Dahlias like warm weather and fertile, well-drained soil located in a sunny place is most ideal. Heavy clay and tight soils should be loosened with sand and humus material. Moisture and plant food retaining qualities can be given to sandy soils by adding humus. I like to put some fertilizer on top of the soil after I plant.  This will then work into the soil throughout the summer.

You want to stake the Dahlias so that they do not fall over.  In terms of pests, Aphids, Red Spiders (mites), Leafhopper-, Japanese Beetles, Thrips, and Corn Borers are the most common dahlia pests.

If large blooms are to be produced, disbudding is necessary. Buds form in clusters of three. As soon as they can be seen, break off the two side buds, leaving the center bud. When the center bud develops a stem about 6 inches long, other buds will appear at the base of the leaves on the same branch. These are leaf buds and, if allowed to develop, they will produce a small bushy effect and imperfect flowers. Only one terminal bud should be left on each branch if large perfect flowers and long sterns are wanted. Plants should be gone over about once a week during the growing season with the object of disbudding.

 The high point of growing dahlias is enjoying the flowers. They may appear any time in July, depending upon the varieties and types you're growing. To use dahlias as cut flowers, cut the blossoms when they are fully open. Use sharp shears or a knife to cut a long enough stem for the use intended. Plunge the cut ends into warm water immediately. When you're ready to arrange the flowers, cut off about 1/4 inch of the stem base and place the stems in warm water. Be sure to use a sharp knife or shears. Using floral preservatives or changing the water every 2–3 days will increase the life of cut flowers. Another useful technique is to place the basal inch of each stem in boiling water for 1 minute while shielding the leaves and upper stem and flowers from the steam and heat.