THE GREATER ST. LOUIS DAHLIA SOCIETY |
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Mid-Summer Maintenance Tips:
The dahlia is a sturdy plant but it is also a sensitive plant that reacts to many things during the growing season.
When might that be, you ask?
Early morning, late evening, cloudy cool days and days of moderate to low humidity are some of the times.
The type of maintenance should coincide with current weather conditions and impending weather forecasts.
The bottom line is feeling confident and comfortable in what you do. There is nothing wrong with trying
something new but maintenance experimentation can prove costly. Always be aware of that. And whatever
experimentation you decide, do it on a plant that you are not heavily counting on.
At this time of year, maintenance falls into three general categories - pinching and tying, watering and feeding
and spraying and dusting.
PINCHING AND TYING: Pinching the center stimulates lateral growth which turns a potential corn stock into a
bushy plant capable of producing many usable blooms. Even such a bushy plant will grow to shoulder height
and that requires tying the main stock as well as each maturing lateral. Tying also makes it easier to perform
the other forms of maintenance.
WATERING AND FEEDING: Dahlia plants have the capacity to survive periods of heavy moisture but such
periods can be costly. Therefore, maintaining ample drainage is crucial throughout the entire growing season.
The amount of water needed during the growing season becomes greater as a plant reaches maturity and
begins to flower. Early on, a lesser amount of water actually helps stimulate root growth. And this is vital once
those hot, humid days appear.
Feeding (fertilization) is necessary but always bear this in mind: a dahlia plant will only take up what it needs.
So have an understanding of what you hope to accomplish before going overboard with fertilization. There are
two schools of thought when it comes to the application of nitrogen. One urges a lower concentration in
comparison to phosphate and potash. The other encourages a greater degree of nitrogen, while maintaining
required levels of phosphate and potash. Neither is completely right or totally wrong.
This is an area where experimentation can be done but an ample amount of record keeping also will be
required.
SPRAYING AND DUSTING: These procedures require the most care. Miticides and insecticides can be
personally harmful if proper precautions are not adhered to. First and foremost read the instructions carefully.
The dahlia is a sturdy plant but it is also a sensitive plant that reacts to many things during the growing season.
When might that be, you ask?
Early morning, late evening, cloudy cool days and days of moderate to low humidity are some of the times.
The type of maintenance should coincide with current weather conditions and impending weather forecasts.
The bottom line is feeling confident and comfortable in what you do. There is nothing wrong with trying
something new but maintenance experimentation can prove costly. Always be aware of that. And whatever
experimentation you decide, do it on a plant that you are not heavily counting on.
At this time of year, maintenance falls into three general categories - pinching and tying, watering and feeding
and spraying and dusting.
PINCHING AND TYING: Pinching the center stimulates lateral growth which turns a potential corn stock into a
bushy plant capable of producing many usable blooms. Even such a bushy plant will grow to shoulder height
and that requires tying the main stock as well as each maturing lateral. Tying also makes it easier to perform
the other forms of maintenance.
WATERING AND FEEDING: Dahlia plants have the capacity to survive periods of heavy moisture but such
periods can be costly. Therefore, maintaining ample drainage is crucial throughout the entire growing season.
The amount of water needed during the growing season becomes greater as a plant reaches maturity and
begins to flower. Early on, a lesser amount of water actually helps stimulate root growth. And this is vital once
those hot, humid days appear.
Feeding (fertilization) is necessary but always bear this in mind: a dahlia plant will only take up what it needs.
So have an understanding of what you hope to accomplish before going overboard with fertilization. There are
two schools of thought when it comes to the application of nitrogen. One urges a lower concentration in
comparison to phosphate and potash. The other encourages a greater degree of nitrogen, while maintaining
required levels of phosphate and potash. Neither is completely right or totally wrong.
This is an area where experimentation can be done but an ample amount of record keeping also will be
required.
