FOLLOWING the published results of a series of tests carried by Garden Which? since February 2009 I felt that it might be useful for readers to have an insight into some of the more interesting results and the implications for amateur gardeners.

Runner bean, spring onion and cucumber seeds were purchased by five mystery shoppers from 17 leading suppliers and begonia and pelargonium seeds were bought from 13 companies.

These seeds were tested by a seed-testing laboratory that is accredited by the International Seed Testing Association (www.seedtest.org).

The seeds are given the optimum temperature and light to maximise germination and any failed seeds are checked to see if they are alive and viable, dead or immature.

The results should meet specific germination percentages for any one type. This exacting process is designed to ensure that when you buy an expensive packet of seed you will get the best results providing you give the seeds the optimum conditions.

Of course if you save your own seed the results are of no concern to anyone else.

But issues such as time spent in storage, temperature and humidity in storage, quality of seeds harvested and freedom from pests and diseases – let alone trueness to type – are all issues that you will need to consider, as the seed companies do.

It is among these issues that things can go wrong.

Out of all the companies tested, Dobies (www.dobies.co.uk) came out best with 88% of seeds germinated with good instructions on the packets and a user-friendly website to help potential buyers.

Nicky’s Nursery (www.nickys-nursery.co.uk) achieved 83% germination although the growing instructions on the packets were not always good.

Suttons (www.suttons-seeds.co.uk) achieved the same percentage but had the best growing instructions overall.

Sadly for Unwins (www.unwinsdirect.co.uk) their seeds only achieved 58% overall. Most of the other seed companies achieved between 67% and 75% germination.

But these trials show us that, no matter how pretty the packaging and the advertising, there does not seem to be a 100% guarantee that all the seeds you sow will turn into new plants.

Which is why, over recent years, gardeners have been buying plug plants through the post or buying young plants at the garden centres, leaving the risky business of germination to the commercial growers.

The only problem with this technique is that you only have the choice of varieties that they grow for you whereas the seed catalogues offer a much wider range.

Follow these simple rules to help improve the germination percentages of your seeds whether purchased from a reputable company or saved from your own or someone else’s garden:

1. Store seeds in a cool, dry, dark place, with a small packet of silica gel to soak up excess humidity – an old sweet or biscuit tin is a good container to use. Do not store in garden sheds as their temperatures can fluctuate dramatically, even in winter. Never store dry seeds in plastic bags.

2. Always use the freshest seeds – germination percentages drop rapidly as each year passes. Check dates on the back of seed packets, particularly if you are buying out of season or at reduced cost.

3. Buy a soil thermometer to check soil and compost temperature before sowing – temper bags of compost to the room or glasshouse temperature for at least two days before using.

4. Specific techniques may be required for some plants so do some good research beforehand and follow instructions to the letter. Issues such freshness, light and dark germination, chilling, soaking and chitting all influence the germination of seeds. Treat yourself to a copy of Karen Platt’s Seed Sowing and Growing Success book – www.karenplatt.co.uk , ISBN 0 9545764 0 3 for some really detailed help on how to germinate even the most difficult seeds.

5. Maturity and viability often go hand-in-hand with seeds and it is essential, if you are home harvesting, to be patient and not harvest too early and to dry the seeds thoroughly before putting them into storage, assuming that seed does not need sowing immediately.

Good luck with your seed catalogue searching this autumn and winter – let me know your experiences with bought and home harvested seeds – write to me at Graham’s Seeds, Features Office, Huddersfield Daily Examiner, Queen Street South, Huddersfield, HD4 3DU.