How to Plant Semi Cactus Dahlias

Select a location that receives full sun for 6 to 8 hours a day. Although semi cactus dahlia will grow with less sun, blooming will be inhibited.

Till the soil to a depth of 8 to 12 inches. Remove stones, roots or other debris from the soil. Smooth the area with a garden rake or hoe.

Spread a 3 to 4 inch layer of well-rotted manure or compost over the planting area. Add 2 to 4 lbs. of 10-10-10 or 8-8-8 fertilizer per 100 sq feet.

Till the organic matter and fertilizer into the top 6 to 8 inches of soil. Organic matter improves drainage and promotes good air circulation, while fertilizer provides the nutrients your semi-cactus dahlias need to grow.

Dig a hole approximately 4 to 6 inches deep for each dahlia tuber. Refer to the planting directions with your tubers to determine the appropriate spacing between plants. Typically shorter varieties require 12 to 18 inches, while larger varieties may require 2 feet or more between plants.

Place tubers in the soil with the "eyes" facing upward. The "eyes" are the beginning of the sprouts, and you may see tiny yellow or reddish buds forming there. These will continue to grow once planted.

Cover the dahlia tubers with 2 to 3 inches of soil. Pat the soil down with your hands to secure the bulbs and remove air pockets.

Water thoroughly to moisten the soil to the planting depth of the bulb. Keep the soil evenly moist -- but not soggy -- until new growth appears.

Fill in around the tubers with soil until it is level with the surrounding soil as the plants grow.