Dahlia Growing Tips

Growing Dahlias is easy and super rewarding once you get down a few easy concepts.

GROWING ZONE: Dahlias are considered annuals in Zones 3-7 requiring the tubers to be dug up and overwintered indoors where they wont freeze. They are perennial in Zones 8-11.  If you're unsure of your growing zone please confirm using the USDA map in this link by entering in your zip code.  https://planthardiness.ars.usda.gov/ 

PLANTING: Dahlia's generally like the heat! Cold wet spring conditions can lead to the tubers rotting. Make sure to plant in the late spring after all threat of frost has passed and weather has consistently warmed. My last frost date is April 25th but I will wait until the second half of May to plant to guarantee no long cool snaps. Even if the tubers don't rot cooler temperatures will slow their growth. 

Plant dahlia tubers about 6 inches deep. I've seen many different spacing options but what works best for me has been 2 rows of tubers planted 1 foot apart in each direction. Staking dahlias is highly recommended, especially in windy areas. I like to set up 4 foot T-posts with netting to help stabilize them so they don't flop over in summer thunderstorms.

Plant dahlias in an area where they receive full or mostly full sun. Insufficient sunlight will impact the number of blooms you get. Flowers appear mid to late summer and will bloom till the first hard frost. 

WATERING: Dahlias like consistently moist but not soggy soil. I previously lived at the Jersey Shore so my yard/ soil was sand. No matter how much water I gave them they wilted in the afternoon sun. Amending the soil to have more organic matter should help with water retention. Currently, my farm is in Hunterdon County NJ where the soil has a lot more clay/ organic matter naturally. I don't have to water the dahlias nearly as often and they have produced a lot more flowers because of the consistent moisture of the soil. 

PINCHING: Pinching your dahlia plants is highly recommended. Once the plants are about 6 inches tall and have 3-4 sets of leaves, pinch out the center of the stem. This will allow the plant to bush out with more side shoots equaling more flowers! If you do not pinch a lot of times you'll end up with one super thick stalk and not many flowers. 

OVER WINTERING: If you live in a zone where dahlias are not hardy, you will need to dig the tubers up in the late fall and store them someplace where they will remain cool but not freeze over the winter. There are many many videos on you tube you can look up to see how farmers do this. A little bit of trial and error is likely going to happen before you find the method that's right for your conditions. 

My method is I dig them up around Halloween, wash the dirt off with the hose, set them out to dry for 24 hours, and then pack them away in plastic bins filled with vermiculite. I store them in my basement which is usually in the mid 60's temperature. NJ winters are extremely dry humidity wise meaning the plastic container is a must to keep them from shriveling up.