Fertilising guide
How to fertilise 'Black Krim' Tomato (Solanum lycopersicum 'Black Krim')— schedule & NPK
Also called Black Krim Crimean tomato.
More about 'black krim' tomato
About 'Black Krim' Tomato
Solanum lycopersicum 'Black Krim' · also called Black Krim Crimean tomato · edible
'Black Krim' is a Crimean heirloom beefsteak with dusky mahogany-purple shoulders and a deep, smoky, almost savoury flavour. This indeterminate vine colours best in heat and bright sun, producing large, soft-skinned fruit mid to late season. It needs steady moisture, staking, and good airflow; the thin skin makes it prone to cracking and bruising.
Growth habit: Indeterminate cordon producing large beefsteak fruit continuously until frost; train as a single stem on stout support and remove side-shoots.
Watch for — Green-shoulder / uneven ripening: Shoulders can stay hard and pale in heat; provide gentle afternoon shade in extreme sun and avoid heavy nitrogen feeding.
What fertiliser 'black krim' tomato actually wants — and why
'Black Krim' Tomato feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.
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.
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 'black krim' tomato: 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 'black krim' tomato, 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 'black krim' tomato:
Balanced feed at planting, then a high-potassium tomato feed every 7-14 days once fruit sets. The big trusses are hungry; steady feeding keeps fruit sizing without forcing soft, disease-prone growth. 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 'black krim' tomato 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 'black krim' tomato
Follow the crop-feed label rate for 'black krim' tomato — 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 'black krim' tomato first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the 'black krim' tomato watering schedule.
Signs you are over-feeding 'black krim' tomato
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for 'black krim' tomato:
- 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 'black krim' tomato
- 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 'black krim' tomato 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 'black krim' tomato 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 'black krim' tomato
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 'black krim' tomato — frequently asked questions
What fertiliser does 'black krim' tomato 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. 'Black Krim' Tomato 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 'black krim' tomato?
Balanced feed at planting, then a high-potassium tomato feed every 7-14 days once fruit sets. The big trusses are hungry; steady feeding keeps fruit sizing without forcing soft, disease-prone growth. Balanced feed at planting, then a high-potassium tomato feed every 7-14 days once fruit sets. The big trusses are hungry; steady feeding keeps fruit sizing without forcing soft, disease-prone growth. 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 'black krim' tomato?
Follow the crop-feed label rate for 'black krim' tomato — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.
What does over-feeding 'black krim' tomato 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 'black krim' tomato 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 'black krim' tomato?
In containers, fertiliser salts build up fast — water 'black krim' tomato 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.
Keep reading
- 'Black Krim' Tomato care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water 'black krim' tomato — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise tomato
- How to fertilise pepper
- How to fertilise cucumber
- All 1284 fertilising guides in the Growli library