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A simple guide to propagation

By John Molyneux. Although some think that propagation is complicated, there is nothing mysterious about it and it is worth the effort. Seeds and cuttings need 3 things; heat, light and moisture.

By sowing seeds or raising cuttings in a propagator rather than waiting for the soil to warm up you can get a head start on the season.

Greenhouse sensations - propagator

The first thing to consider is heat. Different plants need different heat levels from 18°C for basil to 35°C for a banana plant, most like to be at between 20°C to 22°C. To make sure you get the best results this heat must be constant, seeds and cuttings can't cope with fluctuations in temperature. Remember that on a windowsill the temperature can soar during sunny periods of the day, which will stop new growth, so pick your position carefully.

A heated propagator with a variable control is the easiest way to achieve the desired temperature and they provide heat to the bottom of the plants, which helps to get the best results. If you want to propagate in a greenhouse it is also more cost effective to use a heated propagator than to heat an entire greenhouse.

The second thing to consider when raising seeds and cuttings is moisture. When the seeds or cuttings are very young they need to feed through their leaves until they develop roots. Maintenance of high humidity around the leaves will protect them from wilting until new roots appear.

A covered propagator acts like a mini greenhouse maintaining high levels of humidity around the young plants. To help the plants generate moisture a propagator shouldn't be too tall, the taller the propagator the harder the seeds and cuttings will have to work to build up humidity.

Too much humidity, however, is bad for the plants and as they develop they will generate more humidity. This is where a propagator with large vents and a lid that can be propped open come in very handy.

Light is the third requirement for growth. You should take care to place your seeds and cuttings somewhere that gets plenty of light, but remembering that you need to avoid strong sunlight because you don't want to overheat your seeds.

Hardening off
Before planting out your seedlings need to be hardened and weaned off the heat and protection they've been used to. If plants are not hardened off, they may suffer a setback from which it can take several weeks to recover.

Greenhouse sensations - propagator

To make sure that your plants don't suffer any shock move them to a cooler protected place in a closed cold frame, cloche or small polytunnel about 6 weeks before the plants will be planted outside. As your plants harden up, the waxes coating the leaves will undergo changes in thickness to help reduce water loss.

If you would like to try this form of gardening go to Greenhouse Sensations for more information.