Stromboli F1 is your choice for the earliest calabrese in the season, from May, featuring vigorous, tasty domed heads and lots of side shoots. All this from an overwintered autumn sowing but they can also be spring sown for a late summer/autumn crop. Price for 20 seeds
This variety is resistant to cold induced growth inhibition allowing an overwintered crop with protection. In milder areas you may pick from January but generally the slower winter growth will see you picking from May. To try this sow in modules between September and early November, pot on or plant in your greenhouse border or polytunnel (50cm apart) where they are protected from the worst winter weather (use a floating fleece cover for extra thermal protection when the temperature drop below freezing). You can plant them into large pots which allows you to move them outside in the spring when you might need more room inside the greenhouse! Space spring sown plants 60-75cm apart, they will need more room as the growth tends to be larger in the warmer weather.
Cold induced growth inhibition is actually not fully understood… it is widely accepted that cold temperatures play a part but is also thought that low solar radiation also plays a role, spreading out young plants to maximise light levels is a good ploy. Floating fleece should only be used when necessary as it reduces the light levels. Cleaning the greenhouse glass and washing polytunnels will help maximise the light levels.