– Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
On June 9, at our Georgetown research station, we received 4.2 inches of rainfall in a one-hour period. Many of our vegetable research plots were temporarily flooded and most of our plasticulture research area had water that topped the beds.
If this flooding would have lasted for more than 24 hours, most of our crops would have been lost. However, there was enough drainage early on so that the majority the area has come through, albeit with some complications. The following are some pictures that show the recovery and losses:
Pepper plants with leaf drop. Ethylene buildup in saturated soil conditions can cause leaf drop, flower drop, fruit drop, or early plant decline in many vegetable crops. The bed area around this plant was saturated for two weeks. For the plant to recover, the bed must dry out to allow the plant to regenerate roots. The pepper plant has additional sets of buds to allow for new leaves to form but the recovery, if it happens, will put the plant several weeks behind other non-affected plants. Another concern is potential for root rots. In severe cases, cutting away the plastic can save a crop by allowing for better drying out and aeration.
Watermelon plant in saturated bed conditions after flooding showing little growth. Oxygen starvation to vegetable roots will cause roots to cease to function resulting in plant stunting, or collapse, with limited recovery potential. For this plant to recover the bed must dry out and aerate enough for the plant to fully regenerate roots.
Flooded pickling cucumber planting. Soils in in this area stayed saturated for 3 days while seeds were germinating. Lack of oxygen caused seeds to deteriorate and plants did no emerger in much of the area.
Tomatoes fully recovered from temporary flooding. In this case the crop did not drop leaves and was able to regenerate new roots quickly.
Our watermelon variety trial stopped growing and aborted fruits after the flooding but has now fully recovered and plants are starting to fill in. The beds were allowed to dry out for 9 days after flooding and then the crop was fertigated with nitrogen and sulfur. New fruits are now being set but the trial will have few early watermelons.