Caring for Cuttings
Benefits of Cuttings: Dahlia cuttings are the exact replica of the mother plant. Given the proper care and nutrition, it will grow the same as a tuber and produce an ample tuber clump by season’s end. There are a few benefits cuttings have over tubers. First, they are less prone to rotting after planting. Cuttings have a root system by the time you receive them which takes away the likelihood of a tuber rotting in the dirt. The worry of overwatering is not an issue with cuttings as they have an established root system to absorb water. Cuttings often produce blooms sooner than tubers. By the time you receive a cutting, it will be 6-8 weeks old. Depending on when you typically plant your tubers, this could give you a substantial jump start. Most often, people buy cuttings because the dahlia variety is new and/or hard to acquire a tuber. Cuttings give wider access of those hard to find dahlias.
Negatives of Cuttings: There is a learning curve when it comes to successfully growing cuttings that are shipped. While most times cuttings survive shipping just fine, it is easy to forget they just traveled days through all different temperatures while being thrown around in a package, without any light. Even the healthiest of cuttings need a smooth transition back to air, light and water after shipping. Even though cuttings have been hardened off in my climate, that is vastly different than your humidity, wind and UV exposure. It is VERY important to slowly acclimate your baby cuttings to their new home.
I have outlined my process of receiving cuttings via mail that has worked well for me year after year. If you follow these guidelines, you will give your new cutting the time and care it needs to become a beautiful plant for you.
Introducing water: Your cutting needs water as soon as you take it out of the clamshell. I like to soak the bottom of root cube in about a half inch of water for at least 15 minutes. A cup from your kitchen works well for this.
Damaged Leaves: Rarely, the leaves touching the edges of the clamshell container may get black spots on them from excess moisture during shipping. Simply snip those leaves off the cutting and the plant will push new growth.
Root System: I use Root Riot rooting cubes with all my cuttings. They are made of a peat mixture that holds form and moisture, protecting the roots during transit. Root Riot cubes do not need to be removed before planting. If you would like, you may plant the entire Root Riot cube in the ground, and it will grow a beautiful plant for you. However, I like to remove my Root Riot cubes before planting if the root system will allow. If it is a variety with ample amounts of thin roots, I leave them alone as removing the cube will do damage to the already established root system. If the variety has only a few big, thick roots I will always gently remove the rooting cubes before planting. If you choose to remove your Root Riot cubes, make sure you are confident in doing so. Any damage to the cutting due to removal of rooting cubes is solely your responsibility.
Growing indoors until it is safe to plant outside: If you receive your cuttings before the last frost date for your area, be prepared to grow them inside until there is no threat of frost. Dahlias aren’t meant to be indoor plants; doing so requires grow lights and additional care. If you choose to get early, be prepared for the extra work of keeping dahlias healthy indoors. Light is very important. Make sure you have grow lights accessible and ready. Indirect window light is not substantial enough to grow dahlias indoors for long periods of time. You need adequate air flow for your new cuttings. If the air is stagnant or the cuttings are in a place that has consistent high humidity, the leaves of your cuttings will start showing signs of powdery mildew. This is very common if not treated preventatively. Copper fungicide spray works well for both prevention and treatment once visible. I treat my cuttings biweekly. You can find the brand I use here along with my favorite supplies for growing dahlias.
Rest after shipping: Trust me, I know the excitement of getting new cuttings. But, your cutting needs time to make the transition from my place to yours. This takes time. As hard as that is to wait, I recommend giving your cuttings 2 days rest before disturbing the root system, potting into a larger pot or transitioning to the outside elements. While they are in these first 2 days, make sure they have access to water and the appropriate amount of light (See below under “Introducing Light”). I use these little cups during this rest period, but any small kitchen cup will do as long as it holds the cutting upright.
Introducing light: This is the most important aspect of acclimating your new cuttings. DO NOT put your cutting in direct sunlight. If you plant them directly outside without the proper hardening off, they will surely die. My cuttings are under grow lights 12 hours per day. I do not use heating mats. Being in the dark for 2 days during transit will make the cuttings sensitive to light. To avoid damage and undue stress for your new cuttings, only expose them to 6 hours of grow lights the first day of arrival. After the first day your cuttings will thrive under 12 hours of grow lights per day until you are ready to harden them off and plant outside according to your last frost date.
Potting Up: I include Mykos Pure Mycorrhizal Inoculant with every cutting. Sprinkle liberally on the visible roots before planting in dirt. Don’t stress over this part; you can’t use too much. This helps the roots absorb nutrients from the soil and gives your cutting a jump start to a healthy season. I highly recommend removing the bottom 2 sets of leaves and planting your cutting deep; doing so increases the likelihood of tuber production for fall harvest. There are many tutorials you can find online on this topic. Make sure to water in your newly planted cutting thoroughly.
Hardening Off: Pay attention here, because skipping this step will lead you straight to cuttings dying off. If your climate is safe to plant outside, make sure you still give the cutting 2 days with indirect light from a window inside before starting to slowly acclimate them to UV straight from the sun. Start slow with 2-3 hours of shade then acclimate over the course of a week adding an hour or two per day. Transition from shade to filtered sun, ending with your plants able to be in full sun and breeze. There is a ton of information online about hardening off plants. This process isn’t fast and should take at least 6-7 days. Some dahlia varieties do better during hardening off than others. When in doubt, take it slow and watch your leaves. If they start to droop in the sun or breeze, bring them inside and start the process again the next day.
Here is a sample of what I do with my own cuttings.
Day 1: Receive Cutting in the mail, provide water and limited indoor light.
Day 2: Increase light to cutting a make sure it has adequate water.
Day 3: Apply Mykos, pot up in a 4 inch pot. Water thoroughly. Continue appropriate light.
Day 4: Place outside for 2 hours in a shady area protected from the breeze.
Day 5: Place outside for 3 hours in a shady area protected from the breeze.
Day 6: Place outside for 4 hours in a filtered sunny area with moderate breeze.
Day 7: Place outside for 5 hours in a filtered sunny area with moderate breeze.
Day 8: Place outside for 5 hours in a mostly sunny area with little protection from breeze.
Day 9: Place outside in full sun.
Every climate is different with weather changing constantly. Use your best judgement for your area. This is what I have found works well for me and my climate. Watch your cuttings carefully during hardening off. Once your cutting is acclimated to your outdoor climate, you are good to plant outside in full sun.
