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Seed Propagation

Stratification

Overview:

Collecting seed is an inexpensive method of producing plants, but it must be said from the outset that results can be somewhat indifferent.

For example, plants grown from seed will not always come true to the parent plant, however, it is this attribute that often gives one the satisfaction and pleasure of producing a plants that is quite unique.

It would also be true to say that quite often results can be a complete failure or the plants produced, are inferior to the parent plant.

There are a number of factors that can contribute to this, not least, the viability of the seed used.

A simple rule to keep in mind is: Seeds need to be fertilised, mature and ripe before collecting.

That is, if they haven't been fertilised, they won't mature, if they havent matured, they won't ripen, and finally; if they have not ripened they are unlikely to be viable.

As with many processes, there are a number of rules and procedures that should be followed to achieve success, collecting seed is no different, and a knowledge of seed types can be of help as some types succeed better than others.

Seed Types:

Open-Pollinated Seeds:

These are seeds that are left to the bees and other natural pollinators to pollinate.

Seeds saved from open-pollinated plants will give more or less the same mixture of colours, sizes or heights as the original plants.

F1 Hybrids:

Hybrids are plants with mixed parentage.

These are seeds of two particular plants that growers / seed-merchants have cross-pollinated.

These are first generation plants, and can only be produced by crossing the two particular parent plants again.

They are pollinated manually in areas where there is no possibility of cross fertilisation.

The plants are crossed with with another plant that has certain attributes that is desired in the other.

For example, a non-vigourous variety with a desired colour may be crossed with a plant that is a more vigorous grower, in the hope of attaining a vigourous variety of the desired colour.

Similarly, crossing can take place to emphasise colour, height, size and number of flowers and fruit.

Seed saved from F1 plants that have been open-pollinated will not as a rule produce plants similar to the parent.

When to Collect Seeds?

As mentioned above, seeds should be fertilised, mature and ripe before collecting.

This can often raise the question: When are the seeds ripe?

Let nature tell you when, wait until you see that the plant/s are about to disperse them naturally and collect them then.

The Signs:

Often the seed pod will become dry and change colour from perhaps green to brown or off-white.

The seeds within the pod will also often change colour and feel quite hard and relatively dry.

A good example that most people are familar with is an Apple.

Firstly the unripe seeds are soft and green, then the colour changes to a shiny brown and the seed becomes quite hard when the Apple ripens.

Tools required:

Prior to collecting seeds it is advisable that you have a container at hand with some essential tools in it, for example:

• A few fairly large paper bags to place the collected seed pods in and a marker pen to label the contents.


• Small scissors and or a knife to cut the pods from the plant/s,they may also be needed to open the seed pods.


• Various bits and pieces to extract seeds from the pod e.g.lollipop sticks, tweezers, two laths for pressing soft fruit, and a small hammer/mallet to crack hard seed pods to name but a few.


• Several sizes of sieves or strainers.



For example: one with say largish holes in it to retain the heaviest of the chaff, a second to retain largish seeds, and one with a smaller mesh that lets small seed through, and finally a nylon mesh seive to let dust sized seed through.

• Sheets of paper or paper trays to dry the seeds on prior to packaging.


• The best form of packaging is paper envelopes or old seed packets, alternatively make you own. (see template below)


• Plastic bags/envelopes should should be avoided as these can sometimes sweat and the condensation within can rot the seeds.


• Finally a large air tight container to keep all the packages in until required for sowing, an air tight biscuit tin is ideal.

Collecting the Seeds:

Always harvest seeds when the weather is dry.

Similarly try not to collect them when the seed pods are damp.

If this can not be avoided then lay them out separately on newspaper to dry.

Extracting the Seeds:

Large seeds such as beans can be removed by hand by simply picking them out of the pod with your fingers and laying out to dry.

Slightly smaller seeds may be extracted with tweezers.

Where seeds are contained within a hip (roses) cut open with a knife and scrape the seed out with a spatula or something similar.

Be careful with rose hip seeds as they can cause a skin irratation, and are sometimes used as a form of itching powder!

Using your fingers will be fine in some situations, but messy in others e.g. when de-seeding soft fruit.

Seeds in dried pods should be placed in a paper bag and vigorously shaken to extract the seed from the pods.

The contents of the bag are then seived to remove the seeds from the chaff.

Fleshy outer coats of berries can be removed by carefully pressing the berries between two pieces of flat wood, the resulting flesh is then scraped onto a piece of paper kitchen towel to dry, prior to packaging.

Seed that are contained in a gel e.g. Tomatoes, should be firstly placed into a cup of clean water and vigorously stirred to seperate the seeds from the gel.

Strain the resulting mixture through a seive then place the seed on a piece of kitchen towel, paper plate or piece of glass to dry.

These seeds can be quite sticky and when dry they tend to stick to the paper/paper plate making them difficult to seperate.

Using a small sheet of glass or plastic makes for easier removal once dried.

Storing seed:

After separating the seed,ensure that they are absolutely dry before storing them.

Damp seed will rot!

Leave the seed for a couple of days in a dry environment, then pack it into paper envelopes.

Always remember to label the envelopes clearly.

Place them in an air tight box / tin

Keep the seeds cool, dark and dry place until required.

Stratifying:

Some types of seed will need to be stratified before they will germinate in the spring.

This is done by subjecting them to a cold spell, i.e. replicating what would happen to them when subjected to frost in the open.

To stratify seed, place dry seed directly into paper packets, e.g. old seed packets or home made ones.

Place the packets in a refrigerator, not the freezer for six to eight weeks then sow as normal.

Alternatively the seeds can then be thickly sown in a 25mm (1”) layer of silver sand on top of a large pot or pan of seed compost and placed outdoors.

Cover the container as protection from mice and overhead drips, but never allow the sand to become dry.

Ensure seeds are clearly labelled.

In late winter or early spring carefully remove seeds and silver sand from the container and sow in the normal fashion.

Germinate in a cold frame or greenhouse.

Seed Packets:

Click template to enlarge, then copy and paste it on to suitable paper and print off as required.

Cut out the printed templates and fold and paste to form the seed envelopes.

The more adventurous among you who want a professional look to their packets, can add text and / or pictures to the templates prior to printing.