How to Propagate Plants Yourself

There are many reasons for propagating plants yourself. True, you can always buy young plants from nurseries and garden centres, and these may have the advantage of developing and flowering more quickly. But it is more exciting to grow your favourite plants yourself. A further bonus is that propagation from seed, cuttings or division is considerably less expensive than buying plants. If you have large areas to cover this is an important consideration. Finally, it is a fact that some exotic plants, herbs and vegetables are only available as seed, so propagating them yourself is the only way to grow these plants.

You can harvest your own seeds from a large number of plants very easily. Pick the ripe seed pods, put them in a bowl or box and leave them to dry for a few days in a well-ventilated place.

As soon as the pods have dried out, gently shake the seeds out of the pods and store them in screw-top glass jars or paper bags until the following spring. Remember to label the containers!

Generative propagation

This term refers to the propagation of plants from seed. Balcony gardeners with little space available for propagation trays should restrict themselves to plants that develop quickly from seedling to the (lowering stage. This is the case with many summer-flowering annuals, climbers, herbs and vegetables, and even for some herbaceous perennials and grasses.

On the other hand, biennials such as daisies or pansies take much longer by definition: sown in summer, they form a leaf rosette in the first year and only flower the following spring or summer.

Seeds: When buying seeds check the sell-by date and make sure that the sealed packaging has not been damaged. Avoid faded seed packets, since this is an unmistakable sign that it they been left too long in the sun and the seeds’ ability to germinate may already have diminished. Seeds should always be stored in dry, well-ventilated conditions so as not to reduce their germination potential.

Calibrated seeds have been graded according to size, while coated or pelleted seeds have been coated with a protective covering that also makes them easier to handle because they are larger. Vegetable, herb and flower-seeds are also frequently sold in the form of seed tape, which automatically places the seeds the correct planting distance from each other.

Seedlings raised from seeds you have harvested yourself will vary to a greater or lesser degree. They can surprise you every year with their variety, while bought seed from F1-hybrids produce plants that are very true to type.

The explanation for this phenomenon is as follows. In the case of F1-hybrids, these are the first generation of a crossing between two homozygous parent plants whose positive properties are combined. But their descendants do not remain uniform, which means that for consistency you must buy seeds every year.

Germination containers: You can use ordinary plastic bowls, polystyrene boxes or clay or plastic flower-pots. Nurseries and garden centres sell seed trays with transparent covers as well as heated mini-greenhouses with temperature control for more exotic plants. Multi-pot flats have the advantage that the seedlings quickly develop a firm root ball. Pots made from compressed peat, which swells up when watered, can be planted as they are with the seedlings inside them; they are of course also biologically degradable.

Compost: Compost used for propagation must not be too rich in nutrients because these would ‘burn’ the still fragile roots of the seedlings. In addition, it should be loosely packed so that the fine roots can penetrate it easily, and to avoid water-logging that would this would lead to rotting of the embryo. You can either use special seed compost or you mix ordinary soil with peat and sand in the ratio of 1:1:1. In order to kill all the germs present in this soil mix, place it in the oven for 30 minutes at a temperature of 100-120° C (210-250° F, Gas mark 9).

Time for sowing: The best time for sowing varies from species to species. You will find more precise information about sowing times in the respective plant descriptions. But there are a few general guide-lines that can be followed as a rule of thumb:

• You can sow seeds in a heated greenhouse, conservatory or on an indoor window-sills from February onwards. From mid-April to the end of May you can sow in an unheated greenhouse or conservatory, or directly in the chosen site, depending on the individual plant’s need for warmth.

Biennials that are sown in summer must protected during the winter with a layer of brushwood and placed for instance in an empty window box on the balcony.

Sowing: Pressed peat or Multi-pot flats are particularly suitable for sowing large seeds because they can be placed one per pot. Small seeds are best sown in seed trays , while very small seeds should be mixed with sand to prevent them from sticking to each other. The tray should be filled with seed compost – but not too deep – after which the compost should be smoothed to obtain an even surface. The seeds are sown loosely and then watered very gently with lukewarm water. The soil should never be allowed to dry out.

Dark germinators must be covered with a layer of compost while light germinators should only be pressed very lightly into the soil. It is important to follow the instructions on the seed packet.

If the tray has no cover or lid, you can use transparent plastic foil or a sheet of glass to cover the seedlings. It is essential to cover them in order to keep the air humidity high; this will encourage the seeds to germinate.

The best germination temperature is between 18-20° C (64-8° F) for most plants. Exotic specimens have a higher germination temperature while species indigenous top temperate regions will germinate at a lower temperature. When the seedlings have germinated the cover can be removed.

Pricking out and subsequent care: When the seedlings have developed leaves and have become crowded in the seed tray as a result, they must be separated. If they have been sown in the final container they should be thinned out, keeping only the most vigorous specimens. If grown in a seed tray they should be pricked out into separate pots. Use seed compost or a 1:1:1 compost, peat and sand mixture seed to which a little fertilizer is added. Place the plants in a light place but not in direct sun. Pinch out the tips to encourage the seedlings to branch out and become bushy. This means pinching or snipping off the middle stem as soon as the seedling has developed three leaf stems, or in the case of standards when they have reached the desired height. Tender plants should be hardened off before they are taken outdoors, being gradually accustomed to cooler temperatures.

