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How to spot seedless cucumbers under stress
from The Grower June 2023
by The Grower
Seedless cucumber is a fast-growing crop compared to tomatoes and peppers. One can start harvesting as early as 50 days from seeding while tomatoes take 100 to 100 days and peppers up to 130 days. Cucumbers, therefore, react quickly to changes in temperature, humidity, nutrition and stresses. At press time, mid-May, we are currently dealing with hot temperatures and smoke in the western provinces and cucumbers are reacting by aborting cucumbers (Figure 1). There are multiple signals these cucumbers plants are sending.
• Very dark and droopy leaves.
• Thick stems and also thick leaves
• Very dark green leaves
• Fruit abortion, as if the plant suddenly decided not to feed the cucumbers
Understanding these signals and corrective actions:
1. Plants are very vegetative. Thick stems, dark green and thick leaves, leaves not in “prayer” mode. The “prayer leaves” term is used where leaves are spread and the strong petiole is upward looking. They appear to be oriented in such a way that they are trapping maximum sunlight.
2. These plants became more vegetative due to cooler night temperatures in February. So adjust night temperature to 20-21°C and day temperature to 22-23°C.
3. From a plant viewpoint, any food made through photosynthesis is being sent to roots, shoots and flowers but not enough food is being sent to the fruits.
4. The picture above indicates how plants reacted to the grower’s management practices.
5. The fertilizer program in the above case was more heavy in ammonium nitrogen compared to nitrate nitrogen. Avoid ammonium-based fertilizers especially where water is used as a growing medium and also in hydroponics systems.
6. Figure 2 shows how the plant was sending a large portion of food resources to massive roots. In figure 3 you can see the leaf coming out of a node where fruit has developed. Remove this leaf and also check your night temperature. It is probably cooler than the recommended range. Another vegetative signal.
Growers must be aware of many strategies to make plants vegetative or generative. If you
