Tips on renovating strawberries
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
Strawberry beds that are to be carried over for another harvest season need to be renovated. Deciding whether to renovate or remove a bed differs with each grower’s circumstances, such as market demand, land availability and production costs. As strawberry fields age, yields and berry size decline, while weeds and some diseases increase. Growers with high market demand but limited available acreage may need to retain beds longer. In the end, an educated decision requires thorough knowledge of your production costs and net returns over the preceding seasons. If you decide to renovate, start as soon as harvest is over. The earlier runner plants develop, the higher they yield the following year, so delaying renovation costs yield. Also keep in mind that renovated beds need abundant water in July and August. To renovate, follow these steps:
Mowing off the leaves just above crown height if the plants are healthy. If the plants are stressed by drought or root diseases, do not mow the leaves; weak plants have difficulty developing new ones. Also do not mow the leaves if renovation is delayed for more than a few weeks after the end of harvest.
Narrow the rows to 8 to 10 inches by cultivating with a rototiller or disk. Rototillers with tines removed above the row work very well because they toss some soil on top of remaining plants, which encourages additional rooting. However, more than an inch may smother the plants.
Some growers have had success narrowing rows by treating the row middles with directed or shielded sprays of the herbicide Gramoxone (paraquat). Gramoxone is a contact weed killer that is not mobile in plants, so it only affects treated tissues. This method effectively narrows the plant row, and does not expose new weed seeds by disturbing the soil. One potential problem with this approach is that it does not provide a loosely tilled soil which is best for rooting of runner plants. It also does not throw soil back over crowns.
Renovation is also a useful time to treat beds with amine forms of 2,4-D (Amine, Formula 40) for broadleaf weed control. Strawberry plants tolerate 2,4-D after harvest because they are not actively growing. If broadleaf weeds are a problem, apply 2,4-D a few days before mowing. This herbicide must be absorbed by the weed leaves to be effective so don’t mow off the weed leaves before applying 2,4-D. Sinbar can also be applied at renovation for preemergent weed control. Apply 3-6 oz of Sinbar 80W per acre, using the lowest rates on sandy ground or weaker plant stands. Mow plants first so that Sinbar is applied uniformly to the soil. Irrigate to rinse the herbicide into the soil. Michigan has a Section 18 label for the preemergent herbicide Spartan. Spartan is effective on common groundsel, field pansy, mayweed, white campion (white cockle) and pigweeds. Apply 4 to 8 oz Spartan 4F per acre, after plants have been mowed.
The last step in renovation is to fertilize. On heavier loamy soils, apply enough fertilizer to supply 50 lb N per acre. On sandy soils, apply 30 to 40 lb N at renovation and again in early August. Do not neglect irrigation on renovated beds.
Dr. Hanson’s work is funded in part by MSU‘s AgBioResearch.