Caring For Your Plants
Dahlias
 Dahlias like to grow in a location that is protected from wind and in full sun.
They will benefit from shade in mid-afternoon. The soil should be fertile and well drained.
Adding peat moss or compost and deep digging in the fall helps to prepare a good bed.
In shorter growing seasons, tubers should be started indoors. Place the tubers in shallow
trays with drainage holes and cover with slightly damp peat moss and place in a warm location.
Do not cover the crown of the tubers with soil. Keep slightly damp until the sprouts emerge.
The tubers can then be placed in individual 5 – 6 inch pots filled with a good potting medium
and placed in good light. The early sprouts can be used to make cuttings, other wise,
leave only the strongest sprout to grow especially in the larger varieties.
Poms and miniatures can be an exception.
Plant as soon as the soil is warm and the danger of hard frost is over.
Make sure that the soil is well dug. Place sturdy stakes where the plants are to grow.
Tubers should be planted in rows 3 feet apart and 2 to 3 feet apart in the rows.
Small varieties may be planted closer. Dig a hole about 6 inches deep and add
well-rotted manure, compost or bone meal below the tuber. The bottom leaves may be
removed and the tuber planted with the neck of the tuber towards the stake about 4-5 inches
deep. Dormant tubers should be planted flat with the neck close to the stake.
If the soil is dry, water slightly. Too much and the tubers can rot if the soil is cold.
Collars should be placed around the shoots to keep away cutworms. Keep a few pots of
dahlias available to replace plants that do not grow well. They can be later be used
for pot roots if not used in the garden.
Dahlias have shallow roots, so the soil should not be worked deeper than several inches.
Watering should be about every 2 weeks, oftener if the weather is hot and dry.
A good thorough soaking is best. Mulching helps to conserve moisture and control soil
temperatures. Plants may also be hilled with soil to give additional support.
Dahlias are heavy feeders. Use a low nitrogen or a balanced time release fertilizer
spread about 12 inches away from the stalk to start and work into the soil.
As buds start to develop you can use a low nitrogen water-soluble fertilizer such as
Phostrogen 10-10-27 to promote flower and tuber development. Do not over fertilize with
nitrogen after mid August. Miracle Grow formulations such as 15-30-15 contain too much
nitrogen for summer and fall use.
Keep an eye out for aphids and other insects. Control should start before the first bud
stage or as soon as the insects are evident. Use a systemic such as Cygon 2E or use
Diazinon or Malathion every 2 weeks to control aphids and thrips. Tarnished plant bugs
can be a nuisance during the blooming season. A spray such as Kelthane may be used to
control spider mites during hot weather. An insecticidal soap can be used as an
alternative to chemical control.
Lateral growth and more flowers can be encouraged by carefully pinching out the center
growing tip after about the 3- 4th set of leaves depending on the variety. This will
encourage new laterals to grow. Larger blooms for display can be developed by pinching
out the side buds at the end of the growing branches to favor the centre bud left to grow.
It takes about 30 days from a pea size bud until bloom. Make sure that you tie up the
dahlias to the stakes as they grow to prevent breakage during strong winds. Plants can
become very large, up to 6 feet in height.
Enjoy your dahlias. Cut them during early morning or late evening. Place them
immediately in a container of warm water. Remove spent blooms from the plants
and cut back to a lower leaf node to encourage more bloom.
Tubers should be dug after a hard killing frost. Cut the tops off at about 6 inches and
leave in the ground for about a week to allow the eyes to develop on the stem for easier
dividing later on. Lift the roots carefully by digging all around the clump with a digging
fork and carefully lifting the clump so as not to break too many tubers. Wash the clump
and store in a cool place for about a week to cure the tubers. Place upside down so that
no water remains in the hollow stems. Avoid excessive drying of the clumps by misting them
occasionally before dividing them. Clumps may then be divided into individual tubers.
Each tuber must have an eye to grow. The eyes are found only around the base of the crown.
All cut surfaces should be allowed to dry and then dipped in sulfur. Tubers can be stored
in boxes of vermiculite or peat moss. A new method is to take a number of tubers, roll
them up individually into a clump in saran wrap and tape shut. They can then be stored
in boxes. Store in a cool dark room at 40 – 45F, Check your tubers several times during
the winter for drying or rot. Remove rotten tubers as they will spoil the whole package.
Dry tubers can be sprayed to re-hydrate them.
John Rempel
Used with permission
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