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Seed advice

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Jim McColl Jim McColl | 12:30 UK time, Tuesday, 11 January 2011


Can I use seed that I didn't need in 2010? That question is often asked and the answer is always the same and it starts with the words 'it all depends'. Most vegetable seeds will keep for a few years with parsnip being the dodgy one. Herb seeds are short lived and quite a few flower seeds remain viable for just a year or maybe two. You will readily find the appropriate seed longevity charts on the Internet.

The second point to consider relates to storage. Most seeds nowadays are packaged in hermetically sealed foil sachets. After sowing, the remaining seeds can be returned to the foil envelope. Folding over the open end a couple of times should achieve a decent seal. If these packs are stored in a cool place where the temperature is likely to be constant, they will remain viable for quite some time. Finally as time goes by the viability of the seeds will start to diminish therefore you must be prepared to sow a little more thickly than is recommended, to finish up with your requisite number of plants.

From time to time Garden - Which? has published results of germination tests carried out on new seed which have shown pretty awful results. The attendant publicity would be sufficient penalty for the businesses concerned! The reason I mention this relates to the seed count in each packet and what you have to pay. Spend a little time studying the information provided, particularly the seed count.

That brings me neatly to the question of whether or not to use F1 hybrids. As you will be aware these particular cultivars are given this appellation because they are the First filial generation of a cross between two pure, self-breeding lines. The resultant seeds are expensive because the plant breeder has to maintain the male and female lines pure and separate to achieve the desired effect. What effect is that? There are several, firstly there is what is known as hybrid vigour, which is self-explanatory. With that come a number of attributes - stunning flower colours, enhanced perfume, resistance to bad weather conditions, uniformity of form, disease resistance, heavier cropping. For amateur gardeners, I suggest the F1 flowers are definitely worth growing but when it comes to vegetables, there is one snag: that uniformity which is so effective in producing a floral display is not so welcome when you plant 24 F1cauliflowers and there are 24 heads ready to be harvested on the same day! I exaggerate slightly but I tell you they can be pretty close. That said, the F1 hybrid Brussels sprouts can be absolutely marvellous, so long as you pick little and often. Favourite amongst the early introductions was Peer Gynt which I have picked from November through to March. It has undoubtedly been superseded by others as good as or even better.

Earlier, I mentioned disease resistance as one of the benefits of using F1 hybrids, staying with brassicas, there is now a range of clubroot resistant varieties. If your ground is infested look for cabbage Kilaxy or Kilaton; cauliflower Clapton; and for sprouts Crispus. All are substantially resistant to the disease.

What about collecting and storing seeds from plants in your own garden? Some things with large seeds like broad beans for example; you simply leave the pods on the plant for as long as possible, pick off and separate the beans and allow to dry. The simplest way to harvest many small seeds is to cut the flower stem as in dead-heading and drop the lot into a bag. By so doing, you are less likely to loose the seeds that have already ripened. For convenience, the first inclination is to use a polybag and I have no problem with that so long as you do not store the seeds in such a container. Take the harvested stems with seed heads facing downwards in the polybags to the garage or shed and hang them up to allow the ripening process to continue. Don't seal the neck of the bag tightly. Remember to LABEL the contents.

With the passage of time, the ripened seeds will tend to drop from the heads into the bottom of the bags, some may need a bit of encouragement by shaking or gentle rubbing. Traditionally, we would then transfer the ripe seeds to a brown paper bag or envelope (with label). Several may then be stored in an airtight jar until spring.

Earlier I mentioned F1 hybrid seeds, home saved seeds are said to be 'open-pollinated', in other words there has been no control of where the pollen has come from! As a result, the new plants are unlikely to be true to type. They are likely to be a mixture with good, bad and a whole raft of stages in between. That, for some people, is the excitement, indeed that is how many new kinds are discovered and developed.

Jim McColl presents BBC Scotland's the Beechgrove Garden.


  • Comment number 1.

    There is a new word in the system 'Landrace', which means the saving and exchange of vegetable seeds that have adapted to the local soil and climate.

    I save Broad Bean 'Aquadulce', care with beetroot which can cross with perpetual spinach and result in poor shaped, pink, bland roots.

    However F1 varieties are good, so I keep a foot in both camps.

  • Comment number 2.

    I'm a bit new to this, so apologies if this is a silly question: If I understand correctly, tomato flowers will easily pollinate from other flowers on the same plant, and tomatoes suffer no loss of vigour over generations; so why do we need to buy F1 seeds each year? I've also heard that second-generation plants will revert to one of the parent plant types, but this doesn't really fit in with my (school level) understanding of biology. Is it something that is routinely tested?

  • Comment number 3.

    @ hereisabee....I am interested to know about the 'Landrace' designation for seeds of local provenance, thank you. I thought the word only related to a breed of pigs!

    Broad bean 'Aquadulce' would be one of these true breeding lines I was on about.

    The beetroot/spinach experience just illustrates what happens when open pollination occurs. You don't always get the answer you are looking for which is great fun if you can afford the time and space.

    Leaving best till last - a foot in both camps, I like that.

    @ Mathizo....
    The tomato is self fertile that is true. Suffering no loss of vigour over many generations is a moot point but hey, you don't have to use F1s.

    The fact they will produce heavier crops of flavoursome fruits and be less prone to disease need not be taken in to account!

    Talking flavour, please don't base your opinions about F1 tomatoes on supermarket-bought fruit, try home grown F1s I could go on a bit on this one by referring to plant shape. For example, the old stagers like Moneymaker and Ailsa Craig are classed as being tall spreading in habit with a tendency for the stem to stretch between trusses whereas most of the F1 regular varieties, like Shirley for example, are described as being intermediate in habit and therefore easier to accommodate in a small glasshouse where headroom is limitied.

    To the point about the second filial generation or F2s - have you tried them? The best I could say is that, in my experience they are interesting but I wouldn't grow them again!

    I could not go into the genetics in depth because I would undoubtedly get stranded up the creek but, having planted F1s, when they flower and become open pollinted, the control that was in place when the F1 was created, has been lost, the issue when grown the following year will exhibit a whole gamut of characteristics which were in the genes all the time but not in the same order of dominance and recessiveness to which must be added the pollen of the same genus brought in from 'oot aboot' as they would say in these parts. In other words from other gardens in the neighbourhood.


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