SPRAYING AND DUSTING: These procedures require the most care. Miticides and insecticides can be
personally harmful if proper precautions are not adhered to. First and foremost read the instructions carefully.
First, let's turn our attention to root harvesting.
Root harvesting can take place before or after a killing frost. In either case, the old stocks should be cut down
about 8-10" above the ground. And if time allows, the root clump should remain in the ground for a few days.
This will stimulate the formation of new nodes that will eventually develop into the growth eyes in the spring.
Having the nodes form in the fall will also make it easier to divide the root clump, either upon harvesting or in
the spring. Extreme care should be exercised removing the root clump from the ground because the newly
developed roots are very tender and can be easily damaged making them unusable. Loosen the soil
completely around the clump with a spade fork and lift the clump out. DO NOT SHAKE THE EXCESS SOIL OFF
THE CLUMP. Remove what you can by hand and wash off the remaining soil with a hose.
Next remove the 8-10" stock by trimming it as close to the root clump as possible. Also trim off any small roots,
any damaged roots and the feeder ends on the larger, fleshy roots. Then turn the clump upside down to air
dry. In the shade. Avoid any surface that could extract moisture from the roots and cause them to get soft and
shrivel.
To guard against crown rot the exposed area of the old stock should be doused with powdered captan,
obtained from a garden store or sulfur , obtained from a drug store. To insure that your entire clump or
divisions can be identified come spring, they need to be marked with a magic marker by name or coded number.
Now, we turn to the equally important storage phase.
The harvested clumps or roots can be stored several different ways. I have found over time that the use of
coarse vermiculite in 5 gallon plastic buckets works well for me. They can be wrapped in damp paper or put in
plastic bags, using wood shavings or sawdust. Keeping the roots from drying out or freezing is key.
No one method is better than another. The quantity of clumps or divisions and your storage area will determine
in large part what method is used.
A dry area that stays between 45-50 degrees is ideal. If such conditions do not exist, then one's priorities
should be these: In an unheated garage, place your root container next to the warmest wall and wrap it with an
old blanket. If the storage area is in a heated basement, then place the container as far as possible from the
heat source. Otherwise, the roots will sprout prematurely.
Six weeks or so after storage it is a good idea to check the clumps and/or divisions. If they appear to be okay
then nothing else needs to be done until mid March. Then it is time to move the storage container into a heated
area to stimulate the formation of eyes. This process can take several weeks, depending on the variety.
Planting will follow once the threat of first frost is gone.
Fall garden maintenance.
Adding composted materials and old animal manure in the fall and tilling it in will make the soil that much better
in the spring. Composted materials can be your own or from a commercial source.
Composted material serves a double purpose. First it provides nutrients for future growing seasons. Second, it
helps loosen the soil and this is key because the looser the soil the easier it is for the tuberous dahlia roots to
grow and support healthy plants, which in turn yield show-quality blooms.
Fall is also a good time to do a soil test. The test will provide pH results and it measures the amount of usable
phosphorus and potash. Ample phosphorus is crucial for the development of quality blooms and ample potash
is required for healthy root development. A pH of 6.3-6.5 is what every top dahlia grower tries to attain and
maintain.
The fall allows time to begin fixing whatever deficiency one's soil might have. Remember, however, that fixing
one or more deficiencies must occur over a period of time. IT CANNOT BE ACCOMPLISHED IMMEDIATELY.
Also remember to avoid working in your patch when it is either to wet or to dry. Either will only produce hard
clumps of unmanageable soil, making your job that much more difficult later on or in the spring.
Fall really is the time to jump start whatever maintenance one might be planning in the spring.
The roots are resting, the soil is resting and now you can rest, too.
Root harvesting can take place before or after a killing frost. In either case, the old stocks should be cut down
about 8-10" above the ground. And if time allows, the root clump should remain in the ground for a few days.
This will stimulate the formation of new nodes that will eventually develop into the growth eyes in the spring.
