Growing Strawberries Organically

Organic strawberries succeed or fail mostly on decisions made before and at planting: certified disease-free plants, a sunny, well-drained site with no recent tomato-family crops, crowns set at the right depth, and the patience to pinch off first-year flowers. After that, the main jobs are annual renovation of June-bearing beds, winter mulch in cold climates, and keeping the canopy open enough to limit gray mold. Expect a bed to last a few years, not forever.

Pick a type: June-bearing, everbearing, or day-neutral

The type you choose sets your harvest timing, your pruning routine, and how exposed your crop is to late-summer pests.

The descriptions above come from Oregon State University Extension's home garden strawberry guide, which notes that day-neutral plants keep producing except when temperatures drop below 40°F or rise above 90°F. University of Maryland Extension describes June-bearers as the most commonly grown type.

Start with certified plants

Oregon State's advice is direct: buy only certified, disease-free plants from a reputable nursery, and don't propagate from old patches. Strawberry viruses can't be treated once they're in the plant. Transplanting runners from a neighbor's aging bed is the easiest way to bring one home.

Virus outbreaks in strawberries are uncommon but can be severe when they happen. A Clemson University pathologist writing for the Southern Region Small Fruit Consortium describes how the last major outbreak in the Southeast, in 2012–2013, traced back to a single nursery source in Nova Scotia. That's the case for clean stock in one example: the problem came in on the plants. More on how certification works is in why berry plants should come from certified clean stock.

Site and soil

• Sun: Full sun, away from trees and buildings that cast shade.
• Drainage: Oregon State says the water table should be at least 14 inches below the soil surface.
• pH: 5.6 to 6.5, per Oregon State. Test first and adjust ahead of time. See soil test results explained.
• Crop history: Avoid ground that recently grew potatoes, tomatoes, peppers, eggplant, raspberries, or blackberries. All of them host verticillium wilt, a soilborne fungus that also attacks strawberries.

Planting depth and spacing

Crown depth is the most common planting mistake. Oregon State says to set plants so the midpoint of the crown is level with the soil surface. Too deep and the crown rots. Too shallow and the roots dry out.

Two layouts are common in home gardens:

• Hill system: Plants about 12 inches apart in all directions, with all runners removed. UMD recommends this spacing. Oregon State gives 12 to 15 inches.
• Matted row: Mother plants 18 to 24 inches apart in rows at least 36 inches apart, per UMD, with daughter plants allowed to root and fill the row.

Planting time varies by region. UMD suggests March or early April in Maryland. Check the berry planting calendar for your area.

The first-year flower rule

For June-bearers, UMD advises removing the flowers for the entire first season so the plant builds a large root system. You give up a small first-year crop in exchange for a much stronger bed. For everbearing and day-neutral types, Oregon State recommends removing only the first flower cluster before letting plants fruit.

Renovating June-bearing beds

A matted row of June-bearers gets crowded, weedy, and less productive each year unless you renovate it after harvest. University of Minnesota Extension explains the timing: next year's fruit buds form in the fall, generally in September and October, so renovation should happen shortly after the summer harvest. UMN also says not to renovate in the planting year or to renovate day-neutral varieties.

1. Weed right after harvest. In an organic bed this means hand-pulling and hoeing.
2. Mow or cut the old leaves about 2 inches above the crowns. UMD gives 2 to 3 inches. The goal is to avoid damaging the crowns.
3. Fertilize based on your soil test. Compost or an organic nitrogen source works here.
4. Narrow the rows. UMN suggests cutting rows back to as little as 6 inches wide so they fill in to 12 to 14 inches. UMD suggests thinning daughter plants to about 6 inches apart.
5. Water. UMN recommends about one inch per week, from rain plus irrigation, while leaves regrow.

Winter mulch in cold climates

Strawberry crowns are more tender than they look. UMN's home strawberry guide says crowns may be killed at 15°F. It recommends 4 to 6 inches of weed-free straw, applied after two or three frosts have hardened the plants off and temperatures are staying below 40°F. In spring, rake most of it off when growth begins and leave some at the base of the plants as summer mulch. If frost threatens after bloom starts, cover the plants again with straw or a row cover.

Straw is the traditional choice. UMD notes that other biodegradable mulches work too. For a comparison of materials, see the best mulch for a vegetable garden.

Diseases and pests without sprays

Gray mold (Botrytis) is the main fruit rot in home plantings. Oregon State notes that it overwinters on dead plant material. Removing old leaves at renovation and not letting the canopy get dense are the main non-chemical controls.

Root rots are mostly a drainage problem. Prevent them by choosing the site well. If you can't, use raised beds.

Spotted wing drosophila matters most for day-neutral and everbearing plants that fruit into late summer. See spotted wing drosophila in home berry plantings.

How long a bed lasts

Oregon State says plantings stay productive for three to five years. Yields usually peak in the second year and decline after that. When a bed fades, start a new one in a different spot with fresh certified plants rather than transplanting runners from the old bed, which can carry disease forward.

Strawberries are one part of a larger berry plan. For site selection, clean stock, and how strawberries compare to cane fruit, go back to growing berries organically.