Tallos morados

He estado leyendo las respuestas y lo primero que decir es muchísimas gracias! Por un lado veo cosas que pueden ser probables como bloqueo de nutrientes, fósforo o deficiencia de calcio y magnesio o pH desajustado, hoy me tomaré el día para tomar mediciones y corregir ese problema si es el caso y tomaré la recomendación de regar solo con agua durante 7 días a ver cómo responden mis niñas. Pero por otro lado problemas de climatización creo no tener, puedo controlar la temperatura y humedad a gusto independientemente de la que haga fuera de la sala de cultivo. Actualmente trabajo con temperatura mínima de 18°C y máxima de 23°C y una HR: 70%. Cabe remarcar que aunque haya variedad de genéticas en la sala de cultivo solo se podrán a florecer las super Lemon Haze, el resto se usará para hacer esquejes para la siguiente tanda☺️

Red stems are caused by stress. And a lot of things can cause stress for a plant. Wrong amount nutritions, wrong pH, too hot, too cold, pot too small, not enough light, too much light and 1000 more reasons. But it is always a sign of stress. Weird leave growth can be cause by genetics or the wrong amount nutritions.

If you want, I can reply in Spanish because your title is "Purple Stems." There are many causes for purple stems, and since I believe you are almost in my climate and conditions (I'm in Portugal), the purple stems might be a direct result of the genetics of the strains you are developing this season. You might also be experiencing what I have with the "grows" that are quite advanced this autumn, which usually happens due to the drop in temperature we've had in the Iberian Peninsula at this time of year. This year, in line with what we've seen in recent years, we have temperatures in the Peninsula that are almost like delayed summers until early November... I see you have three weeks in your "grows," and purple stems can occur when three weeks ago, with the sprouting of the seedlings, we still had days with 25 during the day and no less than 18 at night. With this three-week vegetative stage, I dare say that the purple stems are related to the conjunction of two factors: this week, temperatures have generally dropped, and we are experiencing these rains that give you very high relative humidity. If you add to that the genetics of the strains you are developing, the purple of the stems is nothing to worry about or raise alarms. In general, strains with notable cyanophytic genetics (blue or purple) or the presence of carotenoids (red and orange) tend to show purple leaves and stems when temperatures drop, and I'm sure that's what's happening with your grows. There's no light imbalance or lack of nutrients; it's simply the phenotypic response of a genetics that manifests in winter with lower temperatures and higher humidity. It's very simple to see that the "seedlings" that are now trendy with blue and purple colors, if planted in summer, have a hard time becoming the attractive colors for sales, and in autumn and winter, even strains that don't show them as such easily turn purple. Best regards, fellow grower, and keep pulling those beauties you have there!