PPDL Picture of the Week

June 11, 2015

Renovating the strawberry patch 

Bruce Bordelon, Professor, Department of Horticulture and Landscape Architecture, Purdue University

Most homeowner and small commercial strawberry patches are grown using the "matted row" system. In this system, plantings must be renovated after harvest to establish new crowns for next year's crop. New crowns that establish this summer will produce more fruit and better quality fruit next season than the old crowns. New crowns develop by rooting of daughter plants on the runners. Runner production begins under long days and warm temperatures. The crowns that produced the fruit this season are needed only as a source of new runner plants, so most of the old crowns can be removed to make way for new crowns. This may seem severe to some growers, but it is the best way to keep a strawberry patch healthy and productive.

For best results, renovation should be started immediately after harvest is completed to promote early runner formation. The earlier a runner gets set, the higher its yield potential and the larger its fruit. Growers should begin renovation as soon as the last good berries are harvested and before a large number of runners and new leaves develop.  The following steps describe renovation of matted row strawberry patches.

1.   Mow the old leaves off just above the crowns. Do not mow so low as to damage the crowns. (Picture 1, 2)

2.   Narrow the rows:  Reduce the width of rows to allow room for new runners to establish. Leave a strip of old crowns down the middle of the row to produce new runner plants. A desirable final row width to attain at the end of the season is 12-18 inches. Rows can be narrowed to as little as 6 inches during renovation. Use a tiller or cultivator to achieve the reduction. (Picture 3) Be sure to incorporate the old plant material and mulch thoroughly into the soil. (Picture 4)

3.   Rebuild the bed:  Pull a small amount of soil over the row after cultivation with a rake or hoe. Strawberry crowns continue development at the top, and new roots are initiated above old roots on the crown (Picture 5) so 1/2 - 1 inch of soil on the crowns will facilitate rooting. This also helps cover straw in the row and provides a good rooting medium for the new runner plants.

4.   Fertilize the planting.  Generally, nitrogen should be applied at about ¾ to 1½ lb. per 1,000 square feet depending on vigor. It is more efficient to split nitrogen applications into two or three applications at regular intervals, rather than apply it all at once. A good plan is to apply about half at renovation and half again in late August when flower bud development is occurring. A soil test will help determine phosphorus and potassium needs.

5.  Irrigate:  Water is needed for good plant growth. Don't let the plants go into stress. Ideally the planting should receive 1 to 1-1/2 inches of water per week from either rain or irrigation.

6.  Set runners: Sweep runners into the row by cultivation or hand set the runners until plant stand is sufficient.

7.  Provide adequate moisture and fertility during August and September to increase fruit bud formation and improve fruit yield for the coming year. Continue irrigation through this time period and fertilize if necessary. An additional ¾ to 1 lb. pounds of nitrogen per 1,00 square feet is suggested, depending on the vigor.

Click image to enlarge

Picture 1. Mowing the old leaves. Set the mower high to avoid damaging crowns.

Picture 2. Crowns after proper mowing. Only the leaf petioles remain and the crowns are not damaged.
Picture 3. Till to narrow the row to about 6 inches.
Picture 4. Several passes of the tiller may be necessary to thoroughly incorporate the old plant material and mulch.
Picture 5. Strawberry crown showing the new (light) roots growing above the older (dark) roots.