Sowing and Growing in a Propagator
Date Posted: 01 March 2013
Sowing and Growing in a Propagator
Seeds need moisture, oxygen and warmth to germinate and one of the best ways to get them off to a flying start is in a Propagator.
There are three types of propagators available:
Unheated – These are non electric and consist of a bottom tray and a clear lid
Heated – These are electric and once plugged in will heat up and remain at a constant heat.
Heated with a Thermostat – These are electric with the addition of a thermostat and will maintain a specified temperature.
Propagators are available in various sizes to suit any growing position there is even one specifically designed to fit on your windowsill.
Place your propagator on a windowsill, on a surface as near to the window as possible or in a greenhouse, but not in the midday sun. Switch on your propagator a few hours prior to use to allow the elements in the base to warm up.
Sowing your seeds
Seeds can be sown in trays or pots which should be clean, fill them with good seed compost nearly up to the rim then tap the trays/pots gently on a hard surface to settle the compost removing any air pockets. Level the surface of the compost and firm lightly with a mallet or tamper. Tip the seeds into the palm of your hand, pinch between your finger and thumb and sprinkle thinly and evenly onto the surface to ensure accurate distribution of seeds. Very small seeds usually do not need to be covered over, medium seeds generally need covering to their own depth with compost, use a soil sieve to get a fine and even coverage, large seeds e.g. courgettes, beans need to placed in a shallow holes and covered, these are better sown in pots. Their seed packets will give full sowing instruction specific to their variety. Place a label in each tray/pot with the name, variety and date when sown, and if the seeds are large enough the number sown, on the back of the packet I write the date and number sown which gives me an indication of how many are left in the packet I also have a notebook where I record this information and I can also make notes regarding germination success and sowing times etc.
The compost needs to be moist but not soggy as the seeds may rot or it can lead to fungal problems, to avoid washing the seeds away water from below by placing the containers in shallow trays of tepid water until the moisture is visible on the surface of the compost, allow surplus water to drain away then place the pots in your propagator with the lid vents closed.
Check your propagator daily and water if the compost begins to dry out. Once your seedlings emerge open the lid vents half way to release condensation and allow the plants to breathe. Once the seedlings come into full leaf open the vents fully or remove them from the propagator and place in a warm, light position, turning them each day to keep them upright as they will lean and grow towards the light.
Once your seedlings are large enough to handle they can be pricked out into individual pots or seed trays into a general purpose compost. To lift out loosen the compost under the seedling with a dibber and hold them by their leaves taking care not to damage their stem or roots. Refer to the seed packet for further growing/planting instructions specific to each plant.
Propagators are cheap to run, to keep them as economical as possible keep them full while they are in use, replacing your germinated seeds with newly sown trays. Seeds do not all germinate at the same time so plan ahead, germination times are usually specified on the seed packets, plant slow-growing seeds first e.g. peppers, aubergines followed by tomatoes and herbs and then fast germinating seeds such as lettuce, salad leaves, marrow, courgettes and cucumbers.
'I wouldn’t be without my propagators I have two 52cm heated propagators which in spring are both full for quite a number of weeks, having two gives me that extra room to sow my seeds thinly and individually in pots, which avoids root disturbance when transplanting, and also to repeat sowings if germination has not been as successful as expected.'
Propagators are a worthy investment which will increase the germination success of your seeds, enable you to sow and grow earlier and to grow more varieties.
Have a look at our guide How to grow Seeds in Trays and Pots for more information.