How to Grow Dahlias in Pots
Select a variety of dahlia suited for container growing., Pick out a large pot., Choose a heavy pot., Drill additional drainage holes., Clean the pot., Pick out a coarse potting mix., Plant the tubers before the roots start to grow too long., Start...
Step-by-Step Guide
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Step 1: Select a variety of dahlia suited for container growing.
Dwarf and low-growing varieties work best, but nearly any type can be grown if you have a large enough pot. -
Step 2: Pick out a large pot.
A good container to start with should be approximately 12 inches (30.5 cm) deep by 12 inches (30.5 cm) in diameter.
Larger varieties may need even larger containers, however, especially if the flowers exceed 3 feet (0.91 m) in height. , A light pot may not be sturdy enough, and the dahlia could become top heavy as a result. , This step may not be necessary if the container you use already has several large drainage holes that allow excess moisture to drain quickly.
If your pot has small holes or only has one center hole, you may need to drill a few extra holes to improve drainage. , A dirty pot could spread disease, and hidden insect eggs may be lying in wait at the bottom of the pot.
Remove these threats by cleaning the container before you plant.
Simple soap and water will usually do the trick. , Standard potting soil alone is too porous and may lead to pour bud formation.
A good potting mix includes both potting soil and garden soil, or potting soil and compost.
Alternatively, non-soil mixes made of fine bark, peat, and various minerals may also work. , Long roots will become entangled, and separating the roots will damage them.
If the tubers need to spend time forming new roots, the flower's upward growth and bloom will be delayed and may be minimized for the season. , If starting the dahlias in pots that sit outdoors, wait until mid-April through all of May.
If starting the flowers indoors, you can plant the tubers in early April. , Filters wick away moisture, preventing the roots from drowning.
Placing gravel at the bottom of your pot will accomplish the same task, but a dahlia's roots need all the space they can get to grow, and the coffee filter method takes up much less room than gravel would.
Placing filters over the holes may also prevent bugs from getting in. , Do not pack it tightly; allow the soil to remain loose.
If using a pot deeper than 12 inches, you may need to fill it with more soil.
When all is said and done, dahlias need to be planted about 6 inches deep, and there should be an inch between the surface of the soil and the rim of the pot at the end of the potting process. , Make it damp, but do not soak. , Dahlias require a lot of nutrients to thrive.
Fish or seaweed fertilizer can provide additional micro nutrients, as well.
You can also purchase a copolymer slurry from a gardening store instead of using bone meal and fertilizer.
Follow the package for usage directions.
If mixing the slurry, fertilizer, or bone meal into the soil causes the coffee filters to move from the bottom of the pot, remove the soil from the pot and mix the elements together that way.
Simply add it back in, over the repositioned filters, once everything is combined. , Lay it down horizontally and leave at least 1/4 inch space between the root end of the tuber and the side of the pot.
If an eye has already developed, center the eye in the middle of the pot and allow it to face upward.
The sprout will come through from this eye. , Do not bury the tuber at this time, however.
Instead, cover it with a minimal amount of soil so that you may monitor its growth. , Lightly spritz the exposed surface of the tuber with just enough warm water to moisten the surface. , Do so carefully to avoid damaging the stalk, since the stalk is still fairly fragile at this stage.
Never cover the top set of leaves.
Continue adding soil until only an inch of empty space remains between the top of the soil and the rim of the pot. , Large dahlia varieties need extra support to prevent the stalks from breaking off.
Use a four foot stake with most varieties.
Metal works best due to its sturdiness.
The base of the stake should touch the bottom of the pot, and the stake itself should be firmly held in place by the soil and/or wires tied to holes drilled into the sides of the pot. , Give them a thorough watering two or three times a week.
Dahlias growing in hot, dry climates may need daily watering.
Never allow the soil to get soggy, however. , Dahlias grow best with six to eight hours of direct sunlight. , Many indoor dahlias do not receive enough light from the sun, and a plant light may be necessary to spur proper growth.
Set the light about six inches above the top rim of the pot for newly planted tubers and raise the light as the plants grow. , Use a low nitrogen fertilizer, and avoiding over-feeding. , The removal of these leaves improves air circulation, which reduces the risk of mildew. , Dahlias are subject to attacks from mold, earwigs, slugs, spider mites, aphids, and cucumber beetles. -
Step 3: Choose a heavy pot.
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Step 4: Drill additional drainage holes.
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Step 5: Clean the pot.
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Step 6: Pick out a coarse potting mix.
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Step 7: Plant the tubers before the roots start to grow too long.
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Step 8: Start sometime in April or May.
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Step 9: Place one or two biodegradable coffee filters over the holes in the bottom of your pot.
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Step 10: Fill your container a third way full with your potting mix.
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Step 11: Moisten the soil.
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Step 12: Mix a handful of bone meal and fertilizer into the soil.
