Sowing success – Why seed quality matters

How do you really know whether the seed you are spreading to your lawn is any good? Will it germinate? Will it be true to type? And will it be weed free?

Grass seed quality matters because it can greatly impact the success of your sowing efforts. Quality grass seed has a higher germination rate, meaning that more of the seeds will sprout and grow into healthy grass. On the other hand, low-quality grass seed may have a lower germination rate, resulting in patchy, thin areas or even bare spots.


  1. Purity: high-quality grass seed should be free of weed seeds, other crop seeds, and other debris. If the grass seed is impure, it may lead to unwanted plants growing in your lawn, which can be difficult to remove.
  2. Germination rate: the germination rate refers to the percentage of seeds that will sprout and grow into healthy grass. High-quality grass seed will have a higher germination rate, which means you’ll get more grass from fewer seeds.
  3. Moisture content: grass seed with a high moisture content can spoil or rot before it has a chance to germinate. Low-quality grass seed may have a high moisture content, which can lead to poor germination rates.
  4. Genetic purity: grass seed should be genetically pure, meaning that it should be the same variety and not contaminated with other varieties. This ensures that you get the desired characteristics of the grass you’re planting.


The majority of lawn seeds available in New Zealand undergoes a rigorous international seed certification program. This allows buyers to determine germination percentage, number and type of weed seeds, the amount of foreign material such as chaff or straw and that it is true to cultivar.

The seed that has been tested and meets the appropriate criteria has a blue tag stitched into the bag. If that bag is then re-opened to be blended with alternative seeds, it no longer qualifies as certified seed.

Typically, the highest quality seed grown in NZ is exported. Furthermore, all the seed still gets sold, regardless of its weed content or its tested germination rate.

Much of the lower grade seed get covered with pretty coloured coatings that are described as being “bird repellents”, “fertilisers” and/or “fungicides”. These are normally available as domestic packs often sold in bulk stores as lawn seed for residential homes.

Interestingly, international scientific research has for a long time proven that these treatments will decrease the germination percentage. Secondly, much of the weight of the seed being purchased is comprised of these coatings. This implies that for each kilo of coated seed being purchased, the homeowner is actually receiving less than 50% of the weight in actual seed!


Investing in high-quality grass seed can greatly increase the chances of success when sowing. We recommend that our customers do thorough research before choosing a seed supplier, to ensure they’re getting pure, unblended, certified, sod quality seed.

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