Gordon Johnson, Extension Ag Agent, Kent Co.; gcjohn@udel.edu
More growers in Delaware are growing strawberries using the annual production system on plastic. This system offers the advantage of an earlier and longer harvest season in the spring and potentially higher yields than the matted row system. However, costs are higher and management is more intensive.
While the annual plasticulture system offers several advantages, it is rather unforgiving if one or more critical operations are not performed in a timely manner. The following are some keys to success with the annual strawberry production system:
1. Plan ahead. Locate the source of tips or plug plants well ahead of time, no later than June of the year that you intend to plant.
2. Obtain quality plants from the nursery. Generally growers will either buy plug plants that have already been rooted in cell trays or they will buy tips that they root themselves in plug trays. Plug plants have the highest establishment success rate. Bare root plants may also be available but are much more difficult to manage at planting and as such establishment success rate is lower. Make sure plants are disease free. We have recommended plug plants grown from northern sourced tips (out of Canada primarily).
3. Make sure that the area to be planted is well drained and the ground is available to make beds in August. Soil fumigation is required for best yields and you will need sufficient lead time to allow for the fumigant to dissipate (20 days). Raise high beds, the higher the better, to allow for good drainage. Lay plastic on the high beds making sure there is a firm crowned bed. Work in necessary fertilizer according to recommendations (soil test for P and K recommendations, 60-75 lbs of N per acre) to bed areas prior to bed formation. Devrinol herbicide can be applied to the surface of the bed and between beds. Apply additional herbicides to row middles after laying plastic (Devrinol, Sinbar, Chateau, Dacthal are labeled).
4. Planting date is extremely critical. Target the first week in September with a range from the last week in August to the second week in September. Plantings after the second week in September have lower yield potentials.
5. Plant at the proper depth using a water wheel type transplanter or a dibber by hand for smaller acreage. Plant so that the plug is at the level of the soil or is just covered with a small amount (1/8”) of soil but avoid getting soil into the crown of the plant. Deep planting will result in reduced stands and weak plants due to rotting in the crown area. Shallow planting (where part of the plug is out of the ground) will result in plugs desiccating and reduced stands.
6. Make sure you have ordered floating row covers so that they are available to cover plantings later in the fall.