Having the nodes form in the fall will also make it easier to divide the root clump, either upon harvesting or in
the spring. Extreme care should be exercised removing the root clump from the ground because the newly
developed roots are very tender and can be easily damaged making them unusable. Loosen the soil
completely around the clump with a spade fork and lift the clump out. DO NOT SHAKE THE EXCESS SOIL OFF
THE CLUMP. Remove what you can by hand and wash off the remaining soil with a hose.
Next remove the 8-10" stock by trimming it as close to the root clump as possible. Also trim off any small roots,
any damaged roots and the feeder ends on the larger, fleshy roots. Then turn the clump upside down to air
dry. In the shade. Avoid any surface that could extract moisture from the roots and cause them to get soft and
shrivel.
To guard against crown rot the exposed area of the old stock should be doused with powdered captan,
obtained from a garden store or sulfur , obtained from a drug store. To insure that your entire clump or
divisions can be identified come spring, they need to be marked with a magic marker by name or coded number.
Now, we turn to the equally important storage phase.
The harvested clumps or roots can be stored several different ways. I have found over time that the use of
coarse vermiculite in 5 gallon plastic buckets works well for me. They can be wrapped in damp paper or put in
plastic bags, using wood shavings or sawdust. Keeping the roots from drying out or freezing is key.
No one method is better than another. The quantity of clumps or divisions and your storage area will determine
in large part what method is used.
A dry area that stays between 45-50 degrees is ideal. If such conditions do not exist, then one's priorities
should be these: In an unheated garage, place your root container next to the warmest wall and wrap it with an
old blanket. If the storage area is in a heated basement, then place the container as far as possible from the
heat source. Otherwise, the roots will sprout prematurely.
Six weeks or so after storage it is a good idea to check the clumps and/or divisions. If they appear to be okay
then nothing else needs to be done until mid March. Then it is time to move the storage container into a heated
area to stimulate the formation of eyes. This process can take several weeks, depending on the variety.
Planting will follow once the threat of first frost is gone.
Fall garden maintenance.
Adding composted materials and old animal manure in the fall and tilling it in will make the soil that much better
in the spring. Composted materials can be your own or from a commercial source.
Composted material serves a double purpose. First it provides nutrients for future growing seasons. Second, it
helps loosen the soil and this is key because the looser the soil the easier it is for the tuberous dahlia roots to
grow and support healthy plants, which in turn yield show-quality blooms.
Fall is also a good time to do a soil test. The test will provide pH results and it measures the amount of usable
phosphorus and potash. Ample phosphorus is crucial for the development of quality blooms and ample potash
is required for healthy root development. A pH of 6.3-6.5 is what every top dahlia grower tries to attain and
maintain.
The fall allows time to begin fixing whatever deficiency one's soil might have. Remember, however, that fixing
one or more deficiencies must occur over a period of time. IT CANNOT BE ACCOMPLISHED IMMEDIATELY.
Also remember to avoid working in your patch when it is either to wet or to dry. Either will only produce hard
clumps of unmanageable soil, making your job that much more difficult later on or in the spring.
Fall really is the time to jump start whatever maintenance one might be planning in the spring.
The roots are resting, the soil is resting and now you can rest, too.
Spring and Getting Ready For Planting:
Removing whatever debris remains from last fall is
essential so if an extended period of wet weather occurs
the accompanying breezy wind can dry out the ground
quicker. Any additional compost material can be applied
at this time. Working it in the soil now, if possible, will be
more beneficial. But one must guard against tilling if the
ground is to wet. All that will be accomplished is turning
the ground into rock-hard clumps when it dries. And that
will make even more work later. If you determine that
your soil is either to acid (a low PH) or to alkaline (a high
PH) you can add (to lower the PH) iron sulphate or agri
sulphur at this time and work it into your soil.
Conversely, (to raise the PH) add lime. Each of these
things can be gotten at your local garden centers. Small
amounts should be added prior to planting and
additional amounts in the fall, once the season is over.
