Renovation in perennial strawberry fields

Benjamin Phillips<benp@msu.edu> and Cheyenne Sloan<sloanche@msu.edu>, Michigan State University Extension - July 11, 2023

Renovation is a key step after harvest to ensure maximum yields next summer.

Ripe strawberries on a bed of straw. — Ripe strawberries. Photo by Cheyenne Sloan, MSU Extension.

This article was synthesized and updated from several previous articles written by Eric Hanson, Mark Longstroth, Bob Tritten, Bernard Zandstra and Sushila Chaudhari.

Matted-row strawberry beds destined to be carried over for another harvest season need to be renovated annually. As strawberry fields age, yields and berry size decline while weeds and diseases problems increase. Deciding whether to renovate or remove a bed differs with every grower’s circumstance, such as market demand, land availability and production costs. Growers with high market demand, but limited available acreage, tend to retain beds longer.

If one does decide to renovate, start as soon as possible after harvest. This will give the plants plenty of time to grow. The earlier runner-plants develop, the higher they yield the following year, so delaying renovation will reduce yields next year.

There are four main steps when renovating matted-row strawberries: mowing, narrowing, weeding and maintenance.

1. Mow off the leaves

Mow off the leaves just above crown height if the plants are healthy. Mowing may not be desired if the plants are stressed by drought or root diseases because weak plants have difficulty developing new leaves. Also, do not mow the leaves if renovation is delayed for more than a few weeks after the end of harvest.

2. Narrow the rows

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, encouraging additional rooting. More than an inch of soil may smother the plants.

Some growers have success narrowing rows by treating the row middles with directed or shielded sprays of Gramoxone (paraquat). Gramoxone is a contact weed killer that is not mobile in plants, so it only kills treated tissues. This effectively narrows the plant row and does not expose new weed seeds by disturbing the soil. One problem with this approach is that it does not provide loosely tilled soil for the rooting of runner plants. It also does not throw soil back over crowns.

3. Weed control

Weed control at renovation will enable strong growth and rooting area for daughter plants to establish for fall bud formation and next year’s fruiting. At renovation, preharvest intervals aren’t generally a concern, and it can be a key point for weed control in a matted-row system. This is a great time to focus on perennial broadleaves and grasses with contact and residual herbicides to burn them down at renovation and help keep weeds down into the fall.

If there are many broadleaf weeds, especially perennial weeds (dandelion, field bindweed, wild carrot, horsenettle, vetches and common milkweed), in the field, it may be necessary to apply 2,4-D (Formula 40 or Embed Extra) immediately after the last harvest. In fields with dominating composite weeds (e.g., Canada thistle, dandelion, mayweed, ragweed, groundsel), clopyralid (Stinger) may be used instead of 2,4-D. Stinger has a Michigan 24c label. Do not include an adjuvant if Stinger is included in the spray mix. However, if the field has mainly annual broadleaved weeds, the herbicide application can wait until after tillage and mowing.

After tillage, apply residual herbicides to control weeds for the rest of the summer. For broad-spectrum, full-season weed control, include two residual herbicides in the post-renovation application. Effective mixes include a primarily grass herbicide (Dual Magnum, Prowl H2O) and a primarily broadleaf herbicide (Spartan, Ultra Blazer). See the table below for recommendations on common herbicides used in strawberries as well as when they can be applied in a matted-row system and weeds they’re effective against. As always, read the label before applying anything and if there are any questions, reach out to a local agricultural Extension educator.

Herbicide	Weeds of concern	Application timing
Herbicide	Weeds of concern	Renovation	Fall	Spring
2,4-D amine or choline	Smartweeds, velvetleaf, pigweeds, mustards, dandelion, bindweed, Canada thistle, plantains	X
Chateau** (flumioxazin)	Chickweed, common lambsquarters, mustards, pigweeds*, foxtail, dandelion, mallow	X	X	X
Devironl (napropamide)	Chickweed, common lambsquarters, pigweed, sowthistle, barnyardgrass, crabgrass, fall panicum, foxtail, witchgrass*		X	X
Dual Magnum (S-metolachlor)	Barnyardgrass, crabgrass, fall panicum, foxtail, witchgrass, pigweeds, nutsedge	X		X
Fusilade (fluazifop-P)	Barnyardgrass, crabgrass, fall panicum, foxtail, sandbur, witchgrass, quackgrass	X	X	X
Gramoxone** (paraquat)	Chickweed, common lambsquarters, mustards, pigweeds, ragweed, smartweeds, barnyardgrass, bromegrass, crabgrass, fall panicum, foxtail, witchgrass	X
Poast (sethoxydim)	Barnyardgrass, crabgrass, fall panicum, foxtail*, witchgrass	X	X	X
Prowl H2O (pendimethalin)	Common lambsquarters, pigweeds, barnyardgrass, crabgrass, fall panicum, foxtail, sandbur, witchgrass*	X	X	X
Select Max (clethodim)	Barnyardgrass, bromegrass, crabgrass, fall panicum, foxtail, sandbur, witchgrass*	X	X	X
Sinbar (terbacil)	Chickweed, common lambsquarters, horseweed, mustards, smartweeds, velvetleaf, barnyardgrass, bromegrass, crabgrass, fall panicum, foxtail, witchgrass*, horsenettle, plantains, quackgrass, sowthistle	X	X
Spartan (sulfentrazone)	Chickweed, common lambsquarters, pigweeds, smartweeds, field pansy, woodsorrel, white campion, sandbur, bindweed, nutsedge	X	X	X
Stinger (clopyralid)	Horseweed, pigweeds, clover, groundcherry, knotweed, plantains, Canada thistle, dandelion, sowthistle, vetch*	X	X	X
Ultra Blazer (acifluorfen)	Mustards, pigweeds*, smartweeds	X	X

* Weeds are rated as “excellent” control while all others are rated as “good.”
**Apply as a directed spray to row middles for preemergence control of annual broadleaves. Contact with strawberry plants will cause severe crop injury.

4. Maintenance – fertilizing and irrigation

The final step in renovation is to fertilize and irrigate the planting to encourage new growth and runnering. On heavier loamy soils, apply enough fertilizer to supply 50 pounds nitrogen per acre. On sandy soils, apply 30 to 40 pounds nitrogen at renovation and again in early August.

Do not neglect watering the field at renovation and during the remainder of summer. Plants need water to grow and all other efforts are wasted if the renovated plants do not get off to a strong start. Runner-plants that develop during July and August need adequate moisture to root and maintain a healthy leaf canopy to store food reserves for next year’s crop. With summers becoming drier, this will often necessitate irrigation on many sites.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).