Grafting is a technique that combines two plants or parts of a plant so that they grow together. This allows you to combine the qualities of one strong, disease-resistant plant with those of another, usually one that produces good fruit or beautiful flowers. There are many methods of grafting, the ones described in this article should allow you to graft almost any seedling of vegetables or fruit, flowering shrubs and even some trees such as citrus fruits. For more information on how to proceed for larger branches or other tree types, read How to Graft a Tree
Steps
Understanding the Basics of Grafting
Step 1. You must understand the purpose of the graft
Fruit plants, including tomatoes and others sometimes considered vegetables, are reproduced and crossed for many generations to improve their characteristics. However, no strain is perfect. By removing part of a plant that produces beautiful fruit and grafting it into a strain that absorbs nutrients well and resists disease, you can create a hybrid that benefits from both.
- Since you are trying to combine certain characteristics, it makes no sense to graft two plants of the same variety. An exception is young fruit trees, which will produce fruit early if grafted.
- The hybrid plant will not produce seedlings with the same quality blend. The seeds are produced only from the top of the grafted portion.
Step 2. Purchase high quality seeds or rootstock plants
The rootstock is the plant that provides a root system and base. As these are carefully grown for certain qualities, they are usually more expensive than standard seeds, sometimes around 50 cents for any single seed. Choose a rootstock that has the qualities you are looking for.
- The generative rootstock it takes more energy to produce fruit, but is more vulnerable to disease, cold and heat. Use this type in mild climates and pick the small fruits as soon as they ripen.
- The vegetative rootstock it tends to be less fragile and tolerates heat better, but does not produce fruit quickly. It is ideal for the long and warm seasons.
- Choose a rootstock that is particularly disease resistant in your area if your plants have these problems.
Step 3. Select a variety compatible with the same species for fruit plants
The fruit-bearing plant, or scion, produces better fruit and its bud will be grafted into the rootstock. Look for your rootstock among the varieties that will thrive once grafted. If you run a farm or store, you should look for which scion will produce the type of fruit you seek.
Note: Most plants cannot be grafted onto a plant of a different species (e.g., a watermelon cannot grow on a tomato plant). Some plants can be grafted onto species linked to the same gene or family, but you should ask an expert or search online to find out if this is the case for your plants before giving it a try
Step 4. Use two plants of the same size
Grafting is best done if the rootstock variety (base) and the scion variety (bud) have the same size as the stem. Plant the rootstock and scion seeds in separate, labeled containers. If you know that one variety grows faster than the other, plant them at different times so that they reach graft time at the same time. The timing of grafting for each type is described below according to the methods.
Plant different seeds for each variety, as there is always a chance that some will not grow or survive the grafting process. If you want to grow different quantities of plants, you can use this online calculator to determine how many seeds you will need to plant
Step 5. Graft early in the morning or just after sunset
In these moments the plant usually moves the water from the roots to the leaves (transpiration) slowly, making it less vulnerable to the stress of grafting and consequent water loss. Ideally you should graft indoors or in a shady spot.
If you can only graft plants at other times of the day, move them to a shady corner early in the morning of the day you plan to graft
Step 6. Disinfect your tools to reduce the risk of infection
Since you will be making an open cut to the plant, you should keep your hands and tools clean to reduce the chance of an infection attacking the plant. Disinfect your cutting tools before starting. Scrub your hands with disinfectant soap and put on latex gloves.
Step 7. Treat newly grafted plants with great care
Newly grafted plants are most vulnerable to changes in temperature and infection, until the two plants are joined. For some types of grafting you will need a "recovery room" where you can monitor the environment carefully. The construction of the chamber is described in detail in the section of the nests. The other methods listed here do not require one.
Method 1 of 3: Grafting with Nesti (Tomato and Eggplant Plants)
Step 1. Build a recovery room in advance
A shelter room is needed to protect newly grafted plants as they heal. For one or two plants, a simple plastic bag to place on each plant after grafting is fine. For a large number of plants and a higher chance of survival, build or procure a large wooden or PVS structure, then cover it completely with a piece of polyethylene. Get a tarp or cloth to prevent much of the sunlight from entering the room during the first stage of healing. Place a bench to keep the plants.
Use a structure with a pointed roof so that condensation runs down the sides and does not drip onto the plants
Step 2. Add tubs of water to the chamber and check the environment
Place shallow tubs of water on the bedroom floor to increase the humidity. Before grafting plants, you should check the room environment for a few days to make sure it is stable. The temperature levels should be constant, between 21 and 27 ° C, while the humidity should be between 80 and 95%.
