Hello friend. Unfortunately can't see your images however if I may suggest, you may like to consider the following check points to rectify this situation.
Temperature:
The recommended day temperature with the cultivation of your "favourite plant" lies between 25 and 28 deg C. With higher temperatures the growth will slow down and the yield and quality will decrease (many growers experience this during summer). In the dark, other chemical reactions occur in the plant than in daytime. A lower temperature suits them best. The recommended night temperature lies between 15 and 20 deg C. With temperatures lower than 15 deg C the growth is obstructed, lower than 10 deg C the growth stagnates and lower than 5 deg C will damage the plant. The most ideal situation would be a grow room with both heating and airconditioning.
The roots are especially sensitive to low temperatures. The absorption of nutrients through the roots is an active process. This means that the root needs energy to absorb the nutrients, but also to be able to select these nutrients. The root can, to a certain point, choose which and how much nutrient it absorbs. This process can be seriously disturbed with too low a temperature, because then there is insufficient energy available for this process. Therefore you have to make sure that when watering the plants the water is approximately 23 deg C. With cultivation on rockwool the nutrient solution temperature is held constant with the use of a special twin glass sleeved aquarium heater that has a built-in thermostat.
Water:
It speaks for itself that the plant must receive enough water. Don't forget that the water needs of a plant, in time, can strongly differ. Freshly transplanted seedlings and cuttings require less water than a flowering adult plant. It is of great importance that the plant has a well developed and healthy set of roots for the optimal absorption of water (and the nutrients that will be mentioned here after).
Most of the water absorbed by the plant is evaporated via the leaves. By doing so the air in the grow room becomes humid.
Relative Humidity:
The humidity will decrease because of the ventilation in the grow room. To measure the humidity , you need a hygrometer. A high relative humidity is very important for the seedlings in the beginning of the cycle (between 60% and 75%). At the end it is important to keep the RH low (40% to 50%) because it could cause the buds to rot. If the humidity is too high, you need to exhaust more air. If the humidity is too low you could first try to increase it by hanging some wet (clean!) towels or sheets in the room and by often spraying the underside of the leaves (normal tap water). If this is not sufficient you might consider buying a humidifier.
Light:
The lamp must hang at a distance from the plants that will not cause any scorching of the leaves. This distance differs with the wattage of the lamp. I recommend a distance of: 400 Watt- 45 cm; 600 Watt- 85 cm; 1000 Watt- 105 cm. Don't hang the lamp any higher above the plants than necessary.
Hope this helps.