Vegetative propagation

Vegetative propagation, unlike growing from seed, makes it possible to produce a clone of your favourite plant in a very short time. This type of propagation is recommended in the case of plants that take a long time to develop from seed to the stage of a fully-grown plant, or in the case of sterile plants that do not produce seeds. This includes herbaceous perennials, grasses and bulbs as well as trees and shrubs.

There are several methods of vegetative propagation. You will find which method is suitable for which plant in the individual plant descriptions.

Timing: Most plants are best propagated cuttings in spring or early summer so that the young plants can benefit from the increasing daylight. Woody plants can also be propagated from cuttings taken in summer or autumn. The most important prerequisite for successful propagation from cuttings is that the mother-plant should be a healthy, vigorous-growing specimen, since all its characteristics will be passed on. The containers and compost used to propagate cuttings are the same as for raising plants from seed.

Methods: Cuttings can be taken from the tips of shoots (tip cuttings), pieces of stem (softwood or greenwood cuttings) and hardwood cuttings. Some plants can even be propagated from leaf cuttings (from whole leaves or pieces of leaves).

Softwood cuttings taken from the soft tip of a one-year old stem during the growing period. In the case of woody foliage plants and conifers these are called greenwood or semi-ripe cuttings. Cuttings from conifers are best taken in spring when growth has slowed down a little.

When taking cuttings it is important to cut just below a leaf node. The cuttings should be between 5-10 cm (2-4 in) long and have no more than four pairs of leaves, otherwise it will grow very slowly. It is best to remove the lower leaves. Plant at a depth of about 2 cm (just under 1 in) in the compost mix, press the compost around it to secure the cutting, water generously, cover with sheet of transparent plastic film and place in a light warm place. A warm soil temperature will promote rooting.

Reduce the leaf surfaces of cuttings with large leaves by half. This will reduce evaporation and promote rooting.

Cover the cuttings with a transparent lid or a sheet of transparent plastic cling film. However, it is important to ventilate the cuttings now and again. As soon as new leaves begin to develop, the cover can be removed completely. After the cutting has rooted, it should be r-potted in a new container with fresh compost. Subsequently, treat the plants in the same way as seedlings, in other words put in light place, pinch out the growing tip of a stem and harden off.

Hardwood cuttings: In this case cuttings are taken from young shoots of deciduous and evergreen plants after the growing period, mostly in late autumn. They should be from 10-30 cm (4-12 in) long, not too thick, and have at least one eye. All the leaves must be removed. In order to remember which is the top and which is the bottom, cut the bottom diagonally. If you take the cuttings in winter, put them in sand and over-winter them in a frost-free place. In spring, they can be put directly into the compost so that that only one quarter of the length sticks out above the compost.

Crafting: this method is ideal when you want to combine the positive properties of a wild form, which usually serves as a stock, with those of the plant to be propagated, known as the scion. Grafting is a skill that needs a little practice, so it is best to first try whip and tongue grafting of two equally vigorous plants. In this case the stock and scion are cut diagonally and placed on top of each other. The scion should be at least 10 cm (4 in) long and have one bud. The grafting is secured with a rubber band. Roses are propagated by T-budding. This means that a bud of the plant to be propagated (scion) is inserted in a T-shaped cut in the wild form (stock), an operation that should be carried out in summer. The graft is then secured with bast and in spring the top part of the wild part (stock) is cut so that the bud of the scion can develop further.

Division: This is an easy way to propagate multi-stemmed plants such as herbaceous perennials and bamboos. The best time is spring when the plants are repotted. If possible, the roots should be slightly loosened before dividing the plant with your hand, a knife or two spades back-to-back, depending on size. The separate pieces are then simply repotted in fresh compost. Make sure that each part has enough roots and leaf buds.

Bulbils: When the foliage is dying clown, usually in early summer, the bulbils can be detached from the mother bulb and then planted in autumn after intermediate storage in dry place. They will also grow in pots.

Separation of offsets: This is a very easy way to propagate plants. Offsets are completely formed mini-plants with roots that can be separated from the parent-plant and just simply planted again. A well-known example is the agave.

Tips and tricks

• With cuttings and hardwood cuttings that are more difficult to root, it is advisable to use a rooting powder, available in garden centres, which will promote rooting.

• Usually, trimmings left after pruning in spring or early summer – for instance box or geraniums – can also be used as cuttings.

• Many cuttings will also root in water. Add charcoal to the water to prevent the submerged part from rotting.

• Hygiene is one of the prerequisites at all stages of propagation. In order to prevent infections, use clean containers and disinfected sharp knives.

17. April 2014 by admin
Categories: Tips and Advice | Comments Off on How to Propagate Plants Yourself


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