From 2022-2024, we evaluated the performance 15 strawberry cultivars grown in plasticulture system using black and white-on-black plastic mulches (Figure 1) at two locations: Southwest Purdue Agricultural Center in Vincennes, IN (USDA hardiness zone 6b), and Meigs Purdue Agricultural Center in Lafayette, IN (USDA hardiness zone 6a).
Figure 1. ‘Camarosa’ strawberry grown in black (left) and white-on-black (right) plastic mulches at Lafayette, IN on October 13, 2022 (Photo credit: Jeanine Arana).
Strawberries were harvested for two seasons. Plug plants were used in the study and were transplanted on September 7, 2022, at the Vincennes location and on September 8, 2022, at the Lafayette location. The trial ended after the second years’ harvest in June 2024.
During the experimental period, the monthly average temperatures at the Vincennes location were 1.4 to 5.0 °F higher than that at the Lafayette location. The soil type at the Vincennes location is an Alvin fine sandy loam, while the soil at the Lafayette location is a mix of the Toronto silt loam and Millbrook silt loam complex and Drummer silty clay loam.
In this article, we summarize the effects of plastic mulch color on strawberry performance over two harvest seasons and offer insights to help guide the choice between black and white plastic mulch for plasticulture strawberry production in Indiana.
Study Findings
The effects of mulch color varied by year and location, though trends were generally consistent across cultivars. In 2023, the yields at both locations were negatively impacted by frost damage, with particularly severe losses at the Lafayette site.
Fruit production — At the Vincennes location in 2023, plants grown on black plastic mulch produced significantly higher yields (average across 15 cultivars: 0.69 lbs/plant) than those on white plastic mulch (0.56 lbs/plant). No significant difference was observed at the Lafayette location, likely due to the extent of frost damage. In 2024, yields were higher on black plastic mulch (0.92 lbs/plant) than on white plastic mulch (0.63 lbs/plant) at the Lafayette location. However, the trend reversed in the second year harvest at Vincennes, where plants grown on white plastic mulch yielded more (1.07 lbs/plant) than those on black plastic mulch (0.91 lbs/plant).
At the Lafayette location, fruit harvested from plants grown on black plastic mulch were consistently larger in both years compared to those from white plastic mulch. No significant differences in fruit size were observed at the Vincennes location.
Earlier harvests (by approximately 7–10 days) were observed on black plastic mulch during the first year in Vincennes and the second year in Lafayette. This effect was not seen during the second year at the Vincennes site.
When combining yield data from both years, black plastic mulch produced significantly higher yields than white plastic mulch at the Lafayette location (1.16 vs. 0.84 lbs/plant). In Vincennes, opposing trends across the two years resulted in similar total yields between mulch types: 1.63 lbs/plant on white plastic and 1.60 lbs/plant on black plastic.
Plant survival — Prior to the second year’s harvest, plant survival at the Vincennes site was lower on black plastic (76%) compared to that on white plastic mulch (84%). The lower plant survival was likely due to greater heat and drought stress the plants faced on black plastic during the summer following the first harvest. In Lafayette, overall survival was higher (93%), with no significant difference between mulch types.
Runner development — Across both locations and cultivars, plants grown on white plastic mulch consistently produced more runner biomass during the summer following the first harvest compared to those grown on black plastic mulch.
Factors to Consider When Choosing Between Black and White Plastic Mulches for Strawberry Production
If maximizing yield is the top priority, black plastic mulch may be the preferred option. Plasticulture strawberry yield is largely determined by the number of branch crowns, which develop primarily in the fall. Black plastic mulch led to higher soil temperature compared to white plastic mulch, creating more favorable conditions for branch crown formation, and potentially resulting in higher yields the following spring.
However, there is likely a threshold for the number of branch crowns that can support optimal yields, which may be influenced by factors such as cultivars and fertilizer input. Once this limit is reached, additional crown development may not translate into increased yield. This may help explain the results observed in the second year’s harvest at the Vincennes location.
Runner production is undesirable in plasticulture systems. To prevent daughter plants from establishing, runners need to be removed promptly during the summer following the first year’s harvest. Plants grown on white plastic mulch tend to produce more runner biomass, which may increase the labor required for runner removal.
One advantage of using white plastic mulch over black is its ability to keep the soil surface cooler. This can be particularly beneficial in situations where ripe fruit remains on the mulch for an extended period before harvest, such as in u-pick operations. Additionally, the cooler soil temperatures may enhance plant survival during the summer following the first year’s harvest—especially in soils with lower water-holding capacity, which tend to heat up more and impose greater water stress on crops during hot, dry conditions.
Frost damage is one of the major challenges in plasticulture strawberry production in Indiana. For fields without overhead irrigation, floating row covers must be readily available and deployed promptly when frost or freeze events occur during the critical flowering period. Using white plastic mulch may help delay flowering compared to black plastic mulch, potentially reducing frost risk to some extent.
However, this strategy does not guarantee reduced risk, as late frost events can still occur as late as May in southern Indiana. In some cases, we observed that frost caused more damage to later-blooming plants than to earlier-blooming ones, as the early bloomers had already set fruit by the time the frost occurred. To better mitigate frost damage, we recommend consistently implementing frost protection measures whenever there is a risk and strategically spreading peak bloom timing—either by planting cultivars with different bloom periods, using a combination of black and white plastic mulches, or using straws for winter protection.
A detailed discussion of the cultivar evaluation results will be provided in a forthcoming article.