Spring Grafting: From Preparation to Application

Preparing ahead is vital.

As we approach the spring grafting season, we would like to outline some key points that you and your technical teams should take into account.

Step 1: Gather the Information That Will Guide You

The first step is to carry out a careful count of the trees that need to be grafted. This should be done separately for each variety.

A shortage of pollinizers harms a young orchard far more than a few missing trees of the main variety, so particular care should be taken to count the pollinizers precisely.

In a large orchard, the trees may be spread across different blocks located far apart from one another. Just as you would plan your shopping in a very large supermarket, you should also organize these counts by location/block — otherwise you will have to run back and forth from one aisle to another.

Finally, if there are significant differences in the size (thickness) of the trees to be grafted, this should also be treated as a variable — because a good diameter match between the bud and the rootstock is an important factor affecting your success rate.

These plants should be marked in different colors so they can be easily identified from a distance. Using different colors on the tree guards and plotting them on a basic chart will help with this.

Step 2: Collecting Graft Material

The graft material (buds) will determine the variety of the plants that grow in your orchard. It must be collected with a very high level of precision. There must be no margin of error when it comes to varietal trueness.

Avoid accepting graft material from others unless you are sure of its source and were personally involved in collecting it.

Collection Timing and Quantity

• Graft material (scionwood) should be collected during the dormant period (until the end of February) and stored under ideal conditions that guarantee its freshness.
• Ideally, scionwood 100-110 cm in length should be taken. Because the scion will lose viability at both ends, starting with relatively longer scions lets us ensure at least 4-5 usable buds from each one.
• To ensure you end up with enough usable buds, we recommend having at least 30% more buds than the amount needed.

Matching Scion Width

The width of the scionwood should be as close as possible to the width of the plants to be grafted. If there are significant differences in plant widths, refer to your detailed plant count as described above when collecting the scionwood, and collect scions that match the width of your rootstocks.

All scions should be sorted into groups of the same size and variety — any mixing will affect both your grafting success and varietal reliability. It can also be useful to mark one of the scions with the same colour used for the rootstocks in the orchard. Make sure the paint does not cover the buds.

Storing Scions

Scions should be slightly damp and placed in airtight bags. We recommend putting a piece of damp newspaper (with excess water squeezed out) into each bag before sealing it. The damp paper and the sealed bag will help retain moisture. The bags should then be placed in a refrigerator kept at +4 to +6 degrees C. Take care not to damage the buds when storing the scion bundles.

Step 3: Timing

Historical climate data shows that the ideal spring grafting time for Santarem in Portugal is around the end of the first week of April. In Turkey, this timing varies by region — it may be around late March to mid-April for the Mediterranean/Aegean coast, mid to late April for Central Anatolia, and late April to early May for Eastern Anatolia.

This is when we begin to see activity in the plant, which we can tell by observing night temperatures above 12 degrees. Keep in mind that seasons vary from year to year, so weather conditions should be monitored closely during this period in order to make small adjustments to the grafting time.

Step 4: Cutting Back the Rootstock

One of the most important factors affecting your grafting success is cutting off the top of the rootstock plant a few weeks before the planned grafting date, so that the plant to be grafted uses up its SAP (sap fluid).

Of the two types of SAP, xylem sap is the fluid made up of a solution of hormones, mineral elements and other nutrients that moves from the roots to the buds and leaves.

How to Do It

To trigger this sap flow, the plants to be grafted (rootstocks) should be cut with a slightly slanted cut in the second week of March at a height of about 70 cm (roughly 10-15 cm above the plant guard).

Don't delay this step. Depending on the differences in sap and root pressure caused by the gap between day and night temperatures, the flow of SAP from the cut point can take weeks. In warmer years the process will be faster.

Monitoring the Process

The cut plants will gradually begin to release SAP from the cut. This can take several weeks. Grafting must not be carried out until this flow has stopped or dropped to a barely noticeable level.

The cut anticipates and speeds up this SAP flow from the roots to the stems, and within a few days the buds will begin to swell and turn reddish.

After this final preparation step, the plants should be observed carefully and their behaviour noted several times a week. Remember: plants in different plots (or even in different sections of the same plot with different sun exposure) may show different progress, timing and speed.