With thanks to David Metcalf from the NVS for sharing his methods for growing onions at exhibition level practices should you wish to try a different approach. Growing to exhibit may not be for all of us however, there are many considerations, skills with tried and tested methods not to be ignored, in which we hope you can make good use of in your own growing practices...
Seed is sown in my greenhouse during early December with an ambient temp. of about 17°C It is sown in a fine seed compost ¼” deep and germination takes 10/14 days. After emergence it takes about 3 weeks for the second true leaf and a small root system evident. The seedlings can then be pricked out into a good peat based multi-purpose compost in small pots or large modules.
At this time, artificial lights can be applied for 12hrs through the day to enhance the poor daylight at this time of year, and until they go to the allotment in mid April. At this point they will be showing 8/9 leaves.
After approx. 4/5 weeks they will require potting on into 3ltr pots of multi-purpose compost with added John Innes compost and a small amount of fish, blood and bone fertilizer to keep them growing. I support them with a split cane and twist tie until harvesting, otherwise they may fall onto the compost and grow crooked.
Watering is once per week until the weather warms up, then twice weekly, and in hot periods every other day. Shading is applied with frost fleece to prevent the plants from scorching, or they stop growing.
Throughout their growth they will need light sprays of thrip deterrent and maybe red spider killer from June. I dust my plants with PY bug killer which is considered to be organic. A light and airy atmosphere is a must to prevent botrytis from prevailing.
As harvest time approaches usually end of July the bulbs can be measured and recorded using a soft tape around the girth. The largest ones can be lifted with the others left growing to reach the same size. I remove the green leaves and roots at lifting time and take the bulbs back to my garage where they ripen prior to dressing for showing.
