I am bringing on Begonia tubers in small pots indoors which I bought from a reputable online company. I planted them around three to four weeks ago and have them sitting on units in a South Westerly facing bedroom which gets a fair bit of sun. The problem is some of them seem to be shooting as in growing too tall too soon. I thought they were getting too much sun so have since tilted the blinds to shade them more but they still seem to be shooting. The heating is on for a bit in the evenings but the room doesn't get overly warm. Any suggestions or advice would be most welcome.
Please see photo below.
Please see photo below.