Dahlia's and ventilation and light, don't cut off the leaves and take away the Chlorophyll

Leaves are essential for photosynthesis, the process by which plants convert light into energy (sugars) to fuel their growth. When planting too close together plants can get mildew, from lack of airflow (ventilation) and often inconsistent watering. When plants are unhappy they take the Chlorophyll back from the leaves before they drop them. Chlorophyll takes a lot of energy to make. Don't be too quick with the snips. Look at the underlying reason for leaves dying. Let the plants take it back before you chop the leaves and learn by watching for next year. For more detailed growing instructions join our ‘Grow-A-Long’ and for busy gardeners you can now plan ahead with our Handbooks, see my website for all the videos and details https://zoewoodwardgardening.com/ More on Dahlias here Lots of love Zoe