Wednesday 18 July 2018

Sow the seeds of success

That tiny seed carries all the fuel it needs to grow into a plant, writes Gerry Daly

Knowing a seeds’ needs helps germination
Knowing a seeds’ needs helps germination

Spring is the main sowing time of year for the very good reason that seeds have a full season of growth ahead of them and the best chance for the seedlings to get well-established and grow rapidly.

Plants native to temperate parts of the world largely stay dormant in winter and germinate when the weather warms up, though these last few weeks haven't felt any warmer. In tropical countries, the conditions are much the same all year round and seeds of tropical plants can germinate at any time of year, if moisture is available.

A seed is a little packet of food and carries the bud of a tiny seedling. The food resource can be sugar, starch or oil and this fuels the rapid early growth of the young seedling, ensuring it gets its roots into the soil and its seed-leaves are expanded to receive the life-sustaining sunlight. Once the seed is rooted, it can draw up its own moisture and the young plant is away.

For germination to take place, the seed needs a supply of moisture and air. The seed soaks up moisture and swells. Enzymes break down the food content into simple sugars to fuel growth. For the plant to use the growing sugars, oxygen in the air is needed. Seeds can rest, without germinating, for decades, even centuries, a few centimetres under the soil. This is a form of dormancy because seedlings would find it very difficult to push their way up through a few centimetres of soil.

To avoid germination at the wrong time of year, or at the wrong depth, some seeds have natural dormancy, a hard water-proof seed coat or a chemical that only breaks down after a period of cold, for instance holly and mountain ash. Some seeds need smoke to indicate the ground layer has been wiped out and it is good to germinate without competition from other plants. Knowing what plants need naturally for germination helps success in the garden too.

With needs for warmth, moisture and air, success in raising plants from seeds depends on supplying the seeds' needs in the right amount. The warmth of the sun is often enough as it heats the soil but plants from warmer countries might need the extra push of a heated propagator or heat mat.

Choose a good seed compost that is open enough to allow air in, holds the right amount of water, but is fine enough to allow seeds to push up. A thin layer of vermiculite is very light and allows light to reach the species that need light, such as lettuce. Some seeds are very difficult to sprout but most are very easy.

In theory, every plant produces seeds - or spores in the case of ferns - and wild plants generally do. Most garden plants can be raised from seed but some have become sterile as a result of cross-breeding and some do not come true to their variety.

Trees, shrubs, perennial flowers, annuals and vegetables are raised by seed. There is immense satisfaction to be got from a 10m tree that you raised from seed. And there is great pleasure to be had in sitting down to eat food raised from seed sown by your own hand.

Visit a showstopper

Coolcarrigan House, Co Kildare, will be open from February 22 to March 2 for snowdrop viewing and later a fine crocus lawn and daffodils. Victorian garden, rockeries, lily pond, herbaceous borders, lawns, greenhouses and impressive collection of shrubs and trees; coolcarrigan.ie

Stay sharp

The 1000/3000 combination stone is all you'll ever need to keep the cutting edge on your garden tools. Use 1000 for regular sharpening, then the 3000 for finishing. From Niwaki, €40.32; available at Howbert and Mays stores.

Grow a little wonder

The Coronet miniature apple tree has been a bestseller for 20 years. Coronet trees crop immediately, remain miniature permanently and are easy to grow with no pruning needed. They are available in all good garden centres. Plant now. See coronet.ie for more information.

Sunday Independent

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