Guide to Fertilizing Strawberries for Maximum Yield

Fertilizing strawberries is different from many other edible crops. That's because managing nutrients correctly depends on whether they are June bearing or day-neutral. Feeding plants for even, balanced growth is key to harvesting a good crop, and to keep your patch producing for more than one year.

Here’s what you need to know about fertilizing strawberries for healthy growth and maximum crop size.

When to Fertilize Strawberries

For both day-neutral and June-bearing strawberries, fertilizing begins before planting. These berries use lots of nitrogen to produce runners and set fruit, so it's important to start out with slightly acidic, rich, well-draining soil. Work in compost, well-rotted manure, or peat and add a balanced, slow-release NPK fertilizer into the top 6 inches two weeks before planting.

To fertilize potted strawberry plants, use a combination of quality potting mix, compost, and granular fertilizer.

The goal of fertilizing is to maintain pH level while supplying enough nitrogen for roots and foliage but not at the expense of flowers and fruit. A slow release NPK 10-10-10 or 20-20-20 is the best choice starting out. Plenty of organic alternatives are available including blood meal, which contains a good percentage of nitrogen.

When to Fertilize June Bearing Strawberries

Fertilize June-bearing strawberries in mid to late summer. Strawberry seedlings are planted in spring but berries grow from buds formed the previous autumn.

In the first planting year, June-bearing types need the entire summer season to establish roots strong enough to support a crop. All flowers are removed and plants are fertilized once in August.

In subsequent years, beds are renovated following harvest. (Renovating a strawberry bed means thinning existing plants and allowing the runners to become new plants. If you don't renovate at least every other year, the roots choke each other out.) Feed plants in mid to late July, after renovating, to encourage healthy bud production in autumn.

When to Fertilize Day-Neutral Strawberries

The first year growing day-neutral strawberries, fertilize when fruits appear after the second flush of flowers. First flowers are removed so add the first feeding in mid-summer. Use a balanced 10-10-10, or, if plants appear weak, an organic application of bloodmeal should boost growth. If flowering is spotty, bonemeal supports root growth and encourages flowering. Organic products can be applied every six weeks but should be discontinued at the end of the growing season.

In subsequent years, fertilize day-neutral strawberries in early spring as soon as new leaves appear. Use a balanced NPK 10-10-10 or 20-20-20. Apply a second feeding when fruit starts to develop. Foliar sprays and compost tea can be added as often as every two weeks to boost fruit production.

When to Fertilize Strawberries Grown in Pots

Fertilize strawberries grown in pots when leaves first appear in spring and again when berries start to form. Feed the plants every two weeks with compost tea or a foliar spray for continued flower and fruit production during active growth. If you plan to overwinter your pot for a second season, don’t fertilize during winter months.

How to Fertilize Strawberries

Strawberries are short-lived perennial plants that grow from shallow rooted crowns. They mature rapidly and produce runners that terminate in new crowns.

Beds are planted using either a matted row or hill method, though strawberries are also commonly grown in containers. The best way to fertilize strawberries depends on the method of planting.

Matted Row Method

Matted rows are fertilized to encourage runners and support root growth of new immature plants. Water the planting bed first, then use a watering can or hose with a fertilizer attachments to evenly distribute a water-based fertilizer. Apply the mixture as close to ground level as possible and feed plants early in the day to allow wet foliage to dry before nightfall. June-bearing plants are usually grown in matted rows.

Hill Method

The hill method treats strawberry plants as short-lived perennials by removing runners and concentrating growth in the initial plant which grows fairly large and produces larger berries. It is used more often with day-neutral and everbearing varieties.

Hilled strawberry plants are fertilized to support the continued health of the initial planting. Water-based, granular, or powdered fertilizers can be used since plants are spaced to allow side dressing worked in with a hoe or tiller. Water the bed well following application.

Container Method

Choose day-neutral strawberries to grow in containers. Berries grown in pots are treated as short-lived perennials and may produce for several seasons, but plants are often replaced every year. Strawberries grown in pots need to be fertilized every two weeks. Use a water-based product and water the pot first. Compost tea and foliar sprays are good choices. Water and fertilize at soil level early in the day to allow any wet foliage to dry before nightfall.