We don’t let dahlias go to seed early in the season, and here’s why: Every dahlia plant is growing with the “goal” of reproducing. To accomplish this, dahlias have two options: making seeds, and making tubers. If they are allowed to make seeds too early, then they think they’ve finished their job and begin to shut down for the season–slowing plant growth, tuber growth, and bloom production. The phrase “go to seed” literally means to finish up a life cycle and decline in productivity. We don’t want your dahlias to slow down yet!
If you pick your flowers and dead-head spent blooms, your dahlias have a reason to keep growing and blooming before they try to set seed and meet their “goal.” An added perk is that dahlias that aren’t allowed to set seed too early have better tuber production as they pour their energy into that option.
We recommend waiting until the end of the growing season (about 6-7 weeks before your estimated first frost) to let your dahlias go to seed. This way you get to enjoy the flowers all season long and the tubers will be well developed. It’s a win-win situation! Afraid of waiting too late to let some blooms go to seed? Check out Farmer Steve’s trick for harvesting semi-ripened seed pods and letting them mature indoors!
Now that our tubers have been in the ground for 4+ months, we are letting them set seed so that we can collect next year’s seedling adventures!