How Seed Quality Determines Vegetable Growth Success

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As you may have already discovered, seeds from different suppliers can look very similar, but the quality - and how well they germinate and grow - can vary a lot. Some seeds will grow into strong, vigorous plants and some will not. Some may not even germinate well. So it's really worth starting with the best seeds you can get.

This post will help you understand a bit more about why some seeds perform better than others. And offers tips on how to find good quality seeds.  

Why Look for Good Quality Seeds?

Seeds hold all the genetic information plants need to grow into strong, healthy plants. Watching tiny seeds emerge and grow into beautiful plants is one of the miracles of gardening. Fresh, good quality seeds will offer several benefits, including:

  • Higher germination rates, meaning more seeds sprout successfully.
  • Stronger seedlings, which are more likely to thrive and resist pests and diseases.
  • Often higher yields.
  • More likely to be 'true to type'. In other words, more likely to exhibit the features described for the particular variety. (For example, poorly bred plants may start to lose their flavour or be more prone to diseases). 

This means that it's always worth starting with the best seeds you can get. 

What makes some seeds better than others?  

The quality of seeds - and how well they grow in your containers - depends on several factors, including: 

  1. Healthy seeds can only be saved from strong healthy plants, grown in good conditions and by someone with appropriate seed saving skills.  Where and how seeds are grown is usually invisible to us when we buy them. This means we need to rely on a trusted seed seller to source high quality seeds for us. 
  2. Where the seed is grown. Seeds that have been saved from plants grown in a similar climate and conditions to where you grow will become better adapted to local conditions. In the UK, most large seed suppliers import their seeds, often from thousands of miles away (this doesn't mean they are bad, just not optimal). 
  3. How old they are. The viability and vigour of all seeds diminishes over time. Some seeds last longer than others. For example, tomato seeds can remain viable for 3 to 7 years (I've successfully grown some 10 years old), while onions last only 1 to 2 years and peas 2 to 4 years (I find pea germination declines rapidly with age). You can find full lists of how long different seeds last on line, for example Joe the Gardener has a downloadable PDF list here. Do check this before sowing seeds from old packs in the cupboard! Note: many seed packs (in the UK at least) only list the year end packing date and not the date the seeds were first collected! This is not very helpful as it doesn’t tell you how old the seeds are...
  4. Storage. How and where they have been stored - they keep best in cool, dark, dry and stable conditions, and deteriorate more quickly if it is warm or slightly damp. 

Tips for procuring your seeds:

  • Look for small seed suppliers who cater for the home gardener - as they will often sell varieties and pack sizes catering more to our needs. Also look for those who save or procure seed grown in the country you live (most of the larger seed companies import seeds over long distances). Good examples in the UK include Real Seeds and Vital Seeds.
  • Or try to find seed companies that specialise in supplying seeds to small scale professional growers as they tend to offer more reliable seed quality. In the UK, examples include Tamar Organics and Moles Seeds. 
  • Look out for local seed swaps. These often happen in the spring. A list of some swaps in the UK is published by Garden Organic here. However, local swaps are not always well advertised so you may need to ask around or do some more research to find one near you. 

Finding Seeds on a Budget

The cost of seeds can quickly add up, particularly when postage is added in. If budget is an issue:

  • Look for seed swaps, organise your own seed swap, or try sharing seeds informally with others.
  • Join a community gardening group - often someone has a surplus of seeds they are happy to share. 
  • Look on Ebay for low cost seeds - just be aware that quality can be variable... That said, I've normally found them OK...
  • Learn to save your own seeds. Some seeds - like pea and tomato - are easy to save each year. 
  • Be wary about seeds in budget supermarkets - they are sometimes OK but quality tends to be more variable. 

Key Points to Remember

There is a fair bit of information here but it doesn't need to be overcomplicated. The three most important things to remember are: 

  1. The quality of seeds does make a difference so it's worth trying to find a reliable supplier of good quality... but, if necessary, even Ebay seeds will often grow OK! 
  2. Seeds do deteriorate with age (and if not stored well), some faster than others.  Fresh seeds will normally grow better - but do use up your old ones if they have been stored in cool, dry conditions and are within expected age range for viability. If unsure, test a few first. 
  3. If seeds are not germinating well or growing with good vigour, remember that it might be down to poor quality seeds (watering, temperature and the quality of the potting mix are other possible factors). 

Your Turn

Have you had any bad experiences with seed you can share for us to learn from? Or discovered good seed suppliers in your country that save their own seed or procure seed locally? Do share them in the comments. 

I hope you will have fun choosing and finding seeds for the coming season. It's an exciting time!


Margaret Clarke

Thank you so much Mark - I just want to second your recommendation for great seeds. I bought from Real Seeds last year and they were head and shoulders (in the case of the beans - LITERALLY!!) above previous seeds!

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Mark Ridsdill Smith

Oh, so pleased to hear you had a  great experience with Real Seeds, too. Love the way the provide seed saving instructions as well. 

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Hi  Mark,

Have used Real Seeds (Newport ,Pembs  ) for some years now - Excellent germination, good advice and  value for money ! Stay warm and dry.

Cheers  Glyn

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Hi Mark,

Just to endorse your use of Real Seeds, have used them for some years now. Give excellent germination,planting advice and value for money! 

Stay warm and dry.

Cheers Glyn

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