Selecting plant material
Choose a healthy, young, semi-hard stem (not too soft, not old and woody) from a plant that is not diseased. It should have nodes (the small bumps where leaves and buds grow). For a graft, pick a rootstock that is strong and rooted, and a scion from a good plant. They must be closely related (for example, two citrus plants or two mango plants). Easy plants for a school: hibiscus, rose, money plant, coleus, Bougainvillea, sugarcane pieces; for grafting, rose or lemon.
Performing cuttings or grafts
Making a stem cutting
- Use a clean, sharp knife or cutter.
- Cut 12–15 cm with 2–3 nodes, slanted just below a node.
- Remove the lower leaves; keep 2–3 on top (and cut big leaves in half) to cut water loss.
- Plant 2/3 of the stem in moist soil or sand. Keep it in shade and water lightly.
The cut end forms a callus and new roots come from the node. Slanted cut = more surface to take up water.
Making a graft
- Cut the top of the rootstock and the base of the scion so they fit (a clean, slanted cut or a V-shape).
- Put them together so the cambium layers touch.
- Tie firmly with grafting tape or plastic strip, without crushing.
- Keep in humid shade until new leaves show.
The cambium is the thin green-white growing layer just under the bark. Cells there divide and join the two pieces. Dirty tools or loose tying let germs and air in and the graft fails.
Recording survival factors
Prepare at least 5 cuttings or grafts for each test. Change one thing at a time, such as leaves kept (0, 3, 6) or sun versus shade. Record in a table: date, number alive, number with new roots or leaves, notes. Survival % = alive ÷ total × 100.
Factors that matter: health of the parent piece, clean cut, number of leaves, moisture, shade and temperature, cambium match, and tying. Always keep one set as the control with the usual method.
Why use cuttings and grafts?
These are forms of vegetative propagation. They are fast, give plants like the parent (same flowers or fruit), and work for plants that do not make good seeds. A graft can also combine a strong root with a tasty fruit.
Key formulas and definitions
- Cutting: slanted cut just below a node; 2–3 leaves kept
- Graft: scion + rootstock with cambium touching
- Survival % = (alive ÷ total) × 100
- Change only one factor per test; keep a control
Worked examples
1. Out of 10 rose cuttings, 7 have new roots after 4 weeks. Find the survival percent.
7 ÷ 10 × 100 = 70%.
2. Why do we remove most leaves from a cutting?
The cutting has no roots yet, so it cannot take in much water. Leaves lose water as vapour; fewer leaves means less water loss.
3. A graft failed. The scion was tied loosely and the cambium layers did not touch. Why did it fail?
The cambium cells must touch to divide and join. A gap or loose tie stops the join, and the scion dries out.
4. Set A (3 leaves): 8 of 10 survive. Set B (8 leaves): 4 of 10 survive. What do you conclude?
Fewer leaves gave higher survival (80% vs 40%) because less water is lost. Keep a few leaves, not many.
5. Why do gardeners graft mango trees?
To get fruit like the best parent tree, and sometimes to use a strong root. Seeds may give a different fruit.
Common mistakes
- Cutting just above a node, not below it.
- Leaving too many large leaves on a cutting.
- Not matching the cambium layers in a graft.
- Changing many things at once, so you cannot tell what caused survival.