Dahlia Care Guide

When Your Tubers Arrive

Your tubers will arrive dormant and ready to plant. Open their packaging and store them in a cool, dry location until you're ready to begin.

Planting outdoors should be done when soil temperatures are consistently above 10°C (50°F) and all danger of frost has passed. For gardeners in Saanich, this is usually early May. Check your local last frost date if you're unsure.

To get a head start on the season, tubers can be placed in potting mix somewhere warm and bright to encourage early sprouting.

Planting

Dahlias require full sun — at least 6 hours of direct sunlight daily. Choose your spot accordingly.

Dig a 4–6 inch deep hole and place the tuber horizontally with the eye facing up. You can add some bone meal and a handful of compost before filling with soil. Space plants at least 12 inches apart, as dahlias grow quite large.

Important: Do not water until you see the first green shoots emerging. Watering too early is one of the most common causes of tuber rot.

Growing

When plants reach 8–12 inches tall, pinch off 3–4 inches from the top of the center stalk, just above a set of leaves. This encourages the plant to branch out, resulting in a bushier, more productive plant with better stems for cutting.

As your dahlias grow, staking is recommended. Plants can reach several feet tall and become top-heavy with blooms, so providing support early prevents broken stems later in the season.

Harvesting & Vase Life

Since dahlia blooms don't continue to open much after cutting, wait until flowers are fully open before harvesting for the best results. With proper care, dahlias typically last 5–7 days in the vase.