That depends on when you want to harvest them.
- Earlies can be sown under cloches mid February to harvest early June
- Earlies can be sown under cloches in March to be harvested June to July
- Early and maincrop can be sown April to be harvested mid July to August
- Maincrop can be sown mid May to be harvested August
- Maincrop can be sown June to be harvested September
- Maincrop can be sown July to be harvested October