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Step 13: Plant the tuber in the soil.
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Step 14: Cover the dahlia tuber with pre-moistened soil.
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Step 15: Allow any exposed eyes to remain above the soil.
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Step 16: Add more soil as the stalk grows.
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Step 17: Insert a stake into the pot
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Step 18: and tie the stalk to the stake.
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Step 19: Water the tubers deeply once the stalk extends above the rim of the pot.
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Step 20: Place the pot in full sun.
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Step 21: Supplement sunlight with fluorescent plant lights if started indoors.
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Step 22: Fertilize the flowers once every two weeks from June through September.
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Step 23: Remove bottom leaves late in the season
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Step 24: usually around mid-July.
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Step 25: Spray your dahlia with fungicide or insecticide as needed.
Detailed Guide
Dwarf and low-growing varieties work best, but nearly any type can be grown if you have a large enough pot.
A good container to start with should be approximately 12 inches (30.5 cm) deep by 12 inches (30.5 cm) in diameter.
Larger varieties may need even larger containers, however, especially if the flowers exceed 3 feet (0.91 m) in height. , A light pot may not be sturdy enough, and the dahlia could become top heavy as a result. , This step may not be necessary if the container you use already has several large drainage holes that allow excess moisture to drain quickly.
If your pot has small holes or only has one center hole, you may need to drill a few extra holes to improve drainage. , A dirty pot could spread disease, and hidden insect eggs may be lying in wait at the bottom of the pot.
Remove these threats by cleaning the container before you plant.
Simple soap and water will usually do the trick. , Standard potting soil alone is too porous and may lead to pour bud formation.
A good potting mix includes both potting soil and garden soil, or potting soil and compost.
Alternatively, non-soil mixes made of fine bark, peat, and various minerals may also work. , Long roots will become entangled, and separating the roots will damage them.
If the tubers need to spend time forming new roots, the flower's upward growth and bloom will be delayed and may be minimized for the season. , If starting the dahlias in pots that sit outdoors, wait until mid-April through all of May.
If starting the flowers indoors, you can plant the tubers in early April. , Filters wick away moisture, preventing the roots from drowning.
Placing gravel at the bottom of your pot will accomplish the same task, but a dahlia's roots need all the space they can get to grow, and the coffee filter method takes up much less room than gravel would.
Placing filters over the holes may also prevent bugs from getting in. , Do not pack it tightly; allow the soil to remain loose.
If using a pot deeper than 12 inches, you may need to fill it with more soil.
When all is said and done, dahlias need to be planted about 6 inches deep, and there should be an inch between the surface of the soil and the rim of the pot at the end of the potting process. , Make it damp, but do not soak. , Dahlias require a lot of nutrients to thrive.
Fish or seaweed fertilizer can provide additional micro nutrients, as well.
You can also purchase a copolymer slurry from a gardening store instead of using bone meal and fertilizer.
Follow the package for usage directions.
If mixing the slurry, fertilizer, or bone meal into the soil causes the coffee filters to move from the bottom of the pot, remove the soil from the pot and mix the elements together that way.
Simply add it back in, over the repositioned filters, once everything is combined. , Lay it down horizontally and leave at least 1/4 inch space between the root end of the tuber and the side of the pot.
If an eye has already developed, center the eye in the middle of the pot and allow it to face upward.
The sprout will come through from this eye. , Do not bury the tuber at this time, however.
Instead, cover it with a minimal amount of soil so that you may monitor its growth. , Lightly spritz the exposed surface of the tuber with just enough warm water to moisten the surface. , Do so carefully to avoid damaging the stalk, since the stalk is still fairly fragile at this stage.
Never cover the top set of leaves.
Continue adding soil until only an inch of empty space remains between the top of the soil and the rim of the pot. , Large dahlia varieties need extra support to prevent the stalks from breaking off.
Use a four foot stake with most varieties.
Metal works best due to its sturdiness.
The base of the stake should touch the bottom of the pot, and the stake itself should be firmly held in place by the soil and/or wires tied to holes drilled into the sides of the pot. , Give them a thorough watering two or three times a week.
Dahlias growing in hot, dry climates may need daily watering.
Never allow the soil to get soggy, however. , Dahlias grow best with six to eight hours of direct sunlight. , Many indoor dahlias do not receive enough light from the sun, and a plant light may be necessary to spur proper growth.
Set the light about six inches above the top rim of the pot for newly planted tubers and raise the light as the plants grow. , Use a low nitrogen fertilizer, and avoiding over-feeding. , The removal of these leaves improves air circulation, which reduces the risk of mildew. , Dahlias are subject to attacks from mold, earwigs, slugs, spider mites, aphids, and cucumber beetles.
About the Author
Stephanie Bishop
Experienced content creator specializing in crafts guides and tutorials.
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