EFFECTS OF AIR CONTENT ON ROOT FORMATION OF EUPHORBIA AND BEGONIA CUTTINGS

Compressed peat briquettes are widely used for propagation, especially for Euphorbia. Jiffy is making briquettes of coir in addition to peat, and would like to know as much as possible about the physical characteristics of this new material used in compressed form. Top cuttings of Euphorbia pulcherrima cv. 'Lilo' and Begonia × hiemalis cvs. 'Blitz', 'Azotus', 'Bellona' and 'Netja Franje' were cultivated in two substrates (peat and coir) at different suction (0 and 5 cm or 0, 5 and 10 cm). When Jiffy-7 peat and coir briquettes were evaluated at different suctions for Euphorbia cuttings, those grown in coir under 5 cm suction showed better results. In those conditions, cuttings had a significantly higher total number of roots, number of roots outside the briquettes, and percentage of briquettes with visible roots than at 0 cm suction and peat at either suction. The cuttings' roots produced in coir 5 cm suction were very well developed, with a higher total number of roots, callus formation, length of roots, fresh and dry weight of roots and the volume of roots. The Begonia cvs. 'Blitz' and 'Azotus' showed similar results at 5 cm suction in coir briquettes with visible roots, number of roots outside the briquettes, total number of roots, number of second roots and length of roots. In 'Bellona' and 'Netja Franje', it was observed that Jiffy-7 to coir briquettes in 10 cm suction had the best results, with roots superior to 0 and 5 cm suction. The higher aeration in the coir briquettes allowed cuttings of species demanding greater aeration for rooting like begonias, which do not develop roots appropriately in peat-based substrates, to be grown in this substrate. Species that are sensitive to low air filled porosity like Begonia can develop well in coir briquettes.