HOW TO GROW DAHLIAS
HOW TO GROW DAHLIAS
Planting and Soil Preparation
Growing Dahlias is a truly rewarding experience! Dahlias are relatively easy to grow, and the blooms are sure to please.
Dahlia Tubers can be planted from Mid-April until Early June, depending on your location and your climate. Dahlias love to be in a sunny location— an area that receives at least 6-8 hours of direct sunlight is preferred. Dahlias will also grow in shady areas but generally will be taller and require more staking and care.
Dahlias love to be in the dirt. The dirt is a friend to Dahlia Tubers. They prefer loosened and well drained soil. If you have clay or thick/heavy soil, loosen it well, and you can add sand or peat to help with drainage. Dahlias do not like mulch or store-bought garden soil, as many of these products can possibly harm the tubers. Once soil is loosened and dry and about 12-15 C (55-60F) you are ready to plant! Plant your tubers about 10-15cm (4-5in) deep. Space plants between 45-60cm (1.5-2ft) apart. Do not water your tubers after planting—wait until the sprouts appear, unless you are in extremely hot and dry conditions in which case you may water them immediately. Otherwise, the rain will generally be enough.
If you wish to grow your dahlias in containers be sure to use large ones. Potted dahlias will require more care, more staking, more water and more fertilizer.
Caring for your Dahlias
After 4 weeks you should begin to see dahlia shoots. Staking dahlias will allow for a straighter, more beautiful plant that can withstand winds and heavy rains. You can stake with tomato cages or wooden stakes with string or twine. There are a variety of ways to stake dahlias, just take care not to drive the stake into the tubers. As dahlias become established, regular watering and fertilizing will help them grow, bloom vigorously and continue to put on a show until frost!
Dahlias respond well to fertilizer, but they don’t need too much Nitrogen. A 5-10-10 fertilizer blend is best, or any blend where the nitrogen content is about half of the potassium and phosphorous content. Too much Nitrogen will lead to lots of green growth and less blooms. Apply fertilizer monthly—beginning when sprouts appear and continuing once a month until the end of August. Follow each fertilizing with a heavy, deep watering. During dry, hot weather dahlias should be given a deep watering at least twice a week.
Weeds and Other Pests
Dahlias need to be weeded the old-fashioned way…by hand. Herbicide will kill your dahlias! Some bugs/insects feed on dahlias. Snails and Slugs can be the biggest bother to your plants. It is wise to bait them beginning at planting time and, continually, all season long. For other pests, please use care if applying insecticide soap or any chemicals. Be sure to follow all local rules and regulations. Mildew will attack some varieties in the late summer and into the fall. Some years, there will be more pests than others—this is Nature.
To Pinch or Not to Pinch/To Top or Not to Top
Either way is fine. Pinching will give you a shorter/bushier plant and if you choose to pinch them back, it should be done when plants are just under 60cm (2ft) tall.
Cutting Flowers
Enjoy the flowers during the prime season of August/September. If you are cutting the flowers, the best time to do so is in the morning while it is cooler outside. Be sure to remove old blooms from your plant to keep it growing and blooming all season!
Frost and Digging Tubers
In the fall, the frost will inevitably come and end your dahlia season. In Northern Climates, you need to dig your tubers up after the first killer frost. The best thing to do is wait for a killing frost and then cut your plants back a few inches above the ground and dispose of all the plant material. Wait at least one week to begin digging the tubers. Gently lift the Tubers with a spade or digging fork. Some will have grown bigger than others (this is normal); each variety is a unique plant and has its own characteristics.
Storage and Dividing Tubers
Ideal temperatures for winter tuber storage are 7-10 C (45-50 F) with a humidity between 65-75%. If they freeze, they will rot and if they are kept too warm, they will shrivel. There are a variety of ways to store tubers. Some people leave the dirt on them, others wash and dry the tubers thoroughly and store in peat or wood shavings.
Tubers can be divided anytime in the winter or the spring. It works well to wait until you can see the eyes, especially if you wish to divide them into single tubers.
Happy Gardening!
There are so many ways to enjoy your dahlias: bringing a bouquet to a friend, spending your time in the garden, showing your flowers at a fall fair or dahlia show. There are many great resources available online or in print to help you make the most of your dahlia garden. The American Dahlia Society has local chapters across North America as well. More info about the Society can be found at www.dahlia.org. The organization and its members have a wealth of information about dahlias! You are also welcome to email us at anytime with any questions.
