The effects of incorporating a hydrogel polymer into sand on the development of selected horticultural plants grown under saline conditions has been demonstrated. In separate experiments, the seeds of tomato (Lycopersicon esculentum Mill.), lettuce (Lactuca sativa L.) and cucumber (Cucumis sativus L.) were germinated in sand/swollen hydrogel polymer mixture (25: 75, v: v) with added Hoagland nutrient solution. At cotyledon + first true leaf stage, the plantlets were transplanted into polythene growbags containing a range of sand/swollen hydrogel polymer combinations (0: 100, 25: 75, 50: 50, 75: 25 and 100: 0, v: v). Saline solutions containing NaCl, CaCl2 and MgCl2 were prepared as molar solutions and applied at combined concentrations as follows; Control (Hoagland), 2000, 4000, 8000, and 32 000 ppm. Application of the appropriate solution to the growbags was made twice per week, alternating with a comparable watering regime. Harvesting was carried out after 14 and 28 d. Polymer incorporation encouraged growth of all species under all saline conditions, the order of effectiveness of the polymer contents being as follows; 75%>50% 25% 100%>0%. At high salinity (32 000 ppm) plants of the test species were reduced in growth but appeared to be tolerant at all levels of polymer incorporation; in pure sand the level of tolerance in tomato and cucumber was <8000 ppm and in lettuce < 4000 ppm. Generally, dry weight, leaf area, succulence, chloroplast pigments (chlorophyll a, chlorophyll b, and carotenoids), photosynthetic activity, total amino acids, proline, and protein contents were increased with polymer incorporation compared with pure sand. This hydrogel polymer appears to be highly effective for use as a soil conditioner in horticulture, to improve crop tolerance and growth in a sand or light gravel substrate under saline conditions. It is intended to confirm the results of these studies by field trials.