Fertilising guide

How to fertilise Royal medlar (Mespilus germanica 'Royal')— schedule & NPK

Also called Royal medlar, medlar 'Royal'.

More about royal medlar

About Royal medlar

Mespilus germanica 'Royal' · also called Royal medlar, medlar 'Royal' · edible

A compact, spreading medlar cultivar particularly suited to smaller gardens. 'Royal' bears heavy crops of sweet-tart russet-brown fruits approximately 4 cm across, ripening in late October to early November. Self-fertile and generally pest-free, it thrives in full sun with moist, well-drained soil. Fruits must be bletted after harvest before eating.

Growth habit: Deciduous small tree; bushy and spreading; more compact and lower-growing than 'Nottingham' or 'Dutch', making it suitable for small to medium gardens

What fertiliser royal medlar actually wants — and why

Royal medlar 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 royal medlar: 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 royal medlar, 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 royal medlar:

Apply a balanced general fertiliser or well-rotted compost mulch in early spring. Avoid heavy nitrogen inputs. A potassium-rich feed in midsummer can encourage improved fruit flavour and colour. 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 royal medlar 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 royal medlar

Follow the crop-feed label rate for royal medlar — 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 royal medlar first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the royal medlar watering schedule.

Signs you are over-feeding royal medlar

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

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 royal medlar

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 royal medlar 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 royal medlar 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 royal medlar

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 royal medlar — frequently asked questions

What fertiliser does royal medlar 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. Royal medlar 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 royal medlar?

Apply a balanced general fertiliser or well-rotted compost mulch in early spring. Avoid heavy nitrogen inputs. A potassium-rich feed in midsummer can encourage improved fruit flavour and colour. Apply a balanced general fertiliser or well-rotted compost mulch in early spring. Avoid heavy nitrogen inputs. A potassium-rich feed in midsummer can encourage improved fruit flavour and colour. 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 royal medlar?

What does over-feeding royal medlar 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 royal medlar 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 royal medlar?