Black Polyethylene Mulch Does Not Reduce Yield of Cucumbers Double-cropped with Tomatoes under Heat Stress

Black polyethylene mulch is preferred for producing early spring tomatoes (Lycopersicon esculentum Mill.) because of its warming effect on the soil around the roots. However, using the same mulch for double-cropping cucumbers ( Cucumis sativus L.) with tomatoes is considered by some growers to be undesirable because of the belief that heat accumulation under the mulch in midsummer or early fall is detrimental to cucumber yield. Eight studies were conducted from July to September in 1994, 1995, and 1996 to determine the effects of mulching spring tomatoes with black vs. white polyethylene mulch on the growth and yield of subsequent cucumber crops. Soil temperature recorded after planting cucumbers ≈4:00 pm for 3 weeks was higher under black mulch than under white mulch. Color of the mulch did not affect leaf length, leaf width, and plant dry weight of cucumbers in six of the eight studies. Cucumbers grown on black mulch produced longer leaves in one study and wider leaves in two studies, and plant dry weight was lower in two studies. Mulch color had no significant effect on the premium or total yields of cucumbers in all but one study. Cucumbers grown on black mulch produced lower percentages of culls in two studies.