Cultivation success depends to a large extent on the right choice of variety.
The different behavior towards the length of the day and other environmental factors determine the suitability of the individual varieties for the different types of cultivation (see also advice 257). As a result, the lettuce range is divided into several variety groups.
The varieties for cultivation under glass and foil are equally suitable for the spring- and autumn use of small greenhouses, Foil tents and cold frames as well as partly for the earliest outdoor cultivation under perforated flat foil. In later outdoor plantings, they shot without prior head formation.
The special early outdoor varieties should only be used for plantings until around mid-May, since later planting dates also lead to bolting without normal head formation.
A third group of varieties, those between these early-free range- and the summer varieties, is of particular importance for the allotment gardener, because it can be used for subsequent plantings from the end of March/beginning of April to the end of August. The varieties in this group produce relatively large heads, are quite insensitive to unfavorable weather and usually remain 8 to 10 days harvestable, before they bloom. The pronounced summer varieties require a longer development time until they are ready for cutting and are particularly heat-tolerant. In this group, the varieties with red-brown tufted binders and cap leaves are particularly striking. They are preferred to green varieties, being less frequented by aphids. In addition, they are usually characterized by particularly delicate inner head leaves.
Also among the summer varieties are the so-called Krach- or iceberg lettuce. They require the longest development time, but reach head weights of over 500 g.
Finally, a small group of varieties should be mentioned, which are particularly suitable as winter lettuce.
