## 3 Results and Discussion
### Anova Analysis
In addition, it is possible to see clearly that the _Distance_ plays the most significant role for both the responses, _Dry mass_ and _Stem dry mass_, even if for the first a not negligible effect is due to the proportion among hyper red and deep blue. To promote the dry mass, not only the lowest _Distance_ must be selected but also a 1:1 proportion among hyper red and deep blue LEDs that correspond to light combinations LR33 and LR13. Different behavior can be observed for the responses _LAI_ and _Water_ (Figure 6). _LAI_ (Figure 6a,b) is mainly affected by _Distance_ and only a slight effect is observed for the _White_ LED. Conditions that optimize this parameter are lower _Distance_ and the absence of _White_ LED, independently of the ratio among hyper red and deep blue (Light combination LR22, LR33, LR44). Particularly interesting is the evaluation of the _Water_ necessary to irrigation over the experimentation (Figure 6c,d) because this one is the only parameter that we desire to minimize to save an important natural resource such as water. As expected, the lower _Distance_ increases the water consumption, as that more near the lights, the higher the need of water for plants due to the artificial light heating. The _White_ LED alone is not particularly relevant for this response as can be seen by comparing Figures 6c and 6d, because almost the same range of mass of water is necessary; nevertheless, a different shape of the response surface is detectable as the interaction with the other parameter is reliable. Without white LEDs, the light combination LR22 must be preferred to reduce the amount of water to employ (Figure 6c), whereas no particular difference can be noticed among the LEDs combinations LR12, LR13, LR14 if the same distance is applied. This result suggests that the _White_ LED addition must be well considered to reduce the water consumption. At the same time, the lower _Distance_ that seems to promote that certain growth parameters (Dry mass, LAI and Stem dry mass) should be increased with the aim to minimize the water consumption. Thereafter, it is interesting to observe quantitatively how much each independent variable, in single or interaction, is capable to affect a specific property, considering each elaborated model. This can be observed from Figures 7-10, where size effects were reported for each significant response, by grouping them for specific basil parts. Regarding responses related to the overall plant (Figure 7), _Distance_ plays absolutely the main role for all the responses; nevertheless, a negative effect is reported for _SLA_. This means that the same _Distance_ that is capable to promote some properties (e.g., _Height_ or _LAI_) is also responsible for a reduction of the _SLA_ parameter. As shown from Figure 7, for _SLA_ parameter the reduction due to an increasing distance can be recovered by increasing the _HR:DB_ ratio, thereafter introducing more hyper-red LEDs with respect to deep blue. Considering the two responses related to leaf growth (Figure 8) a reliable and positive effect is associated to _Distance_ and _White_ LEDs employment in single and in interaction. However, the effect of the ratio _HR:DB_ is negligible for _Leaves wet mass_ and strongly negative for _Number of leaves_, suggesting the need to employ the lights combination LR44 to promote the leaf number, as confirmed by a previous study [28]. Evaluating the responses related to stem properties (Figure 9), again it is possible to detect a strong influence of the _Distance_, as it has a strong effect as single factor and in interaction with _HR:DB_. Even if in this case, a competitive effect emerged related to the response _Stem length_, that is affected in a positive way from _Distance_ in single factor but a negative way when its interaction with _HR:DB_ is considered, leading to a restrained range of light combination-distance conditions capable to promote this property. A similar situation describes _Stem dry mass_ and _Stem wet mass_ but with restrained size effect with respect to _Stem length_.