A silicone grafting tube that is too loose will not hold the scion and rootstock in even contact, and the union heals unevenly or fails. A tube that is too tight can restrict the stem as it thickens through the healing period. For roses, match the tube to the actual stem diameter at the graft point, not to a single default size across the whole batch — PRO-ROSE is supplied across six diameters from 3.5mm to 8.5mm for this reason. Measure a sample of the batch before ordering rather than after a bad take rate shows up.
For vegetable grafting (tomato, pepper, eggplant), PRO-VEG is sized for the thinner, faster-healing stems typical of those crops, while PRO-CUC is built around the growth habit of cucumber, melon and watermelon. Fruit-tree grafting uses thicker stock and a slower healing window, which is what PRO-TREE is specified for.
If a batch mixes stem sizes, common with seedling stock that hasn’t been graded, it is worth sorting into diameter bands first and ordering tubes per band, rather than picking one size and accepting a lower take rate on the outliers. Our Grafting Sleeve and Clip Calculator will suggest a starting size and clip pairing, and our technical team can confirm against a sample if you send stem measurements with your enquiry.