Many gardeners had a problem with this last season and quite a few people who I've talked to lost many of their plants to this fungal disease.
Here are a few suggestions on ways to avoid blight.
- Grow varieties that are resistant such as Ferline & Legend.
- Spray with a systemic fungicide (Dithane 945 in the UK).
Find some way to provide cover to keep rain off leaves.
- Sow later in the season with early season varieties.
- Avoid condensation in the greenhouse with greater ventilation.
- De-leafing (to a degree) helps air circulation.
- Keep plants as healthy as possible ... seaweed extract stimulates growth and helps plants combat disease.