The freezing temperatures of winter months will kill dahlias.
If you live in an area that has a freezing winter season, then it is likely that the tubers of your dahlias will die or rot. However, if you live in a warm area during the winter months, then the dahlias may survive.
If you live in zones 8 through 10, then winter temperatures are mild enough for the dahlias to survive without much care or attention.
If you live in zone 7, and the winter temperatures do not drop below 20 degrees F, you can leave the tubers in the ground for the winter.
For dahlias growing in zones 3 through 6, the tubers should be dug up and stored in a warm location until they are replanted in spring.
Can You Leave Dahlias In The Ground Over Winter?
Dahlia flowers are beautiful blooms of many shapes and colors!
Homeowners have fallen for dahlias because they provide a captivating visual for a garden. Dahlias come with a variety of shapes and sizes, making them versatile for all sorts of garden designs.
When dahlia tubers experience cold weather, they’ll rot during the winter season if you do not accurately remove and store them.
If dahlia tubers are frozen, they will divide and wither away. The tubers must therefore remain well preserved throughout winter and should be replanted in the spring.
If they are improperly stored, there is a good chance that dahlia tubers will rot or dry out.
Because these types of flowering tubers are a significant investment in both capital and time, you must take care of them, particularly for the purposes of storing them accurately.
When the soil freezes, dahlia tubers are affected by their hardening. This means that freezing temperatures make it difficult for the tubers to properly establish themselves during winter.
If dahlia tubers are grown in a well-drained soil, the tubers will survive winter in the ground.
In summary, well-drained soils allow nutrients to migrate into tubers, and tubers are not harmed by frost because frost is unable to penetrate deeply into well-drained soils.
To Uproot or Not To Uproot The Dahlia Tubers
When growing dahlias, keep in mind that these plants do best at warm temperatures and do not do well when exposed to freezing temperatures.
When there is frost, the stems and flower will turn black.
The tubers are still alive although the plant appears dead and are still in a warm soil. Your decision to remove the tubers or not really depends on how cold your winter temperatures get.
Winter temperatures in USDA hardiness zones 8 to 10 do not get very cold and rarely get below 20° F.
In these zones, if you wish, you can leave your tubers in the ground until they sprout in spring. If you do this, you should prune the stems to a few inches above the ground and allow the bulbs to remain in the ground.
In order for the dahlia tubers to survive in zone 7, the soil must be well-drained, but adding a bit of mulch to the surface will help retain some heat.
If you want to be sure that your tubers don’t rot or die during the winter months, it is wise to store them inside at the proper temperatures.
Good luck! If you live in zones 3 to 6, then your dahlia tubers are not likely to survive through the winter. These zones regularly have freezing temperatures through winter.
For this reason, you will need to prune the stems and dig up the tubers and place them in a nursery pot until spring.”
When To Uproot The Dahlias
If you live in an area where freezing temperatures occur, you will need to dig up and protect your Dahlia tubers until spring. The best way to do this is to prepare ahead of time so that when the temperature dips below 32 degrees, your Dahlias do not get damaged by frost like all other flowers.
The first indication that it is time to dig up your Dahlias is when the weather turns to Fall (the first frost). This is also when most vegetation begins to turn brown and die.
The rings and stems of your Dahlias will be turning black as the cold air arrives. Also, they will have lost all of their color and have become very weak.
You must dig up your Dahlia tubers before the weather dips below 20°F or frost will kill the tubers.
How To Uproot And Store
The following procedure should be used to uproot and store your tubers safely:
- Mark all the plants to be stored so that the variety is tracked. The only plants you need to save are those that are healthy and show some degree of beauty to them and have to be fitted with proper equipment such as gloves or other protective clothing to avoid frostbite.
- After the first frost has hit, let the tubers lie in the ground for a week. Doing this strengthens them before winter storage. After a week cut off the flower stems 4 inches above the ground, leaving the labels at the same time.
- Using a shovel or garden fork carefully uproot the bulbs, paying special attention to dig about a foot away from the base of the bulbs, as they may reside anywhere from 4 up to 16 inches below ground level. Be as gentle with the tuber as possible to avoid damaging it or creating a cut which will create a breeding ground for rot.
- Let the tubers dry for 2 days after carefully removing them from the ground. While they are drying, do not allow them to dry in direct sunlight and do not expose them to frost. You can also subdivide some of the tubers now if you would like to plant more bulbs in the spring. Use a sharp knife to cut at the intersection of the bulbs.
- Wrap the tubers properly, so you do not damage them. For example, if they are planted in nursery pots, store them inside. If not, you are able to pack the tubers into either ventilated boxes or plastic bags, allowing for adequate airflow.
- Whenever packing your box or plastic bag with your garden pots, be sure to keep them in a cool place, approximately between 40-50 degrees Fahrenheit and keep in mind, frozen tubers will not sprout.
Precautions When Packing The Tubers
Storing the tubers can be relatively straightforward for those who already know how to go about it, but it’s also relatively challenging for everyone else. The most critical part of storing the tubers is avoiding storing them in wet conditions, as this can lead to the tuber rotting.
While many people can successfully store their tubers just by placing them in paper bags, you may find it much easier to pack them more carefully.
In order to properly store your tuber, fill a cardboard box with of sawdust, peat moss, or vermiculite.
You will also want to make sure the individual tubers are not touching each other to prevent them from being damaged, decaying, or rotting. If you live in a climate where you typically have ice on the ground, a warmed garage or warm area in your home would be an excellent place to store your tubers.
Continue to check on your tubers on a weekly or bi-weekly basis, making sure they don’t run out of moisture or get too wet. Also, plan to discard any moldy tubers, as these will rapidly spread throughout your remaining tubers.
When And How To Replant The Tubers
Springtime is when you should be replanting your tubers.
Do not replant directly outside as it can still be undesirable and the weather will not yet support them.
Place them into pots first and grow indoors for approximately 2 months prior to transplanting them into your garden.
Plant the tubers about 2 or 3 inches deep in the soil of the pot, ensuring that the soil stays moist but does not become wet as this will cause the tubers to rot. Also, keep the temperature of the soil above 65°F.
When digging your transplanting holes, dig a hole that is about 6 inches deep, as you will be placing the tubers 4 inches into the soil, and then filling the hole with soil up to the top of the tubers.
Only transplant your tubers after you have confirmed that no frost is present outdoors.
Dahlia tubers prefer and grow better in organic soils that drain well.
You can add organic fertilizer into the holes prior to planting the tubers, or if you don’t have organic fertilizer, you can use a small amount of DAP fertilizer. Make sure to water the tubers well so that the roots develop properly.
Once the tubers start to sprout, you need to provide enough sunlight for the plant and protect it from wind. Wind can damage the weak stems of the young plants.
Final Thoughts
Dahlias are a great choice for enhancing the beauty of your garden. Dahlias, if given the correct growing conditions, will provide you with lovely flowers throughout the entire growing season.
Most areas have a temperate/warm growing season; thus, dahlias are usually fairly easy to grow. They can survive during the entire growing season in temperate and warm seasonal temperatures.
Because of their delicate nature, dahlias will not survive harsh winter conditions. Therefore, those living in zone 3-6 should take care of their tubers during the winter months.
When tubers are stored, they should be placed in a climate-controlled environment; this will help the tubers produce dahlia plants once they have been planted in the spring.
If placed in the right environment to grow, dahlias are very easy to grow. Upon being planted in the spring, they will provide you with beautiful flowers to admire in your garden throughout the summer and fall months.