Nutrient supply for own-root roses – feeding

Nutrition: timing, dosage, results

For roses, a good feeding programme is mainly about timing: a starter feed in spring, top-ups between flushes of flowers, then a potassium‑focused feed at the end of summer and a nitrogen stop. Here you’ll find CRF and liquid protocols with indicative doses (worked in under the mulch), warning signs (over‑fertilising, deficiency symptoms), plus a separate section for pots and public plantings. Do you tend to give more feed, or are you worried it might not be enough?

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Quick principles Principles & materials Timing Dosage – CRF (slow‑release) Dosage – liquid Organic supplements Pots / patio Public & green spaces Signs & troubleshooting Tools you’ll need FAQ

Quick principles

Rule of thumb: always fertilise on moist soil, then water it in well.
Season starter: CRF in spring (3–4 months); top‑up after the first main flush of flowers.
End of summer: K‑focused feed; no N after mid‑August.
Ring application: scatter in a ring 30–40 cm out from the base, not directly at the stem.
Mulch: fertiliser should go under the mulch – for more even nutrient release.

Own‑root plants – good ability to regenerate; too much N gives lush but weak growth.

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Principles & materials

CRF (controlled‑release): 15-9-12 (+Mg+micro) or 16-8-12 for spring; 10-7-20 / 12-8-16 for summer.
Liquid feed: rose fertiliser during the season (every 2–4 weeks) – ideal for quick correction.
Organic: compost, worm castings, seaweed extract, biochar/zeolite – to improve soil structure and buffering capacity.

Because nutrient uptake depends on pH, measure regularly: Soil & pH.

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Timing

Spring: from bud‑swell, work a starter CRF into the soil.
After the first big flush: top‑up (CRF or liquid feed).
End of summer: K‑focused feed (helps wood to ripen).
Autumn: no nitrogen – it encourages soft growth that’s prone to frost damage.

The practical “last nitrogen” date is usually between 10–15 August, depending on your local climate.

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Dosage – CRF (slow‑release)

Type	Guide dose / plant	Notes
Mini / Patio	15–25 g	In pots, better mixed into the compost
Hybrid tea / Floribunda	30–50 g	Scatter in a ring and work in shallowly
Shrub / English	40–70 g	Bigger shrub = higher dose
Groundcover	25–40 g	Spread evenly over the surface
Climbing / Rambling	50–80 g	Apply near the supports, targeting the root zone

Method: fertiliser should go under the mulch; work in 5–8 cm deep, then water thoroughly.
Soil moisture: don’t apply to dry soil – water first.

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Dosage – liquid

Frequency: every 2–4 weeks during the season; reduce in extreme heat.
To the soil: always apply onto pre‑moistened soil (better uptake).
Rate: follow the manufacturer’s label; in containers, use a lower concentration.

Combined with mulch you get more even water and nutrient management: Mulching.

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Organic supplements

Compost: 2–3 cm layer under the mulch; improves structure and soil life.
Worm castings: rich micro‑life; good both at planting and worked into the surface.
Seaweed extract: boosts stress tolerance (after heat or drought).
Biochar / zeolite: improves buffering, holds water and nutrients (use in small amounts).

pH‑dependence and dosages: Soil & pH.

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Pots / patio

CRF in the mix: 2–5 g/L of compost (built up gradually), refresh the top 5–8 cm each year.
Liquid feed: lower concentration, but more often; don’t leave water standing in saucers.
Growing medium: open, airy mix (soil + compost + perlite/pumice); pH changes faster → test more often.

Positioning: Pots / patio • Watering: Watering.

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Public & green spaces

Protocol: incorporate CRF in spring, top up K in summer; liquid feeds only when needed.
Compost: 2–3 cm under the mulch each year; apply uniformly at bed/plot level.
Operations: before mechanical application, check soil moisture; water in via the irrigation system.

Positioning: Public & green spaces.

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Signs & troubleshooting

Chlorosis (yellow leaves, green veins): iron deficiency / high pH → acidify and add iron.
Thin, weak shoots, very dark green leaves: too much N → reduce it, shift to K‑focused feed.
Scorched leaf edges: over‑fertilising / dry medium → heavy watering and a temporary break from feeding.
Poor growth despite good watering: low organic matter → add compost.

Always fertilise on moist soil; avoid application during heatwaves and in full, scorching sun.

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Tools you’ll need

CRF rose fertiliser
Liquid rose fertiliser
Compost
Worm castings
Biochar / zeolite
Watering can / Hose

FAQ

Can I fertilise before rain?

Yes, ahead of moderate rain it’s actually useful; avoid feeding before heavy downpours as nutrients can be washed out.

Which is better: CRF or liquid feed?

They do different jobs: CRF covers the plants’ basic needs, liquid feed is for quick correction. Together they give the most even results.

When should I start again in spring?

Around bud‑swell (according to your local weather), then top up after the first main flush of flowers.

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Nutrient supply for own-root roses – feeding – PharmaRosa®