Know when and how to deal with runners for higher strawberry yields

Question: We have a strawberry patch at our home that has produced plenty of large fruit in the past. For the past two years, however, the fruits have been small and sparse. I mulch them with straw every year and try to encourage the runners to root. What can I do to get big fruits again? We have plenty of bees, so I don't think pollination is the problem.

Answer: You're dealing with one of biggest issues every strawberry grower faces: what to do when yields drop.

Whether you're growing June-bearing strawberries or ever-bearing varieties, there are a few things you can do to ensure a good yearly harvest.

First and foremost, make sure there's adequate nutrition in your soil and that the soil pH is appropriate. Strawberries grow best in a pH of 6.0 to 6.5. A soil test by the Penn State Extension will tell you your soil's pH and make recommendations to adjust it. Typically, here in Western Pennsylvania, our soil is more acidic than strawberries prefer, so it's likely that adjustments will have to be made.

Also, add a 1-inch-thick layer of compost to your strawberry bed every autumn to ensure the plants receive balanced nutrition.

Aside from soil preferences, you also need to treat the plants right. Unfortunately, you're doing the plants a disservice by allowing the runners to mature and take root every year.

Runner production causes the plant to put its energy into producing the runners, instead of producing large fruit. Rather than encouraging the runners every year, you should be cutting them off. It's only in the plant's third year of growth that runners should be encouraged. After three years, the mother plants should be dug out and discarded, and the runners should be allowed to take over.

To do this, you can remove all the strawberry runners by hand for the first few years, or you can simply run the lawnmower over the strawberry patch as soon as the plants are done producing fruit. It seems dramatic, but setting the mower blades to 2 inches high and cutting everything down will remove the runners and rejuvenate the mother plants. The plants will send up new, luscious growth soon after mowing, and ever-bearing types will produce their secondary crop as usual.

But, don't mow after the third year's fruiting crop is finished. Instead, allow the plants to set runners and encourage the runners to root. When autumn arrives, dig out and discard the mother plants and thin the rooted runners to five plants per square foot, thus reinvigorating your strawberry patch for another three years.

If you don't want to take the time to remove all the runners, an alternative is to do a complete overhaul by pulling out all the plants and replacing them with new, store-bought ones every three to four years.

Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control” and “Good Bug, Bad Bug.” Her website is jessicawalliser.com.

Send your gardening or landscaping questions to tribliving@tribweb.com or The Good Earth, 503 Martindale St., Third Floor, Pittsburgh, PA 15212.