How to Graft a Cactus and Care

Grafting is a popular gardening technique of joining two different plants together to grow as one. It is commonly done to improve a plant’s growth rate, hardiness, and resistance to pests and diseases. Cactus grafting can be delicate but may be done for an important course.

For example, a grower might graft a moon cactus onto a fast-growing rootstock (Hylocereus) to enhance their survival. Moon cacti are known for their slow growth, albinism, and inability to produce their own food due to a lack of chlorophyll. 

How to graft a cactus

Cactus grafting is a relatively simple procedure, but you need to follow the steps carefully for the project to be successful. The best time to graft a cactus is during the spring or summer when the cacti are actively growing. Grafting during the winter, when the cacti are dormant is less likely to be successful.

To graft a cactus, you will need the following items:

• A sharp knife or shears
• A grafting paste or wax
• Two cacti of similar size and shape
• A pot with drainage holes 
• A well-draining potting mix
• A pair of gardening gloves

Cactus grafting instructions

1. Choose two cacti plants that are of almost similar size and shape. The cacti should be free of pests and diseases. 
2. Cut a 1-inch slice from the top of one of the cacti to obtain the scion and make a 1-inch slice on the top of the other cactus, which will be the rootstock. Be sure to use a sterilized sharp knife or shears to make clean cuts.
3. Carefully fit the scion onto the rootstock so that the cambium layers of both cacti are aligned. This will ensure water and nutrients are transported without any problem between the top and bottom of the plant.
4. Apply grafting paste or wax to the wound to seal it. Cactus wound is highly prone to rot and infections and sealing them will prevent the entry of water or bacteria and fungi.
5. Plant the grafted cactus in a pot that is just slightly larger than the cactus. Make sure to use a well-draining potting mix and a pot with drainage holes.
6. Water the cactus well until the water gets out through the pot drainage holes. Be sure not to splash water on the wounded section.
7. Place the cactus in a location with bright, indirect sunlight. This should be near the east or south-facing window or under a shade outdoors.
8. The cactus should heal in 4-6 weeks. So be patient and keep monitoring the plant for any issues.

Grafted cactus care

Grafted cacti require a little bit more care than non-grafted cacti. Here are some tips for caring for your grafted cactus:

Watering

Water your grafted cacti less frequently. Allow the soil to dry out completely between waterings. Overwatering and poor drainage can cause the problem of root rot. This is where cactus roots die and rot when they fail to get sufficient air supply.

Sunlight

A grafted cactus needs bright, indirect sunlight. Avoid placing it in direct sunlight, as this can scorch the stems. Cactus sunburn can be fatal for grafted cacti. You may also place the plant under grow lights if the location is not receiving enough sunlight.

Fertilizer

While most cacti don’t need to be fed regularly, a grafted cactus should be fertilized every four weeks with a balanced cactus fertilizer. Be sure to dilute and use the fertilizer as directed on the product label to avoid overfertilizing.

Temperature

Cacti prefer warm temperatures around 70°-80°F during the growth season. The humidity should range between 40%-60%. Avoid placing your grafted cactus in cold drafts or near heating vents. 

Pests and diseases

Like any other succulents, cacti are susceptible to pests and diseases when grown under poor conditions. Monitor your grafted cactus for insect pests such as mealybugs, scale, and spider mites or diseases and treat them promptly. You may use insecticidal soap or neem oil to manage most of the pests.

Best rootstock for grafting cactus

When choosing a rootstock for grafting a cactus, important factors to consider include the growth rate of the rootstock, its resistance to pests and diseases, and its ability to support the weight of the scion. Some popular rootstocks for grafting cacti include:

Hylocereus undatus: Also called dragon fruit plant, this cactus is a fast grower and is resistant to pests and diseases. It is a good choice for grafting cacti that are slow-growing or that are susceptible to pests and diseases.

Pereskiopsis spathulata: This cactus is a very fast grower and is a good choice for grafting cacti. It roots rapidly and can withstand both frequent and infrequent watering. However, it is not as resistant to pests and diseases as some other rootstocks.

Opuntia fragilis: This cactus is a good choice for grafting cacti that you want to grow outdoors in areas with cold winters. It is a hardy cactus that is resistant to colds, pests, and diseases.

Can you separate a grafted cactus

You can separate a grafted cactus especially when you want to save it from a dying scion or rootstock due to incompatibility issues. However, it is important to do so carefully to avoid damaging the cacti. 

Here are the steps on how to separate a grafted cactus:

1. Use a sharp knife or shears to make a clean cut through the rootstock.
2. Carefully remove the scion from the rootstock.
3. Let the cutting dry out for almost a week to prevent infection.
4. Plant the scion in a new pot with well-draining soil.
5. Water the scion well and place it in a bright, indirect sunlight location.
6. The scion may take a few weeks to root and adjust to the new home. Be patient and once it has been established, you can care for it as you would any other cactus.

If the grafted cacti have grown together for a long time, it may be impossible to separate them without causing damage. If you are unsure whether or not you can separate your grafted cactus, it is best to consult with a professional horticulturist.

Final Thought

Grafting can help to improve the growth rate of cacti, their hardiness, and their resistance to pests and diseases. While it’s a simple process, it can be delicate and time-consuming. Not all grafting projects are successful unless you do it carefully as directed in this guide.

References

The Double-Cut Techniques for Grafting Cacti to Trichocereus pachanoi Rootstock; Bach and Dan – University of Arizona

Does Grafting Time Affect the Cactus Performance? Neda Bayat1*, Roohangiz Naderi2 and Ardeshir Rahimi Maidani3 – University of Tehran, Karaj, IRAN

A History of Grafting; Ken Mudge – Department of Horticulture Cornell University