Soil Preparation.  Dahlia beds should be prepared several weeks prior to planting.  Beds should be rich in organic matter, be well drained and located in an open sunny location.  Some growers grow their dahlias in raised beds to ensure adequate drainage.  Dahlias do not require large amounts of nitrogen, but they do require ample amounts of phosphorous and potassium.  Use a fertilizer that contains twice the percentage of phosphorous and potassium as compared to nitrogen, ie, 5-10-10 or 10-20-20 .  Apply at the rate of 4 to 6 pounds per 100 square feet and incorporate into the soil to a depth of 8 to 12 inches.  Add sand or peatmoss to improve the texture of heavy clay soil.  If your  soil has a high sand content, the addition of compost or other organic matter with help water retention.  Dahlias prefer a soil pH in the 6.5 to 7.0 range (add lime to elevate pH and aluminum sulfate to lower pH).  If possible the soil should be tested the fall prior to planting as it takes several months or longer before a soil pH will be significantly modified.

Tuber Planting.   Do not begin planting until the soil has sufficiently warmed.  If planted too early, tubers may rot in cold waterlogged soil.  In warmer climates tubers may be planted in March but in most regions, planting should not begin until mid-April to mid-May.  Recommended spacing between tubers varies between 18 to 36 inches, depending upon eventual plant size.  Planting depth should be three times tuber diameter but not less than 3 inches nor more than 8 inches.  Place the tuber horizontally in the planting hole with the bud (eye) facing upward.  Some growers initially only put a light covering of soil over the tuber and then fill in the hole as the tubers sprout and grow.  Others totally fill in the hole at the time of planting.  Taller plants, 4+ feet in height, may require staking.  Stakes should be placed in the hole prior to planting to prevent possible damage to the tuber.  Place tubers 2 inches from the stake with the eye end closest to the stake.

Pest Control.  In areas with slug and snail populations a control program is a must if young dahlias are to survive.  Unless controlled, they will most likely continue to eat the new growth until the plant dies.  They may even devour new growth before the shoots emerge from the soil.  It is strongly recommended that a slug and snail control program begin at the time of planting and be closely monitored thereafter.  Some slug bait products now are effective for several months (Deadline Pellets) but most should be reapplied every several weeks.  The most common insect pests to dahlias are cucumber beetles, earwigs, aphids and spider mites.   It is difficult to control these pests without a spray program.  Sevin has been proven to be effective against the majority of these insects.

Post Emergence Fertilization.  Dahlias are heavy feeders and will perform better if given frequent fertilizer.  When the plants are about 12 inches tall, give each plant 4 ounces (1/2 cup) of 5-10-10 , 10-20-20 or a similar fertilizer scattered in a 2 foot ring around each plant.  Some growers fertilize every two weeks until the end of July.  Others follow a regime that provides only half of this amount.  Fertilizer should be watered in shortly after application.

Summer Plant Care.  After shoot growth begins dahlias should receive at least 1 inch of water per week.  After flowering begins plants should receive 2 inches of water per week.  To promote the development of a sturdier plant, the terminal shoot should be removed when the plant is 1 to 1½ feet tall and has set a flower bud.  This practice will promote plant growth, additional bud formation and the development of a strong vegetative structure that will provide more support for future flowers.

Cut Flower Care.  Flowers should be cut after they are fully developed – they do not open further once cut.  They should be cut during the cool part of the day, morning and/or evening using a sharp knife or shears.  Take care not to crush the stem.  To prolong flower life, insert the bottom 3 inches of the cut stem into hot water (approximately 170-180 degrees F) for a least an hour.  Some growers prefer to let the flowers remain in the water overnight.  Try not to subject the flower heads to the steam from the hot water.  Depending upon the flower type, this treatment may provide a vase life of a week or more.

Digging and Dividing Tubers.  Tubers may be dug several weeks after a killing frost has browned the tops of the plants.  If dug too early the tubers may not be adequately cured and may not overwinter well in storage.  Use a spade or pitchfork when digging to minimize tuber damage.  Beginning about a foot away from the plant, dig on four sides of the clump, gently loosening all sides.  Then insert the spade under the clump and lift carefully.  Be careful not to break the neck of the tubers.  Tubers with broken necks should be discarded during the dividing process.  Some growers believe the tubers become less fragile if allowed to air dry for an hour before beginning the washing and dividing process.  Use a garden hose to gently wash soil from the clump of tubers.  When dividing the clump, leave a segment of the crown (stem) attached to each tuber.  The eyes develop in this region and generally appear as small bumps.  Not all tubers will have an eye and therefore, all will not grow.  Once the clump has been totally divided, carefully wash off all remaining dirt from each individual tuber.  Allow the cut surfaces of the tubers to air dry for at least an hour, but preferably overnight, before putting into storage.

Tuber Storage.  There is no universal method of storage but most successful storage methods adhere to the following principles:

1.      Maintain temperature between 40 -50 degrees F.

2.      Damp storage medium (sawdust, straw, newspapers, etc.) that permit moisture exchange between it and the tubers.

3.      Do not store tubers in air tight containers, ie, plastic bags.

4.      Check on tubers several times over the winter.  Make modifications to storage conditions as required.  Discard any tubers that show rot.