You shouldn't keep any other plants in this chamber until grafting is successful
Step 3. Choose plants that are between 5 and 13 cm tall and have the same diameter
Grafting is best done on young tomato and aubergine plants, whose stems are still green (herbaceous) and not woody. The stems should not be too thick, each plant is usually ready when it has 2-4 leaves. The most important thing to remember is that two plants should have the same size stems, so that they can grow together without difficulty.
- Note that the first and second leaves the plant will emit will be "seed leaves", not true leaves. They should be easily identified because they will have a different shape and size than true leaves, but the precise appearance depends on the species.
- If it is not possible to find stems of the exact same size, you should use a rootstock stem (base) that is larger than the scion stem (bud). The reverse would not work.
Step 4. Cut each plant in half, at a 45 ° angle
Use a sterilized razor blade or sharp knife to cut the stems of the rootstock (base plant) and scion (bud plant). While the exact cut angle is not important, you should adopt the exact same angle for each plant so that they fit together as closely as possible. Cut in one motion for the smoothest possible surface. Discard the top of the rootstock and the bottom of the scion.
- Cut each plant above the lowest “seed leaf”, but below the tallest and largest leaves, to prevent the scion from trying to grow roots, thus leading to an infection.
- See "Understanding the Basics of Grafting" for more information on rootstock and scion.
Step 5. Join the two plants with a graft tie
These ligatures should be silicone or rubber, they are available at nurseries or online. Try to match the corners of the cut surface as precisely as possible, then hold the plants together by closing the binding around.
Step 6. Immediately move the hybrid plant to a humid and dark environment
The plant must have time to grow the two vascular systems, allowing the lymph to flow. During this time, keep the plant in a humid, dark environment to minimize water loss from the scion.
The shelter room described above is perfect for this process, with a shade protecting it from the sun. For an easier operation, place a plastic bag on the plant and keep it out of direct sunlight. Water the base of the plant or steam the leaves if the ambient humidity is below 85%
Step 7. Gradually return the plant to sunlight
You should keep the plant in a protected environment for at least 4 days, often it will take a week for the leaves to be healthy and alive again. Even then, you should gradually vary the environment for other days, up to a week. Increase the amount of sunlight it receives gradually and reduce the humidity by occasionally eliminating a tub of water or lifting the plastic bag slightly.
Wilting is normal on the first day, vaporize the leaves if necessary. If the plant continues to wilt for three to four days, grafting has failed. While this method is very reliable, failure can happen 5% of the time even under the best of circumstances
Step 8. After two weeks, return the surviving plants to normal growing conditions
If the leaves of the plants are still wilted, it is unlikely that they will survive, or at the very least that they will be fine for that season. Healthy plants can be returned to normal growing conditions in order to be planted. Precise conditions vary by species.
Step 9. Plant the hybrid with the ligature well above the ground
The point where the two plants are joined should be at least 2.5cm above the ground to reduce the tendency of the top of the scion to grow roots. There is no need to remove the ligature, it should fall off by itself as the plant grows.
Don't hesitate to cut the roots that grow from the scion or the shoots that grow from the rootstock. You should also cut off the small branches, so that more energy goes into fruit production
Method 2 of 3: Split Grafting (Melon and Watermelon Plants)
Step 1. Plant the scion seeds 5-7 days earlier than the rootstock
As a general rule, the seeds of the scion, selected for its fruit, should be planted before those of the rootstock, selected for other qualities such as disease resistance. You can plant at very specific times if you know the growth rate of each variety.
Plant in small containers. For this method you need to join the two plants while each is still attached to its roots, so they must be able to reach each other without being transplanted
Step 2. Prepare the graft when both plants have their first true leaves
The first leaves that sprout are small seed leaves that do not look like the leaves of an adult plant. After a couple of leaves have grown, one will appear with an evidently different shape. When both plants reach this stage, they will be ready to be grafted.
You'll have a better chance of success if the stems of each plant are nearly the same diameter and height, although that's not that important for this method
Step 3. Use a razor blade to make a vertical cut on the rootstock
You should cut about half of the stem, vertically, at an angle between 30 ° and 60 °. Choose a point on the stem below the seed leaf.
Always use a disinfected razor blade and wear latex gloves. This will reduce the chance of an infection for the plant. Since cutting requires precision, a regular knife is not good for this method
Step 4. Make an upward cut to the stem of the scion, at an angle complementary to the other cut
Here, too, choose a point under the seed leaf and cut up to halfway through the stem. The cut should be at an upward angle so that the two cuts match.
