Seed quality is subject to deterioration over time. The rate at which quality is lost depends on the conditions seeds are exposed to.
Temperature and humidity are primary factors that influence deterioration of seed quality over time. Suppliers, distributors and growers all need to preserve the quality of seed for sowing. The shelf life of seed can be maintained if stored in appropriate conditions.
This is particularly important when a high value seed inventory is maintained
The quality of flower seed can be measured. Various tests help describe the vigour of a particular seed lot. Vigour is the strength of growth of the seed and seedling which is sensitive and can be shown to decline with seed storage time. After a certain period of time the seed lot will have no value to you, despite your best cultural efforts.
Failure to obtain full plug trays of high quality transplants may well be the result of prolonged storage of seed under wrong conditions. Recommendations for storage conditions for flower seed, state that the humidity levels should be 25-35%. This will keep temperatures below room temperature (cooler than 15°C), with an emphasis on lower temperatures if possible, of around 5°- 8°C.
Seed should remain under these conditions until sowing
Seeds take time to equilibrate to storage conditions. Adjustment is affected by the packaging material, seed composition and air movement around and through the seed. Seed sealed in foil packets is only affected by temperature and not humidity. Conditions should be as stable as possible since fluctuations can stress seeds.
It is important to appreciate that seeds of different crops have different built-in shelf lives. The shelf life of seed is like a biological clock that causes vigour to be lost with each tick. It is possible to slow down this clock by providing good storage conditions. Maintaining the correct storage conditions is important for short shelf-life products such as flower seeds.
No matter how good your storage conditions are, minimising time is recommended. Better inventory organization and the rapid transport of seed from suppliers and distributors to growers helps to protect your investment in seed quality. It is therefore crucial to ensure your seed supplier is delivering you “freshness” from the moment the seed is harvested until you receive the packet in your nursery. For this you need confidence that seed has been handled in the best conditions. Good planning of your seed requirements and programming this delivery with your supplier, always achieves the best results and helps protect your investment in seed quality.
Seed quality can deteriorate rapidly without good storage conditions
As an example, Impatiens seed exposed to temperatures above 21°C and humidity above 40% for more than 2 hours can reduce the viability by up to 27% or even induce dormancy!
Storing smaller amounts of seed at a nursery can be managed quite easily. Here are some basic rule of thumb tips:
- The hermetically sealed packets supplied to you from Ball Australia should be kept in a cool dry place until opened.
- Once the seed packet is opened, use seed as soon as possible.
- Note the date opened on the seed packet for reference.
- Reseal immediately after use and return to the cool dry storage place.
- Ideally place into refrigerator set to maintain the temperature between 5°C and 10°C.
- For longer-term storage it is important to handle the seed more carefully and prepare it for storing. Place your opened packets of seed in a jar or plastic container with silica gel to absorb some of the moisture from the air. After about 1 hour the seed should have some equilibrium. Seal the jar or container with the lid. Position the seed along with any un-opened sealed packets in the refrigerator set between 5°C and 10°C.
- It is important to note that to achieve and maintain the ideal humidity of 25-35% for your seed once opened, would require specialist humidification equipment. The best practice is to open the packet immediately before you need to use the seed and reseal the packet with its special seal immediately after use, then place back in the refrigerator.
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