As I mentioned in my last piece, seeds which are sown early in the year really need to be placed under lights if they are going to thrive. As amateur growers we get excited about sowing as soon as possible in the year when it can often be better to wait a few weeks until light levels are much longer and brighter. The other point to remember is that sowing can be done in a confined space but as soon as the young plants are through and ‘pricked off,’ they will require much more room. This in turn requires heat and off course,expense.
Above is a picture of our propagator which has thermostatically controlled heating cables and a tube heater at the rear. Two fluorescent daylight reflector tubes hang just above the propagator itself and are on for 16 hours a day. Fluorescent light is the nearest thing to daylight and is ideal for most plant species. Reflector tubes make sure that the majority of light shines downwards onto the plants.In the foreground is a max/min thermometer just to keep a check on the temperature extremes within.
The other picture is of tomato seedlings which have been under the lights. These are sturdy plants showing very little signs of elongation and are now at the stage for ‘potting on.’ Once potted, the growing temperature is reduced somewhat and tends to match the natural light levels, so keeping the plants in good condition. Always remember that your glasshouse heater must be able to cope with the coldest of conditions and that all electrical equipment is water resistant.
To any horticulturist, this is one of the best tasks of the year. Seed sowing has to be the most theraputic and exciting time as we set off on a seasons journey that will, once again, be a reflection on our skill as a grower. OK, you can throw in the vagaries of the weather and the part time nature of amateur gardening but at the outset our aim is to achieve a quality crop or floral display.
Correct seed sowing is a skill and not one that I was allowed to carry out until the foreman thought I could do it properly. Hygiene is also an important factor and all containers and growing media involved should be spotless. Unfortunately amateur compost can be of poor quality so never go for cheapness. Peat based medium is still the finest for sowing purposes but even here cheap compost may be a blend containing too much sedge peat which can result in poor germination.
When filling containers make sure that the compost is evenly consistent and never over firm or it will become waterlogged when watered. Even compost and even sowing will result in even seedling growth. Also, never try to cram too many seeds into a container, rather use two and sow more thinly. When sowing fine seed, such as begonia or antirrhinum, seed can be mixed with brickdust or very fine dry sand which shows up on the compost surface. Watering first, before sowing, is also beneficial with fine seed.
Once seed has been covered, if required, the final task is to label the container and even this task has a correct procedure. The date of sowing should go across the top then the species and variety are written down the label starting below the date. In this way each label can be read without removal once the seedlings are through.
Once sown, a small pane of glass can be placed over the container to keep things humid along with a piece of newspaper which will prevent the sun from overheating the air between the compost and the glass. Once through both are removed.
One final point to consider is the fact that the heat in which young plants are grown must correspond with the light levels and day length. Early in the year when light is poor, seedlings will required extra day-length in order to stop them becoming drawn. All our early seedlings went under florescent light for 16 hours in order to prevent this happening and to produce a quality plant. Something to consider carefully.