Step 5. Join the two plants through the cuts and legal
Insert the cut part of the scion into the notch created by the cut on the rootstock. Unlike the grafted method, you don't need a specific tie to keep the two plants together, but you can use one. Otherwise, wrap the spot with plastic wrap, cling film or parafilm. A clear material will make it easier to see when the cut heals.
Labeling each plant right now is a great idea, especially if the varieties look alike. If you confuse them later, you may end up removing the best part of each plant instead of the worst
Step 6. Wait until the cuts have healed
Unlike the grafting method, you don't need to put the hybrid in a special chamber to heal, because each plant is still capable of carrying water from its roots to its leaves. Keeping them in species-appropriate conditions is still a good idea, especially if you have a large number of plants.
Step 7. Remove the top of the rootstock after about five days
If the plant looks healthy and isn't wilting, grafting has probably been successful. You should leave them together for a while, but if healing seems to have started, you can cut the top of the rootstock above the assemblage point.
Use a sterilized razor blade, as before
Step 8. Eliminate the roots of the scion a couple of days later
Check the health of the plant carefully. If the cut looks healed and the leaves are fresh and not wilted, you can cut the bottom of the scion, below the assemblage point. It is usually done within a week of grafting, but you can wait a few more days to be sure.
Step 9. Remove the ligature or plastic sheet
When the cuts have healed and you have successfully joined the two plants, you can discard the binding or plastic sheet that joined them. Continue to care for your hybrid like any other plant of the rootstock variety.
Method 3 of 3: Bud Grafting (Roses, Citrus, and Avocado Trees)
Step 1. Plant the rootstock early
Roses and plants of the same size should be planted about 30cm apart. Plant them in a greenhouse and nurture them according to the needs of the species and variety. They can be grown from seed or cuttings, but they will need to be planted early so that they have woody stems by the time the scion sprouts.
- Unlike other forms of grafting, which attach a portion to the main plant, bud grafting requires the scion to sprout. This means that the scion can be of a different age or size than the rootstock.
- See "Understanding the Basics of Grafting" to learn more about rootstock and scion.
Step 2. Prepare the plants for grafting in a cool climate when the scion is sprouting
If the weather is hot and dry, water the rootstock abundantly for two weeks before grafting. This helps the bark to be soft and easy to cut and manipulate.
Step 3. Make a T-shaped cut on the rootstock
The cut should be 20-30cm above the ground. The vertical portion of the T should be approximately 2.5-4cm, the horizontal portion should cover approximately 1/3 of the distance around the stem. There should be two flaps of bark, each on one side of the cut, which can be detached slightly from the trunk.
- Flowering roses and bushes can be 5-10cm above the ground.
- As always, when cutting the trunk or stem of the plant, it is a good idea to use a sharp, sterilized knife and wear latex gloves. This reduces the chances of plant infections.
Step 4. Cut a healthy shoot from the scion
Select a part of the scion that is strong and healthy and remove one sprout. Cut into the wood to remove a piece of wood starting 1.2cm below the shoot and ending about 1.9-2.5cm above it. Carefully remove this piece of wood, cutting it off the branch if necessary.
Step 5. Insert the wood with the sprout into the T-cut
Gently pull aside the wood flaps on either side of the T-cut to reveal the green part of the wood underneath, called the draft layer. Insert the piece of wood containing the sprout, pointing the sprout upwards. Slowly push it into the cut until the sprout is below the horizontal cut of the T.
Each piece should have a layer of green wood against the other. You may need to try a few times to trim the plants to the right height. A rootstock plant can receive several scion shoots
Step 6. Merge the plants
You can purchase special gardening material for this, called grafting rubber. Otherwise, use wide bands of rubber or green tape. Do not cover the shoot with the tie.
Step 7. Wait for it to heal before removing the wraps
Cuts will take 3 to 8 weeks to heal, depending on the season. When the plant looks healthy and the cuts have healed, remove the bands.
Step 8. Cut the part of the rootstock some distance from the shoot
You don't want the rootstock to grow other shoots, but don't remove it immediately. Cut the stem of the rootstock about 20-30cm above the shoot, or a few inches below if it is a small plant. This branch will help protect the vulnerable part where the two plants have been joined.
Step 9. Once the sprout has grown and put out new leaves, remove the rest of the rootstock
Once the inserted wood has settled and shed some leaves, you can remove the rest of the rootstock above the assemblage point. Cut about 3mm above the joining point.
