I start the seeds in 4 inch pots OR you can start them in the little pony pack ( six to a pack ) or in a any kind of container. You want to use a light potting soil, one that drains easily. Water,but do not keep the soil wet as you do not want the seeds to rot.
One the seedling pops through, water when soil feels dry. The plants can hang out in a 4" pot for about 4 weeks. If your temps aren't high enough to set outside, transfer them into 1 gallon containers.
The warmer your temps the faster they will grow.
I use an all purpose fertilizer, Miracle Gro and the like is not suggested for dahlias. Just use a 4-4-4...oraganic, a sprtiz of fish emulsion during the early growing time is fine...
PREPARING THE SITE
Dahlias do not require any more preparation than other bedding plants that you might be planting. Dahlias do well in high organic matter soils. We recommend working a 1â€-3â€ layer of compost into the top 12â€-14â€ of soil. You can also work in manure or a balanced commercial fertilizer at this time. Dahlias are heavy feeders and will benefit from additional fertilizer.
WHEN TO PLANT
Dahlia plants or cuttings provide the most flexibilty and the earliest start to the blooming season. They can be planted any time after the threat of frost has passed. They may be planted earlier if frost protection is provided.
Dahlia tubers should not be planted until soil temperature in the top 6 inches is at least 50 degrees. Tubers planted into cold soils will lay dormant and risk decaying before they sprout.
PLANTING YOUR DAHLIAS
The most successful method for planting dahlias is to use well established plants that are well rooted and have 2-3 pairs of leaves. Remove them from their containers and plant up to the first pair of leaves. Water them well on the day they are planted and water every 1-2 days for the first week in the absence of rain. After the first week to ten days reduce watering to weekly until they begin to actively grow.
Planting dormant tubers requires proper timing, soil temperature, and patience while waiting for them to sprout. Dahlia tubers should be set flat into a hole 4-6 inches below the soil surface with the eye pointing up. If the soil is dry, water them once on the day they are planted. Planted into wet soil they will need no additional water. Do not water tubers again until the shoots have emerged above the soil surface. This could be 2-3 weeks after planting. Dahlia tubers are very susceptible to rotting, which is why we recommend planting cuttings or plants.
Dahlias vary widely in plant size so there is no standard recommendation for spacing. Mature dahlias are usually as wide as they are tall, so a good guideline is to plant them 1/2 their height from structures or other plants. This means planting 6â€™ tall dahlias 6â€™ apart to realize the full potential of the plants. However, to maximize bloom production, space dahlias 1/2-1/3 their height apart, leaving more space on at least one side to allow access for bloom cutting and plant grooming.
STAKING YOUR DAHLIAS
Your plants will look better and be more manageable if you plan to provide some type of support for them. Dahlia blooms can be very heavy and nothing is more depressing than having a beautiful new bloom crash to the ground because it was not staked! Stakes should be driven at the base of the plant and be 1â€™-2â€™ shorter than the expected height of the plant. Tie the primary stalk to the stake in one or two spots as the plant grows. Maintaining your plants so that they grow upright, rather than sprawling will ensure strong growth and maximum flower production.
WATERING AND FERTILIZING YOUR ESTABLISHED DAHLIAS
After your dahlias are 6â€-8â€ tall and have 3-4 pairs of leaves you should supplement them with a water soluble nitrogen fertilizer. It is best to apply it by dissolving it in a watering can and dispensing a meaured amount to the base of each plant, or by injecting it directly into drip or soaker hose at the base of the plants. This should be repeated every 3-4 weeks through the season until about one month before the first expected frost. This will maximize their growth and flower production, creating strong plants with strong stems.
If your soil is sandy you should water lightly every 3-5 days. If your soil is heavy and has a lot of organic matter you can water every 7-10 days. Large, mature plants require more frequent watering than small plants. Dahlias do best if the foliage is kept dry. Occaisional overhead irrigation is ok to wash off plants or incorporate fertilizer. Wet blooms are prone to disease and can cause plants to topple. If your plants appear to be wilting increase the water frequency. Afternoon wilting on extremely hot days is natural as long as the plants appear to recover in the evening after the temperature has gone down.
GROWING DAHLIAS IN CONTAINERS
Dahlias do very well when grown in large pots or garden boxes. This is a good strategy if you have limited space, want to use dahlias as patio decorations, or if gophers are a serious problem. They do best in containers that hold at least 12â€-14â€ of potting medium. Smaller containers will require more frequent watering.
Always used the highest quality potting mix that you can find. If your container dahlias are regularly wilting even when watered regularly, move them to a location with less afternoon sun to keep them from overheating.
Dahlias are the perfect cut flower producer. They respond to cutting by producing more blooms. Dahlia plants that have blooms removed regularly will produce more blooms than those that have blooms left on the plants. When cutting blooms from your dahlias take a fairly long section of stem. Plants cut back fairly hard will produce stronger regrowth from further down the stalk than if just the bloom is cut. Dahlias blooms are borne in clusters of three. Some growers choose to remove the two side buds to promote the size of the terminal bud. This is purely personal. You may choose to disbud some plants and leave others to grow naturally. Show dahlias are always disbudded.
If you are not regularly cutting blooms from your plants be sure to at least remove the spent, withered blooms on a regular basis. This is called â€œdead-headingâ€ and is strongly recommended to reduce disease and unsightly debris on the foliage. Dahlias that are not regularly â€œdead-headedâ€ may