Land Grant institutions such as the University of Arkansas often offer low-cost strawberry petiole sampling programs that help growers know if they are over or under fertilizing their strawberries. Petioles are the stalks that attach leaves to stems.
Analysis is the best way to monitor the nutritional status and correct deficiencies that can occur in the strawberry crop, said extension specialist Amanda McWhirt. Proper crop nutrition ensures that yield and quality are optimized, and it protects against applying excess nutrients in the environment and incurring unnecessary expense. The key is to sample the correct tissue at the correct time. Early spring, when plants start to bloom, is the best time to test strawberry leaves and petioles.
Now is the time that growers should be pulling samples, McWhirt said. Once you have red fruit, youve missed the ideal window.
Growers should collect samples of mature leaves and petioles and send them to the Agricultural Diagnostic Laboratory in Fayetteville for analysis. Leaves are tested for nitrogen, potassium, sulfur and boron, and the petioles are tested for nitrate nitrogen. These nutrients are tested because they are important to producing a good quality strawberry fruit. The cost is $48 for six plant samples. Results are usually available within two to three business days after the sample is received. Extension specialists are also available to talk with growers about their results.
Strawberries need higher nitrogen levels in early spring when they are putting out new growth and flowering. Too much nitrogen can lead to too much plant overgrowth and soft fruit.
The analysis can also reveal excess or lack of nutrients that can make or break a berry crop. Too much boron, for example, can cause toxicity, but not enough boron can result in misshapen fruit.
It is important to determine if there are any nutrient deficiencies early in the season when growers still have a chance to correct the problem while plants are flowering, McWhirt said. Once fruit is close to being harvested, nutrient deficiencies cant be corrected.