Amounts of composted material also will reduce the pH
of your soil. What you are trying to accomplish is a pH of
between 6.3-6.5. It is within this range that a dahlia plant
can extract the maximum amount of nutrients from the
soil. This also is a good time to inventory all the
insecticides and fertilizers that will be needed during the
growing season. If it has not been a prolonged or harsh
winter, this may lead to a heavier concentration of pests.
It also does not hurt to make a lay-out of your patch.
This can serve several purposes. First it will give you a
good idea how many plants your space will comfortably
support. And you may want to rearrange your scheme
from last year if one or more varieties did not do well in a
particular spot.
Removing whatever debris remains from last fall is
essential so if an extended period of wet weather occurs
the accompanying breezy wind can dry out the ground
quicker. Any additional compost material can be applied
at this time. Working it in the soil now, if possible, will be
more beneficial. But one must guard against tilling if the
ground is to wet. All that will be accomplished is turning
the ground into rock-hard clumps when it dries. And that
will make even more work later. If you determine that
your soil is either to acid (a low PH) or to alkaline (a high
PH) you can add (to lower the PH) iron sulphate or agri
sulphur at this time and work it into your soil.
Conversely, (to raise the PH) add lime. Each of these
things can be gotten at your local garden centers. Small
amounts should be added prior to planting and
additional amounts in the fall, once the season is over.
Amounts of composted material also will reduce the pH
of your soil. What you are trying to accomplish is a pH of
between 6.3-6.5. It is within this range that a dahlia plant
can extract the maximum amount of nutrients from the
soil. This also is a good time to inventory all the
insecticides and fertilizers that will be needed during the
growing season. If it has not been a prolonged or harsh
winter, this may lead to a heavier concentration of pests.
It also does not hurt to make a lay-out of your patch.
This can serve several purposes. First it will give you a
good idea how many plants your space will comfortably
support. And you may want to rearrange your scheme
from last year if one or more varieties did not do well in a
particular spot.
Getting an early start:
Whether you plan to start roots indoors soon for
propagation purposes or later for eventual
planting outdoors it is wise to keep these things
in mind.
Whether you plan to start roots indoors soon for
propagation purposes or later for eventual
planting outdoors it is wise to keep these things
in mind.
- Keep your potting soil damp but not wet and do
not let the soil become dry. - Refrain in the beginning from adding fertilizer
(osmocote) or (weak liquid solution) to your
potting soil. Although some commercial potting
soils already have osmocote in them. Once a
number of cuttings have been taken a shot of
weak fertilizer solution can be beneficial. - When choosing roots for propagation select
those of medium to small size. Large roots often
take a very long time to sprout and they tend to
rot much quicker than smaller roots because
they do not develop a feeder-root system. - Before placing the selected roots in a
propagation bench move them from your cooler
storage area to a warm area that will help
stimulate growth. The longer, the better. Ten
days to 2 weeks prior to starting would not be
overdoing it. - Placing propagation trays on heating pads can
be very beneficial. - Lights should be kept 6-8" above the
propagation trays in the beginning and raised
accordingly once the cuttings start coming.
Remember that the higher the lights the taller
the growth and this will result in spindly stems
that mayor may not produce healthy plants. - The rule of thumb for light exposure is usually
12-14 hrs per day. - Lastly, the number of cuttings taken from
anyone root usually will determine whether that
root can also be planted or destroyed. Use your
own judgment in that regard.
HELPFUL HINTS FOR FALL:
A dahlia season officially comes to a close once the root crop is harvested and stored and fall
maintenance is performed on your patch. These are two very important tasks. So here are a few
suggestions that hopefully will make each task a little easier .
A dahlia season officially comes to a close once the root crop is harvested and stored and fall
maintenance is performed on your patch. These are two very important tasks. So here are a few
suggestions that hopefully will make each task a little easier .