Propagation - Seeds and cuttings can be raised and grown on for their whole lives in hydroponics.

Many of the basic principles of propagation are the same in hydroponics as in soil growing. Maintaining the correct levels of water, temperature, light and air are vital to success. Many of the hydroponic growing media help with this and so hydroponics can be used as a propagation method for plants which are destined to be planted out in the soil.

Most propagation is done in a growing medium with small particles (perlite and vermiculite) or in rock fibre cubes (Grodan). The Hydroponicum's propagation kits include Gold which is a mixture of perlite and vermiculite.

Hydroponicum Tray propagator - position watering corner in corner of tray and fill rest of tray with Gold. Moisten the Gold by slowly adding about 1 litre of water into the corner.
Seeds can now be sown or cuttings inserted into the growing medium.

Seeds - Depth of sowing is as for soil growing - look at the seed packet for advice. In general, fine dust-like seeds can be sown on the surface, larger seeds should be covered to a depth equivalent to the size of the seed. Sow thinly to allow them space to develop and so that they can be easily separated when it is time for

Cover with fleece to retain moisture and place the propagator in a warm place, approx. 21 o C or 70 o F (some seeds need higher temperatures see seed packet for advice). Do not allow the surface to dry out - add more water as necessary.

Most seeds do not need light at this stage so a warm dark place is fine. Check daily for signs of germination and put into good light immediately there is sign of life.

Cuttings - If you already have access to healthy plants that display desirable characteristics it is possible to clone new plants from them. These new plants will be genetically identical to the stock plant and, provided that the environmental conditions are constant, the new plants should perform exactly as their parent did.

 There are many different techniques for preparing cuttings but there are general principles which apply to all. Selected material should be healthy and vigorous. Stems should be thick and firm and foliage should be dark green.

Most species are propagated from softwood or semi-ripe shoots. Remove selected piece from mother plant with sharp scissors, cutting just above a leaf-node or side shoot. Final cut should be made with a sterile scalpel or clean sharp blade just below a node or leaf junction. Rooting compounds (powder or gel) can be used if desired.

Insert the cuttings to a depth at which they will support themselves, gently firm the Gold around the stem.

Aftercare - Allow good light either from a natural source or a growing light.
At the early stages a seedling requires no nutrients. They are using the energy resources within the seed to sustain their early development.

When a seedling grows its first set of "true leaves" (ie the ones which grow after the initial pair of 'seed leaves'), or when a cutting has developed roots it will require nutrients.

Gold growing medium has a small initial supply of nutrients in it so plain water only is required to raise your young plants to the point of planting out of the propagator.

With all other hydroponic growing media a weak nutrient solution should be applied at this point.

Propagation using Grodan / Rockwool Propagating Cubes - The 1" Grodan cubes are an ideal medium for propagation. They are available in plastic trays which hold 150 cubes or as a slab of 200 cubes which can be used as a refill pack for the trays.

Decide how many seeds or cuttings you are going to sow. It is possible to cut the tray into smaller sections to suit your purpose. For instance a block of 6 cubes by 10 will fit neatly into a standard seed tray propagator with a clear perspex cover.

Insert seeds carefully into the holes marked out on top of the cubes. Don't push seeds in too far, just enough to hide them. A few strands of Grodan should be teased over the hole to ensure that seeds are covered.

Place Grodan tray in a warm place. Covering the tray with a piece of horticultural fleece will help reduce evaporation and keep up the humidity level. Light is unimportant for seeds until the seedlings begin to emerge but MUST be supplied as soon as they do. Cuttings require semi-shade not direct sunlight.

Ideal germination / rooting temperatures for most species are in the range 20 - 25 o C. These temperatures should be maintained as constantly as possible during the germination period. Heat is best supplied from underneath (bottom heat) to warm the Grodan and encourage root cell initiation.

Check the moisture level of the Grodan EVERY day. If you just squeeze a corner of a cube, water should come to the surface. If it does not then you should give the whole tray a light sprinkle of lukewarm water. The biggest mistake with Grodan is to keep it too wet. Always allow free drainage underneath the tray and NEVER let your Grodan stand in a puddle of water.

Once your seedlings begin to appear you will need to give them plenty of light. A warm bright windowsill might do but a greenhouse or artificial lights will be best. You should still leave the fleece in place (if used) until the seedlings are ready for transplanting.

As soon as cuttings start to develop roots you will see them perk up and start to produce new growth from the tip. At this point the plant will require some nutrients. Supply a weak nutrient solution as required.

It is still important to maintain temperatures in the mid twenties for as much of the day as possible. Keep checking your Grodan cubes for signs of drying out.

Once your seedlings or rooted cuttings begin to show roots at the bottom of the Grodan cubes they are ready to plant. Lift the little cubes carefully from the tray. They can be planted into a larger rockwool block for placing in a Nutrient Film Technique (NFT) system or into any other hydroponic growing medium. The small plants are also suitable for planting into soil or compost.