Fertilising guide

How to fertilise Strawberries (Fragaria × ananassa)— schedule & NPK

Also called garden strawberry, pineapple strawberry.

About Strawberries

Fragaria × ananassa · also called garden strawberry, pineapple strawberry · edible

Strawberries are low-growing perennial fruit plants ideal for beds, containers, and hanging baskets. June-bearing types produce one heavy summer crop, everbearers and day-neutrals crop in flushes from early summer to autumn. Pet-safe; fruit and foliage are non-toxic.

The garden strawberry, Fragaria x ananassa, is not a wild species but an 18th-century hybrid of the South American Fragaria chiloensis (large fruit, from Chile) and the North American Fragaria virginiana (small, intensely aromatic fruit), combining size and flavour.

Avoid heavy nitrogen at fruiting, which produces lush leaves and soft, fungal-prone fruit; renovate June-bearers after harvest and feed then so plants build crowns for the next year's crop.

Growth habit: Low rosette perennial spreading by runners

Watch for — Yellow leaves: Nitrogen or iron deficiency, or compacted soggy soil.

Sources: en.wikipedia.org, botanicgardens.uw.edu, missouribotanicalgarden.org

What fertiliser strawberries actually wants — and why

Strawberries feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for strawberries: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed strawberries, and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For strawberries:

A balanced feed in early spring and a high-potash tomato feed every 2 weeks once flowers appear. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

The dormant-season rule matters more than the exact interval: skip feeding entirely when strawberries is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for strawberries

Follow the crop-feed label rate for strawberries — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.

Feeding always goes onto already-damp soil, never dry roots — water strawberries first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the strawberries watering schedule.

Signs you are over-feeding strawberries

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for strawberries:

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen).
Lush foliage hiding the crop; soft growth prone to pests and disease.
Salt crust on the soil and scorched leaf edges in containers.

Signs you are under-feeding strawberries

Pale, yellowing lower leaves and stunted growth.
Small fruit, poor set, and a quickly exhausted plant.
Blossom-end rot and weak cropping from erratic or insufficient feeding.

If the symptoms point at watering, light or roots rather than nutrition, the full strawberries care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

In containers, fertiliser salts build up fast — water strawberries thoroughly so excess drains from the base each time, and flush pots with plain water every few weeks to prevent a damaging salt build-up.

Organic vs synthetic feeds for strawberries

Organic options

Garden compost or well-rotted manure dug in before planting, plus a liquid comfrey or seaweed feed once fruiting starts. UK: comfrey feed or organic Tomorite; US: Espoma Tomato-tone or Neptune's Harvest. Builds soil and feeds in one.

Synthetic / liquid feeds

A balanced feed at planting then a high-potash tomato feed in fruiting — UK: Growmore at planting then Tomorite (Levington) or Phostrogen; US: a balanced 10-10-10 then Miracle-Gro Tomato or a bloom booster.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising strawberries — frequently asked questions

What fertiliser does strawberries need?

Balanced (even N-P-K) at planting for roots and frame, then switch to a high-potassium ("high-potash") tomato-style feed once the first flowers open — potassium is what sizes and ripens fruit, not nitrogen. Strawberries feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

How often should I feed strawberries?

A balanced feed in early spring and a high-potash tomato feed every 2 weeks once flowers appear. A balanced feed in early spring and a high-potash tomato feed every 2 weeks once flowers appear. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

What strength of feed for strawberries?

What does over-feeding strawberries look like?

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen). Lush foliage hiding the crop; soft growth prone to pests and disease. Salt crust on the soil and scorched leaf edges in containers. Staying on a high-nitrogen feed once strawberries starts flowering is the classic error — you get a huge leafy plant and a disappointing crop. Switch to high-potash the moment flowers appear.

Should I flush the soil of strawberries?