control is the single most important factor. Store seeds in the coolest available
space — air-conditioned rooms, underground storage, or refrigeration. Even a household
refrigerator at 4–5°C provides excellent storage conditions for most crop seeds.
Moisture control complements temperature management. Use airtight containers — glass jars,
sealed plastic containers, or vacuum-sealed bags — with silica gel desiccant to maintain low
humidity around the seed. Replace desiccant when it changes color indicating saturation.
Protect from light, which degrades seed coat integrity, and from insect damage, which directly
destroys seed material. Clean storage areas and inspect containers regularly.
Germination Testing
Always test germination before planting, especially for stored seed. The paper towel test is
simple and reliable: place 50 seeds on moist paper towel in a sealed plastic bag at room
temperature. Count normal seedlings after the expected germination period for the species. The
percentage of normal seedlings equals your germination rate.
Adjust seeding rates based on test results. If germination tests at 80% instead of the labeled
95%, increase seeding rate by 19% to achieve the same target stand.
Conclusion
Seed storage is not a passive activity — it is active preservation of your most important
biological input. The small investments in cool storage, airtight containers, and regular
germination testing pay enormous returns in stand uniformity and crop performance.
Key Takeaways
- Temperature and moisture are the two factors that determine seed storage life — control
both.
- Every 5°C reduction in storage temperature approximately doubles seed longevity.
- Airtight containers with desiccant prevent moisture damage in variable Mediterranean
climates.
- Always germination-test stored seed before planting and adjust seeding rates
accordingly.