It’s a battle of the fittest. Cucumber and weed plants emerge from the soil at about the same time. Who will win out in this growth cycle? Will the cucumber plants grow faster, or will the weed plants sprout up to the sky like the beanstalk in the Jack and the Beanstalk fairy tale? More often than not, a grower will say the weed plants out-shade the cucumber plants every time.
When the weed plant overshadows the cucumber plant, it can reduce yields, downgrade quality, harvest fewer cucumbers and lessen quantity at the farmers market, grocery store or wholesaler.
What’s the answer to this weed problem? What growers can do is see that their cucumber plant grows vigorously, so it can overshadow or spread out over the weed plant. According to the University of California’s Integrated Pest Management (IPM) program, some cucurbits such as cucumbers grow slowly, so growers may need to seek a more serious weed control plan. The IPM program recommends trying an integrated approach to weed management using herbicides and good cultural practices such as cultivation, hand hoeing, fumigant and herbicide use, and crop rotation.
The IPM program recommends that growers monitor their fields for weed species and keep good records of what species are in specific fields, how often they appear and pinpoint which hard-to-control weeds are present. The center advises to do this before growers cultivate so they can identify any weeds that may have escaped a preplant treatment. Later before harvesting, the center advises to conduct another survey of weeds present and any that may be producing seeds. Record what those are for future reference. Additionally, the IPM program advises growers to avoid planting cucumbers in fields with high populations of weeds such as common purslane, field bindweed or nutsedge because they are difficult to control using typical weed management strategies. Here’s more about these weeds:
1. Common purslane
According to the Virginia Tech Identification Guide and Weed Scientist Michael Flessner, common purslane is a summer annual that can tolerate drought as well as poor and compacted soils. It has a taproot with fibrous secondary roots. Seedlings are hairless. Young, maroon-tinted leaves appear opposite of each other. Thick leaves grow 1/4 to 1-1/4 inch long. These leaves are round at the apex, narrow at the base, and smooth at the margins. Stems of the common purslane are smooth and purplish-red to green in color. They may grow from 4 to 20 inches in length. Flowers are yellow with five petals and are found in the leaf axils or clustered at branch ends. Its fruit is an oval shape and may split open at its middle.
2. Field bindweed
The field bindweed is a perennial weed that climbs easily like morningglory and even has flowers like white morningglory, according to the Virginia Tech Weed Identification Guide. Seedlings appear dark green in color and have white to light-green veins. Its cotyledons look square and equally wide with an indented tip. Leaves are triangular and may have hairs or may not. The base of the leaf is pointed, and its lobes grow outward. Stems of field bindweed rest near the ground or may grow onto other plants. Stems may or may not have hairs. This plant has a twisting taproot that grows deeply into the ground. Flowers look white to pink in color and may grow from 3/4 to 1 inch long. Their shape may take on a funnel appearance and have small bracts separate from the flowers, helping growers to identify them from other weeds.
There are two types of nutsedge—purple and yellow:
- Purple nutsedge is a perennial that grows about 2-1/2 feet high, according to the Virginia Tech Weed Identification Guide. It has three-sided, triangular stems. Leaves are yellow to green in color and appear shiny. They are 5 to 8 millimeters wide with a ridge along their midvein. Purple nutsedge leaves grow in groups of three at the plant base and have no hairs and no auricles. Leaves stretch to a sharp point. Stems stand erect and unbranched, and they produce terminal spikelets, which individually can appear reddish-purple to reddish-brown in color. This nutsedge produces chains of tubers, which develop along the rhizome of the plant.
- Yellow nutsedge looks and grows similar to purple nutsedge, according to the Virginia Tech Weed Identification Guide, but the two do have differences. Purple nutsedge leaves taper to a point abruptly, and yellow nutsedge leaves taper to a point gradually. Their seedheads are different, too. Naturally, purple nutsedge seedheads are purple, and yellow nutsedge seedheads are yellow. In addition, tubers of purple nutsedge are connected in chains and are bitter, whereas yellow nutsedge tubers are solitary and sweet.
With identification of these key weeds and a good weed management plan in hand built upon good recordkeeping, growers can control weeds and potentially prevent their growth before they overshadow cucumber plants. In the end, the fittest plant wins during the growing season. Let’s hope that is the cucumber plant.