**5.2 Temperature regimes**

The parameter of mean daily temperature might be misleading, as it hides a lot of important information about the actual temperature regimes. For example, during most of the season (from July to April), the mean daily temperature at Ramat Negev and Besor is quite similar, with slightly lower winter values at Ramat Negev. From November to late February, Paran values also merge with those of the other two regions (**Figure 6**). However, the extremum temperature means reveal significant differences between the three regions. Unequivocally, mean RN minimum temperatures are the lowest throughout the season, while Besor is the warmest during winter,

#### **Figure 5.**

*Mean daily ground-reaching solar irradiation during the strawberry season at Besor, Ramat Negev (RN), and Paran research sites that represent three different strawberry-growing regions in southern Israel. The map indicates differences in ground-reaching irradiance in February. Data and map were extracted from solar radiation Atlas [20], expressing means of 19 years (1999–2017).*

#### **Figure 6.**

*Temperature regime during the strawberry season, from launching propagation on 1 July (DOY 182) until the end of the harvest period on 30 April (DOY 120) at the northwest Negev (Besor), Ramat Negev (RN), and the Arava Valley (Paran). Data present means of maximum, mean, and minimum daily temperature over years 2010–2021, using official meteorological stations.*

and Paran is the warmest during fall and spring (**Figure 6**). Paran displays the highest mean maximum temperatures throughout the season, but from mid-November to late January, they are quite similar to those in the other two regions. During summer and early spring, Ramat Negev is warmer than Besor, but during December–January, daily maxima at Ramat Negev are the lowest (**Figure 6**).

The differences in solar radiation and temperature regimes introduce opportunities, as well as certain limitations for strawberry cultivation in each region. Relatively low temperature during summer and early fall enhance floral induction in most of the cultivars. Therefore, propagation and plug plants preparation are advantageous at the cooler Ramat Negev. Planting can take place first at Ramat Negev, as early as at early September, with the advantage of earlier harvest. However, low night temperatures often restrict plant development and fruiting during late December and January. The optimum planting time at the northern coastal Negev (Besor) would be late September, with the advantage of more stable mid-season (January–February) cropping due to the milder winter temperature. In the Arava Valley (Paran), the strawberry season is pretty much confined to late December to February; with optimal temperature and favorable solar radiation both plant and fruit development are enhanced, and fruit quality (Brix) is excellent. Nevertheless, the rapidly increasing temperature does not permit season extension there, whereas most of the yield

*Winter Strawberries Production in Greenhouse Soilless Culture under an Arid Climate… DOI: http://dx.doi.org/10.5772/intechopen.104390*

of the two other regions is produced during March and April. The climate differences between the three regions may open opportunities for cooperation, exploiting the relative advantages of each region while covering possible gaps in production, altogether generating a complete and complementary strawberry marketing season from November until April. Thus, propagation and production of highly productive plug plants can take place at Ramat Negev for the three regions, whereas the production season can be allocated to Besor and Ramat Negev for the early- and late-season, and Besor and Arava Valley for the mid-season marketing.
