A beautiful dense and lush green lawn carpet gives every garden that certain something, whether it is laid out as an ornamental lawn or an area for playing and romping. Al
ways use germinable lawn seed. Older seeds can lead to major failures, especially if they have not been stored properly. Therefore, when buying, it is important to pay attention to how long the lawn seed can be stored. Remains well stored, are still germinable for a long time.
Table of Contents
Shelf life of lawn seed
Especially if there are leftovers after sowing or due to bad weather conditions, the grass seed could not be sown as intended, the question can quickly arise: “How long is the seed actually durable?”
Grass seed mixtures are usually produced one year after harvest. From this point on, the grass seed is then still sufficiently germinable for three to four years. Now, it does not mean that seed stored beyond this time is no longer usable. The decisive factor is always proper storage. Of course, it is advisable to test older lawn seed for germination. In addition still some remarks later.
With increasing age of the seed, the germination capacity decreases. After three years, the germination capacity that can still be expected is between about 50 and 70 percent. However, the shelf life of lawn seed is also always dependent on proper storage of the seed. This can preserve the germination capacity for longer. However, if older lawn seed is used, it should be sown more densely than normal. Good to use such seed is also for repairing bare patches in the green area.
Note: Up to 3,000 individual plants of 60 different plant species are needed for one square meter of flowering meadow, a special habitat for insects.
In this country, the quality of lawn seed is regulated by the Seed Marketing Act (SaatG). Thus, the seed must be able to demonstrate certain growth requirements at the time of purchase. Among other things, this includes a minimum germination rate. In the case of subsequent storage, this can decrease differently for the various lawn mixtures.
The year of harvest or production and the best-before date are always indicated on the individual packages. In addition, there is information on whether the seed may have been genetically treated. Of course, the best-before date is always important when buying. This tells you how long the lawn seed can germinate, provided it is stored properly. In DIY stores, discount stores and garden centers, the shelf life of lawn seeds can be affected due to external influences such as increased humidity and high temperature fluctuations, especially in summer.
Tip: When buying, always take a look at the year of filling. The filling should be as fresh as possible, then a higher and longer germination capacity is guaranteed.
Of course, only freshly harvested lawn seed can show the highest germination quality when sowing. With increasing storage time, the germination rate then decreases steadily. However, seed is still germinable after three to four years because the seedling is protected in a starch tray. During the dormant period of the seed, a process takes place within the seed to prepare for possible germination. Only when water is added is this activated. Such processes require a lot of energy and during storage a lot of power is lost from the seed. If stored poorly or overstored, the seed becomes numb and is then no longer capable of germination. On the other hand, under favorable storage conditions, germination can last for several years. The seed must be deprived of light, air, water and nutrients during this time. Various factors play a role in this:
- no temperature fluctuations
- temperatures around 10 °C or below
- summerhouses and attics are not suitable in summer
- dry room air necessary
- humidity accelerates the formation of molds
- airtight container (e.g. disposable jars with lids)
- container must be mouse-proof
- use silicon gel (drugstore) to reduce humidity
- store in the dark
- if necessary, store the container in paper bags or boxes
- in summer do not store in plastic containers
- support condensation and rotting
- storage in frost is not a problem
- no loss of germination capacity
- in winter storage in garden shed or summer house possible
During storage, the lawn seed should have little to no contact with air and moisture, the longer it will keep. If the storage place is a cellar, it must be dry. In most cellars, appropriate humidity can be found. It is also possible to freeze the seed at -18°C for several years. For this, the seed must be well cleaned and dry, so that no damage occurs. Silicon gel can be used for drying. Afterwards, the seeds have to be filled into metal-coated bags and sealed under vacuum. However, this method is quite laborious.
Tip: Special seed boxes for seed storage are available in stores. These offer protection against moisture and temperature fluctuations. Continuous air circulation prevents rotting or premature germination of the seeds. The boxes are made of metal and thus also protect against rodents and insects.
Make germination test
To determine the germination capacity of older grass seeds, a germination test should be made before use. Sometimes it is enough to simply look at the seeds to see if the seed has been damaged during storage. When opening the package or storage container, make sure that
- the contents are dry and unchanged
- the smell is fresh
- the seeds are still firm, dry and pointed
If, on the other hand, the grass seed has already germinated, has a musty and musty odor, and is also moist and soft, and perhaps there are already traces of mold, it can be assumed that there is no longer sufficient germination capacity. The germination rate will be very low, which will be reflected in an extremely thin lawn cover and bare patches. You should no longer use this seed and dispose of it. It is therefore always advisable to carry out the germination test on older lawn seeds:
- lay out a flat tray with dampened kitchen paper
- spread some seeds on it and moisten them
- Cover the tray with foil
- place in a dark place or cover with a cloth
- ideal warm windowsill
- for germination soil temperature of at least 12 °C necessary
- keep seed moist
- after about 8 to 20 days seedlings should appear
Optimal would be the germination of half of the seeds. However, the result can be different, for example
- no seedlings – seed is numb, no use anymore
- few seedlings – use still possible, simply sow more densely
- germination of half or all seeds – normal sowing possible
Tip: Cheap offers of lawn seeds, for example at discounters, are usually of low quality and durability and also the germination capacity is sometimes much worse.
As already mentioned, the germination rate decreases with a longer storage period. Therefore, you should apply a higher quantity when sowing to compensate for the lack of germination. Of course, there may still be failures or poor germination. However, this does not always have to be due to the age and shelf life of the lawn seed, but may simply be due to poor germination conditions such as
- poorly prepared soil or
- unfavorable weather conditions
If you now want to use older seeds, you should create appropriate conditions for good germination, for example
- sufficient light and water
- shady places have different requirements than fully sunny places
- avoid waterlogging
- add sand or drainage if necessary
- prepare the soil well, free of weeds
- crumbly soil structure
- for older seeds high nutrient content of the soil is important
- fertilize if necessary
After sowing older seeds, apply a thin layer of soil and then lightly roll it. This gives the seeds good contact with the soil, as well as promoting the absorption of nutrients and preventing them from being washed out during heavy rainfall. The seed now needs sufficient watering, but you must not silt the soil.
Tip: The crumb size of the top layer of soil should be about two centimeters, then a good soil contact is guaranteed. As a rule of thumb, everything that fits through the tines of the rake can remain on the surface of the bed.
I have 30 years of experience and i started this website to see if i could try and share my knowledge to help you.
With a degree a Horticulture BSc (Hons)
I have worked as a horticulture specialist lead gardener, garden landscaper, and of course i am a hobby gardener at home in my own garden.
Please if you have any questions leave them on the article and i will get back to you personally.