What’s So Good About Seeds?
Growing from seed can be both cost-effective and very rewarding.
Before growing from seed, it is worth finding out about what a seed is and how it germinates.
Some tropical plants can be grown from seed as well as fruit, vegetables and many others.
Seeds are packets of genetic information stored with a food supply within a protective casing. They contain everything that is needed to turn a tiny seed into a huge tree, with a bit of help from nature. Seeds are by far the most common way that plants reproduce in nature.
They are usually produced as a result of fertilisation by 2 non-identical members of the same species. Seeds can be fertilised by insects, birds, animals or wind pollination, to name but a few methods.
When the parents’ genetics combine, they are not combined in a ratio of exactly 50/50. In fact, the parents’ traits are passed to the offspring in varying proportions, creating variations within the offspring.
Variation in Genetics
These variations cause the offspring to be taller or shorter, larger-flowered or smaller-flowered etc. Essentially, the variations make offspring more or less suited to the environment it finds itself in. The better fitting offspring will go on to grow strongly, whilst the weaker ones may struggle or even die, making them less likely to reproduce, and thus ensuring the progression of the stronger gene pool.
As an example, if you pair up a very tall, lanky specimen of a particular plant with a short one, you are likely to obtain seed and offspring of many varying heights, some short and some tall. Depending on the environment, some of the offspring will be better suited to the environment than others, and will therefore grow stronger and faster.
This variation is the foundation of natural selection, with these variations producing slightly different offspring that will compete with each other, and other species. The stronger, fitter specimens will go on to reproduce and ensure the species therefore continues with the strongest, best-fitting gene pool possible. Evolution is a fascinating subject and is the reason everything is as it is today, and will be tomorrow.
Generally, seed should be collected from a plant as soon as it is ripe. Usually it is best to store seeds in a dry, dark place at fridge temperatures (about 5 degrees celcius) but it is important to understand that different seeds may need different treatment.
Some seeds need to be planted immediately to ensure viability, where some will store for many years without being adversely affected. Many species do best following a period of stratification, which is a controlled period of cold, or warmth depending on the species.
Many fruits need cold stratification for a few weeks up to a couple of years to aid germination.
Cold stratification effectively mimics the winter period and triggers germination. Some seeds are pre-programmed to germinate only once it has gone from cool to warm, such as in Spring. Cold stratification promotes strong germination and can be manipulated to fool some seeds into germinating when you want them to.
Some seeds have extremely hard casings and as such it is very difficult for a developing embryo to penetrate the case and begin its journey through life.
Hard cased seeds have developed to be hard for a reason. For example, it could be to ensure that the embryo does not emerge until the seed has been soaked in water for a long period (and therefore the case softened). If it is wet enough for long enough, the case will soften and water will penetrate into the seed. This triggers the embryo into growth. As the case is nice and soft, the embryo’s growing tip can penetrate the case and the plant can grow! Effectively the seed now ‘knows’ that when it emerges, there will be plenty of water for it.
There are various ways that you can help your seed break through the hard case. The process is know as ‘Scarification’ and involves either carefully ‘nicking’ the seed coat with a knife, or using sandpaper or another abrasive to gently wear away the seed case, making it easier to germinate. This may sound quite brutal, but it is effective and just speeds up nature’s mechanism.
This also applies to many seeds that are dispersed by birds and animals. Often, fruit seeds are covered in a tough layer, such as wax, that prevents them from germinating. In nature, the tough layer would be eroded by the digestion system of the bird or other animal that has eaten it. The resulting droppings contain a nicely prepared seed that has got a good chance of growing, especially as it has been deposited with its own stock of manure!
Seeds need Air, Water and Warmth to germinate. Some also need Light where others need Dark.
So, to give yourself the best chance of producing new plants, you will have to give some thought to the individual needs of each seed. However, the following guidelines should give you the basics.
1. Check your seeds are healthy. Ideally, they will be fairly uniform in size and colour and show no signs of disease. Many seeds have a ‘Sow By’ date. Whilst passing this date does not mean your seeds are all dead, it is best to sow them before the deadline to ensure maximum viability.
2. Use specialist sowing compost in seed trays or small pots. Sowing compost contains less than a third of the fertiliser in other composts and has a structure that will assist good water distribution as well as allowing air in to the soil. I always add Perlite or similar to ensure that the soil is well-draining and fairly light.
Remember that the seed contains all the food needed for germination, so don’t apply any fertiliser yet!!
If the soil is too light, with lots of air-spaces, water will not be evenly distributed in the soil and as such some seeds may perish. Conversely, if the soil is too compact it will easily become waterlogged and this can easily lead to rot. Many sowing composts have fungicide added, which helps prevent ‘Damping Off’ Damping off is an indicator of over-watering, overcrowding, lack of drainage or air. Paying a bit of attention to the conditions should avoid any fungal problems though.
3. Keep the temperature at around 20 degrees celcius and keep a close eye on your developing seeds. A heated propagater will do a perfect job, but there are many different options here. I use as much recycled material as possible – whether this be homemade greenhouses from plastic bottles or drip trays from plastic packaging from the Supermarket. You should never buy a small pot- you can Recycle household items or get them for free from your local Garden Centre, or use any of the millions of plastic items we throw away every year.
With a bit of luck, you will soon see shoots appearing – What Happens Now?
Once your seeds have successfully germinated they will need a bit more care from you. Of course, if you have sown your seed directly in its final position, you can just watch it grow. However, if you have sown individual seeds in pots or groups of seeds in trays, you are about to get busy!
Pricking Out is simply the process of carefully transplanting your seedlings into a larger home. Thinning out is a similar process, but the resulting thins are not necessarily kept.
When your seedlings have emerged and are large enough to handle, it is time to move them on.
Pricking out is the process of carefully removing the seedling and putting it into its new home. I use a plant label or similar to gently tease below the seedlings roots. When I have got under the roots, I carefully grip the leaves and gently ease the seedling out, using the plant label to double-support it. I then move it into a pre-prepared hole in a new pot before watering in, labelling and putting in place.
Always keep an eye on newly transplanted seedlings as they are delicate and will still need optimum warmth, water and air conditions to progress.
When the plant has grown on and is easy to handle, say at about 3-4 inches tall, it will be ready to begin the hardening off process, if it is going to live outside.
Plant out when you have hardened off your plant. Hardening off is simply the process of acclimatising your seedling to outdoor conditions. It has been carefully nurtured in ideal conditions up to now, so just putting it outside in cool weather may not do it any help at all.
Most plants must not go anywhere near the outside until after the frosts have passed. At this time, plants can be placed outside in a sheltered spot during milder days for a few hours. Extend the period by an hour or two every few days until your plant is fully accustomed to the cooler conditions. Plants are all different and will need appropriately longer or shorter hardening off periods. Keep an eye out for sudden frosts!!!
Growing On Your Plants
This is the bit you have been waiting for – after all your hard work you can now admire your new plant as it grows. Take care of your plant and it will reward you with lush foliage and beautiful flowers.