Keeping Your Strawberry Bed Productive - U of I Extension

News Release

Keeping Your Strawberry Bed Productive

This article was originally published on May 20, 2008 and expired on June 30, 2008. It is provided here for archival purposes and may contain dated information.

Strawberries can maintain their productivity for many years after planting. However over-crowding, weed competition, disease and poor growth can reduce the lifespan and yield over time. A few key management tasks after harvest will help keep strawberry beds productive for many years to come.

With the range of varieties out there, strawberries vary greatly in maturity times, flavor, fruit size, and disease resistance. Many recent varieties have good resistance to the diseases of the past which limited the life-span of the average planting to just a few years. Many of today's varieties, if properly managed, may stay productive for as long as 5 to 10 years or more. Thus, choosing varieties, especially those with good root disease resistance, along with good site preparation are important to maintain longevity and productivity.

As the harvest season for strawberries winds down in June, the important task of "renovation" gets underway. Strawberry bed renovation combines several different management tasks that keeps the planting healthy and vigorous and helps "set the stage" for good fruit production next year.

Renovation should be done soon after the last berries are picked; no later than 2 to 3 weeks after harvest. This is a period in which the plants will have a brief after-harvest dormancy period. Renovation involves mowing off old foliage, managing rows and thinning excess plants, fertilization and weed control, along with irrigation if rainfall is limited.

Start the process by mowing the old foliage, raking and removing it. This will help reduce foliar diseases leaves and stimulate new foliage growth. Be sure to sharpen your mower blades, and cut about one inch above the crown or growing point. Do not cut into the crown or the plants will be damaged.

Next, reclaim the original rows and pathways over-grown with last season's runners. Use a small tiller to cultivate between the rows and narrow them to 1 to 2 feet in width. This will involve some loss of plants. If the planting is several years old, judicious removal (by hoeing) of 10-25% of older plants in the row middle will thin the main row and provide room for younger plants to grow and develop. Younger plants are generally more productive than older plants which decline over time. In general, 4 to 6 inches should be left between plants in the row.

The next step is to fertilize the beds. Broadcast 1 to1.5 lbs of a general analysis fertilizer such as 13-13-13 for every 100 square feet of bed area. An equivalent substitution of a soluble fertilizer such as Miracle GroTM can also be used. Granular fertilizers should be watered in. Fertilizer will also help stimulate new growth.

An interesting characteristic about strawberries is that when dormant, they are somewhat resistant to the effects of 2,4-D, a common broadleaf weed killer. Thus they can be over-sprayed with this herbicide in early winter through early spring dormancy, and also during the brief summer dormancy period. This is a good method to tackle difficult broadleaf weeds such as dandelions that have a foothold in the bed. Be sure to use an amine form of this herbicide, and one without other materials mixed with it. Sethoxydim (Vantage, Poast) is a selective grass killer that can also be sprayed over strawberry plants. It should be applied before runners and new "daughter" plants develop. Dacthal or DCPA is a pre-emergence herbicide sold for home-owner use which will prevent some weeds from germinating, and can be applied early in the spring and during the renovation process. Be sure to follow label directions carefully on all products used for weed control, as varying degrees of injury can occur from herbicide use. Different materials should not be mixed together. The use of RoundupTM should be avoided in strawberries except as a very carefully shielded spot treatment. Note that PreenTM is not labeled for use in strawberries.

As the plants come out of summer dormancy, they will put on new leaves. If foliar disease or spotting has been a problem, then a few well-timed fungicide sprays will help protect the new foliage, especially if it is a wet summer. Runners will soon develop and new daughter plants will form at the tips of the runners, rooting easily in place. These can be allowed to randomly set and take root on the row edges or can be manually directed to fill bare spots in the row. The newly set daughter plants on the tilled row edge can be very productive in the next year.

Strawberries will begin setting buds for next year's crop in the early fall. So care and management to keep them vigorous and forming new plants after renovation is important, particularly providing supplemental water during dry periods. A follow-up application of soluble fertilizer in the late summer (early-mid August) can help maintain vigor as buds are set. Avoid over-application of fertilizer or plants may not harden-off well for winter. As noted, avoid 2,4-D use for late fall weed control until after several hard freezes have occurred and plants are dormant. Cover them with 2 to 4 inches of clean straw to reduce frost heaving and root damage through the winter. Usually late November to early December is a good time to do this.

For more information on growing strawberries and other small fruit, the publication "Small Fruit in the Home Garden", Extension circular number C-1343, is available through your local county Extension office.

Source: Anthony Bratsch, Extension Educator, Horticulture (Serving East-Central and Southeastern Illinois), bratsch@illinois.edu

Pull date: June 30, 2008